HEAT PUMP or BATTERY STORAGE only one saves money (UK 2022) 

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Great Video! as a Givenergy installer in the UK I always get asked this question about heat pumps so thanks for making it so clear.

Nice straightforward presentation of the facts. There is one limitation I have recently become aware of the maximum supply rate to a house has a limit unless you have the main supply upgraded. This places a limit on how much most people can download during the off peak rate period. Worth including in your calculations. 👌👍

Hi, very interesting analysis however you calculations seem a little bit off. You refer to the running cost of you EV as a saving, however that night time saving to charge your car would be there even if you choose to do nothing other than set the car to charge overnight, so really shouldn’t form part of the overall calculation when talking about battery installation. How on earth can you say that the night time tariff isn’t worth using unless you install a battery that’s totally wrong as your main saving is in charging the car and not the battery. Your costings have to be base only on Charging the battery with cheap rate electricity and under those circumstances the payback period would be much longer. Just one other point people always talk about payback, I believe there’s more to it than that, it’s also about burning less dinosaur juice and the fact that having fitted a battery, solar system, and heat pump one’s house goes up in value. The investment isn’t lost just parked until sale time.

Nice and succinct video. I have very similar scenario. One other consideration: If you expand storage, then you can power the Air/Ground Source Heat Pump at the much cheaper Tarrif also. However, one omission: you need to 'set aside' a proportion of the savings, as storage solution(s) won't last for ever. Totally agree the storage is the logical step, especially after going E.V. Hopefully the 'Heat pumps' will get better efficiency with new Motor tech etc. and Storage will get more economic too.

Superb techno-economics Neil, always straight to the point - many thanks

Neil: Your analysis illustrates the 'problem' with heat pumps that not everyone understands: the difference in gas and electricity prices (while it remains) does not make heat pumps significantly cheaper to run than gas boilers - never mind the considerable up-front cost, which is why I think gov't grants for heat pumps are crazy when that money should be use to improve insulation. Furthermore, the reported dearth in heat pump engineers may (?) mean that the annual service to keep them running efficiently is rather more expensive than for gas boilers - something that no-one ever mentions when I read articles about HP use. For a start, if affixed up a wall, requiring a ladder to access, that, apparently, immediately adds to servicing cost of some £30-£50! Would you know what an average annual service costs? I bet it's more than for gas... I take your helpful point about battery storage. Perhaps there's one caveat: that as more people charge EVs using night-time rates, as well as for battery storage, will that cost difference reduce over time? Much like gov't incentives to buy EVs have all but disappeared now that more have them, will 'night-rate' elecy go the same way? I guess we can only speculate... Thanks for your useful analysis. I have solar but no EV. As a lower elecy user storage makes no sense for me given the payback time. An EV would likely change that. Perhaps one should add (the obvious?) that so far as I read, while solar/battery is not now thought to damage property sale price, the investment is not thought to enhance it much either (as an architect you may know more, but estate agents venture this opinion), such that if there's a reasonable prospect of a move in the next several years or more, that should cause pause, albeit that as elecy prices increase the advantage of money-saving tech will be more attractive to potential buyers.

What a crisp, to the point, full of facts, video with numbers based on real life products. Thank you Neal, just what I was looking for. I have solar panels but wasn’t sure if to get ASHP or battery back up. I see you have a Tesla, if not already done, I would like to see your review on its + & -. Personally o think Tesla needs a few years to iron out it’s done very basic issues plus I really despise and tablet stuck in the middle of the front dash. Thanks again for a fab video.

Pretty bang-on with the calculations. I'll add a few points I think might be useful to know for people (I'm ASHP+Solar+battery owner): - When replacing an older boiler like oil-fired, biomass or gas backboiler, your ROI might be sooner. We replaced a backboiler which was on it's last legs anyway & 20% less efficient than todays condensers, so overall our running cost is about the same or slightly cheaper now. A condender system boiled would have been 3k+ anyway. - On an EV tariff which doesn't strictly require an EV, you can auto-program your ASHP thermostat to pump as much heat into your building as possible in the cheap hours, whereas you don't have a cheap gas window. If you want to do this, look into adding a buffer tank to your ASHP install too for a bit of extra thermal storage. - EV tariffs are a double-edged sword, and only really become cheaper if you have Solar to supplement the expensive day-electricity. Otherwise your day cost will most likely outweigh your night cost, unless you have an EV to charge. - If you do have an EV AND and heat pump AND a battery and you want all those things to charge in the cheap tarriff window, and you might have a tumble drier & pool heater if you're posh, you might need 3-phase depending on what your EV charging rate is. - ASHP install will need to be part of an unvented, mains pressure system. If your house is currently gravity-tanked, you need to add the system upgrade into the cost. Mains pressure showers are so worth it, and the hot/cold pressure being balanced is amazing. - ASHP will drain the battery very quickly, depending on what it's doing. For easy maths, a 10kwh battery will be drained in about 4 hours when maintaining heat in a 4-bed average UK house with other things on. When it comes to battery, my belief is go big or dont bother. 16kwh+, you really want to to last 24 hours if possible. And have more than 16a charging capability so it can be charged full in under 4 hours in the cheap EV tariff window. - I think ASHP + battery + solar is the full package where it all starts to make sense and be greater than the sum of the parts. Otherwise, your returns might be slower/never happen.

Really good vid thanks, clacs were really spot on, if you added solar to charge the battery during the day this would reduce your electric bill a better way although the initial cost is roughly 6k for 4KW decent system with microinverters

This is just the explanation I was looking for as I've been considering these as well. It would be useful to know what difference solar panels would make, as I have them fitted already, and considering adding more.

Thank you for such a concise professionally detailed and edited video with visual price explanation (Genius). On Top of your 8.2kWh system saving ‘your’ systems £1,428 a year (with a break even of 3.47 yrs, you would also save a further £9,390 for the first 10 years or £23,770 for the first 20 years, after payback/breakeven or factoring in any future price increases. If you have solar and end up generating excess energy, saving this to your battery far out-ways any pay-in tariff and makes this figures even greater. PS There would potentially be some battery degregation over time. WELL DONE

Really helpful and looks like my decision to install battery and solar was the right one. You might also look at Tepeo an electric system which replaces a gas boiler without having to upgrade radiators etc but works on the same principle. I don't kniow the price. the everything electric show youtube channel had a video.

Thank you for posting this Neil. Compelling facts.

Thank you for this analysis. I have storage batteries and am very close to off grid full time. You touched on a very important point. Let me explain. I do everything I can to control when I purchase energy from my utility. For example, most of my power tools are battery operated, this allows me to charge batteries when the sun is out or off peak times when energy is cheaper or my house batteries are full, just like you do with your EV. My EV charges during the day, again when the sun is out or in your case at night off peak. My vacuum cleaner is a battery operated robotic vacuum that runs when we need to clean but what's important is that I CONTROL when to charge it. What you want to do ideally is be able to control when you use energy. Our water heater is tankless, this might raise some eyebrows but, again, I control when to use hot water. All our small usage like hand a dish washing doesn't tax the PV even though the tankless is wired for 20kW. You only use that amount of energy when it's at full house flow rate, several people showering, washing machines going etc. At our shower rate of 1.5 gpm it only uses ~5kWh which the batteries can cover. If we shower when the sun is out the PV covers the requirements of the tankless, off hours , no sun the batteries do. You would think that 5kWh is a lot for the batteries but it's not. Here's why: I take 4 or 5 minute showers which is about average for people but let's say I took an 8 minute shower. 8/60 x 5kWh = 666 watts to take a shower. That's easy for the batteries and inverters to cover. If we had a HPWH then we couldn't control when it heated water so it would cost more in the end, worse there are standby and line losses that don't occur with tankless. I heat the house water to ~40C a HPWH heats water to 49C or more, that's wasted energy. You get the idea, that's what you're basically doing with your EV, you are controlling when you use energy - this is the key to savings.

Solar PV can be added to a battery system. It's also been interesting to see a few people experimenting with solar air heaters and heat pumps.

Really interesting comparison. I've got battery storage, 2x Givenergy 8.2KwH = 16.4, with 5.6Kw of PV panels on the roof. Total installation cost 2 years ago was £12k. Also have an electric car that either gets charged from the solar generation or overnight on Economy 7. Only drawback with the system so far is that the inverter has a max input/output of 2.5Kw. However, I believe the latest inverter from Givenergy can do 3.5Kw. Perhaps you should add PV panels to your comparison? Did you consider a ground source heat pump?

As someone that fits both various types of heating systems and battery storage, Battery Storage before Heat Pumps every time. There are the factors you've stated but beyond that which people often aren't informed of or don't think about is decorating after an ASHP installation, the hidden costs so to speak. With Battery Storage and solar it's generally minimal distruption and doesn't effect decor to the same degree as fitting larger radiators (if possible), having the floors up to run correctly sized pipes (if within budget) and although we will make good on our company we can't match in the decor or guarantee the floors especially if they're laminate coverings etc will come up without damage. Also Air-to-Air heat pump systems are far more efficient than the water based ones due to the temperature delta being 15 instead of 45. Generally though if a Gas appliance is pre 2001 (non-condensing) Solar + Battery or even just battery on its own and swapping tariff will often save more money than a heat pump. The easiest thing you can try is running the current system flow temp at 55c or below to see if the property maintains temperature. If it doesn't don't swap, get more insulation and consider the battery storage, they'll make a bigger impact in the majority of cases.

That was very interesting and potentially useful. As you mentioned in your pinned comment #4, the off-peak tariff is no longer offered by my supplier, which might have helped us as our son has an EV and we also have a garden spa (sounds posher than hot tub!) which could use night time electricity for heating. We are having a stand alone wall mounted air conditioner/heat pump fitted for summer comfort and winter heating supplement- our normal heating is by gas boiler & radiators with a gas fire that can also be used in the event of power cuts. Have you had any advice on the maintenance costs and battery life? I also have great concerns about the robustness and spare part availability of control systems- I have noticed a worrying trend of recent electronic failures. In the last few years since we had smart meters installed, 3 have failed with another that failed during its installation. We also had to replace an oven due to a burned PC board- never had these problems with British made ovens-our Creda with eye level grill lasted fault free for 27 years.

Thank you for a well laid out video... spoken in lay mans terms.. I have Solar panels with FIT...and was concerned which way to go in an older property... (1970's bungalow ).... the thought of going thro new radiators, replacing a gas boiler not even 5 years old etc etc.. and all the upheaval involved....... I spoke to several friends with batteries .and they all said it was batteries all the way...they had turned heating water / rad temp down to 55 degrees ,,, and were not impressed with the heating of the house...........No one I know has ASHP fitted ..These all seem to be fitted in NEW BUILDS with Under floor heating .with modern insulation etc............. . .SO...... I chose Batteries a few months ago and watching this video has made me feel " I've made the correct choice "..

Also a self employed ARB architect (I resigned from RIBA after 30 year membership in disgust at what has happened to the Institution). The coefficient of performance you quote at 3.5 for the ASHP is EXTREMELY optimistic, even as a maximum value, and would only ever apply when it is warmer outside than the latent temperature inside. When it is colder outside, there is literally no heat to be gained from the environment and you are working 'compressor only' and therefore have very expensive electric heating. ASHP in the UK are 'economic' for very short periods in spring and autumn. Also, just like the former 'green new deal', government funding is only available by using 'approved installers' who's costs are higher than non-approved installers, so once again the apparent subsidy is enjoyed more by the installer than the consumer. 'Payback' for ASHP installation is likely to be beyond the useful life of the equipment. The significantly larger radiators required lose wall space. I have recently reluctantly facilitated a whole house refurbishment with ASHP, but only on the basis of UFH at both levels (and my thoughts on UFH on a timber suspended first floor are from bitter experience still cautious despite using what at first reports seems to be a good product from Celecta) and solar electricity generation and battery storage to feed the compressor. All in, the changes to the floors, the ASHP and the solar with battery have added some £45k to the project which I fear will never be offset in use. Edit: I nearly forgot; with two rapid EV charging points along with the ASHP, Western Power determined the property needed to be upgraded to 3 phase which meant pulling in a new cable up the drive!

Great vids. I think if you could factor in the cost of adding solar cells to charge the battery during the day and adding a grid tie system to sell on extra generated solar power to your electricity supplier, it would be interesting to see the cost and savings.

Certainly one of the best videos I have watched on the subject. 🙂There is a lot of greenwash and grossly unscientific discussion on you tube but this is not. (and I am well qualified to know the difference!)

You also have to factor in the costs of insulation and improvements to existing pipework to make an Air Source Heat Pump a viable alternative source to a Gas Boiler - in many older properties you'd have to rip out all of the existing pipework because it's bore is too narrow - I am on a journey (it will take us about five years I reckon) to wean ourselves off Gas and move to an ALL electric based energy source, which will involve - at various stages of the process: Ripping out many of the existing radiators - particularly those on the upper floor Installing Battery Storage Moving to the dual period electricity tariff referenced in this RU-vid video Changing our ICE vehicle to an EV Installing electric underfloor heating - particularly in rooms on the upper floor Installing Solar Panels and linking them into the battery storage Significantly improving the level of insulation in the house generally - cavity wall and loft insulation? Replacing the smaller number of radiators we retain with more efficient modern alternatives Replacing our gas boiler with an electric alternative Our house was built in 1952 - I've looked at an Air Source Heat Pump and ruled it out as NOT feasible, due to the huge cost and disruption involved in making it work as a potential alternative to a Gas Boiler

Thanks for the insight

I love the fact people worry about the payback period. When we renewed our kitchen in our last house the question of a payback period never came up because we did it to suit us. If you can afford to stop burning gas, coal, oil or whatever then do it. If you use a lot of electricity then a battery makes perfect sense especially as an EV owner plus you can now get EV tariffs and charge the car and battery at 7.5p per Kwh. .

Thought I’d add my situation, I’ve and east west solar setup with a Powerwall a Zappi car charger and an Eddi that diverts solar to heat water. I’m also fortunate that I got in when FIT payments were about to be fazed out so I also get about 8 p per kWh generated with amounts to around £400 a year. The Powerwall holds 13.5 kwh of energy that’s charged up during the winter when there’s little solar, on night rate electricity currently, 7.5p per kWh. That is usually enough to see us through the following day. Before the current crisis our total gas and electric bills, when all was taken into account was near to zero. That’s allowing for the FIT payment and the estimated amount I spent each month on diesel that I no longer have with our Kia Nero EV. During the summer months our car is charge up on excess solar energy.

We've had 10kwh of batteries since April, based on their discharge readings they've saved us about £600 so about £100 per month. That does include some charging from solar but it's mostly overnight. Total cost of the system was about 11k so it's returning about 10% per year but I think if we'd just got the batteries we'd still get most of the saving

Love the fact that you provided very detailed numbers, in terms of kWh instead of just costs (which are too variable these days). I have a few questions regarding your battery savings: 1. Did you factor in the round trip efficiency of lithium batteries? - My understanding is that it is about 95% for DC to DC, i dont know if there is more losses converting between AC 2. Did you factor in depth of discharge? Typically doing a 100% discharge each day is pretty stressful on a battery, even lithium. And will typically drastically shorten lifespan (based on mobile phone wear atleast)

that has blown my mind definitely interesting food for thought

Really interesting video - thanks for sharing your thoughts on this. I'm an EV owner too (BMW i3 33kWh) and consume around 2800 kWh of electricity per year to drive 12k miles. In addition we consume another 6800 kWh for other household loads. Our heating is an externally mounted oil fired boiler which is around 14 years old now and is starting to need regular repairs so we were considering a heat pump, potentially ground sourced since we have a 3 acre paddock next to our house. The house is partly a 150+ year old cottage with solid stone walls, and partly an 2 story extension which was added in 2008 so we have a mixture of insulation standards which was a big concern for me if we were to install an ASHP or GSHP. I'm currently refurbishing a 10m x 10m outbuilding next to the house and intend to fit solar panels on the roof but the lead times on installations are pretty long just now for obvious reasons. I did wonder if I should try to get a battery installation in the shorter term to allow me to switch to a tariff such as Octopus Go. We were with Octopus Go at 14.5p and 5p (00:30-04:30) per unit before the energy crisis but the rates are now 35p and 7.5p so the penalty for using power outside the "Go" window is much more severe. The result is that we are better off staying on the standard variable tariff which is 29.84p peak and 21.34p from 01:30 to 08:30hrs. If we did employ battery storage then we'd probably need 2 of the GivEnergy 9.5kWh batteries to deliver the 18kWh or so that we consume daily excluding the EV. So I guess I need to do a few calculations to work out the return on investment of a battery system for my situation but it sounds like it might be feasible. Advice welcome. :)

Great video. My real world consists of solar panels and a Give Energy battery. At the end of the day this gives me free electricity, which runs my house and my car too. Combined with FIT (Feed in Tariff) I also receive payments, which I use to reduce my gas bill resulting in great savings. An air source heat pump would mean purchase cost of far more than I paid for a battery, replacing my rads, my combi boiler, my micro bore pipes, installing a water tank, plus cost electricity. This would mean an ROI for me which I would never see.

Interesting Topic and your correct that a battery set up will be more beneficial than Ashp . Your Ashp will almost certainly not provide the cop you quoted. Add solar Pv to your battery set up and your savings will be even more . The government hasn’t thought this push for Ashp through properly and despite what’s being said I believe the gas boiler will remain. Tests are already underway in the Uk where they have added a small percentage of hydrogen into the gas and this has had the effect of bringing down emissions to almost zero which is the main goal. Worcester and Baxi have already began manufacturing hydrogen ready boilers. Instead of rushing in buying electric cars , Ashp etc … I would suggest waiting 2 or 3 years and see what develops plus I wouldn’t base buying batteries on the premise that cheaper nighttime rates will always be available.

Air to air heatpumps, AKA Aircon, are much cheaper to buy and fit than air to water HPs. There is minimal disturbance because no new rads have to be fitted and you get cooling on hot days. Air to air is more efficient too, because there is one fewer heat transfer process. No regular maintenance is needed either. Downsides, which no-one talks about, are low level noise, no hot water, and the de-frost cycle which periodically sucks heat from the house to clear ice from the outdoor unit on cold humid days. Aircon works well with solar pv, providing cooling at zero cost during the day. Battery storage can return the free solar electricity at night to give cool bedrooms. Aircon already benefits from the economies of large scale manufacturing. It is only the Brits who seem to be stuck in the past with water based systems.

This is a really good video. It clearly makes the point that ASHP only reduces the heating/hot water costs. So many ASHP evangelists never mention the sky high electric costs. I deal with all forms of boilers/ASHP/Solar etc and the bottom line is there is no silver bullet that solves all problems. Ideally we could have solar feeding battery storage and then the heat pump but you just need several days of poor sunshine and you are in trouble again. In the current economic climate, the main reason I'd have for installing a heat pump is for cooling during the summer months. This is becoming a big concern in the UK, especially for homes that are well insulated for the winter but have poor ventilation during the summer.

one thing to consider is future expectation of prices. Gas is supposed to significantly increase this year and medium term may tilt things towards ASHP. Also if you had a battery too - your ASHP can benefit from the cheap rate (although you’d need a big battery..)

I have just installed a heat pump via Octopus Energy. I agree this isn't going to save much on running costs but initially I am doing this for carbon reduction . It has cost me £6k and includes replacing 11 of my 14 radiators. My boiler was due to be replaced so I would of spent maybe £2.5k ish anyway and our old radiators were a bit rusty and dilapidated. I have an Electric car and solar panels which is already saving about £900/annum overall so the next step will be a battery which will also help to reduce cost of running the heat pump a bit using cheap night rate electricity and maybe some solar that we currently export in the autumn and spring months.

You also have to consider the fire hazard a battery holds. If it malfunctions and starts a thermal runaway youll have a hard time stopping it and depending on the position its been installed a 30/60min firewall wont hold it back

Thanks for sharing, the numbers stack up for your circumstances, have you considered PV and battery at the same time? You would save the VAT doing them both together? I would add that your electricity consumption even without the EV seems rather high - have you looked at reducing this first?!

I think you ought to have included a 3rd scenario here which is installing the heat pump but switching to the dual rate electricty. You still get that 1000 saving on the car, even without the a battery. If you install a water cylinder large enough for a day's usage then it can be heated on cheap rate overnight. Your home is well insulated so you could at heat it up overnight on cheap rate (using the last few hours probably best) and lower the temp during the day when it's less cold outside anyway. You'll probably have to use some heating between sunset and cheap rate starting up but this could be kept to a minimum. Most of the year you probably won't need much peak rate heating except when it's very cold. Your water heating could be on cheap rate all year. Depending on how much other electricity you use during the day and what time your cheap rate starts etc I would expect that you would save money overall by switching to dual rate, especially given the huge savings charging your 2 cars.

Very useful information and done fairly this is my out come too looked at air source heat pumps for 3 years now and had about 6 quotes now and still can’t make the figures work until the gas boiler dies then might look at it again or air to air system. Had solar before in last home and loved it so when Ashp didn’t work out cheaper we went solar and battery storage at our next home and last year saved over £2500 by not buying fossil fuels and running our 3 bed home from solar in the sunny months and from off peak electric in the not sunny weather and even in less than idea array position of near west with winter shading issue solar has worked super ! Near 6000 kWh of solar in the first year on our 6.2 kWh solar 13 kWh battery storage and solar ev chargers to charge our model 3 . Would love to go home fossil fuel free but with limited budget ashp is not right prices for us yet . Thanks for your video and take care and safe travels everyone. Solar and evs are a win win for those that can afford them but if you can invest in your tomorrow I my opinion go solar battery storage first then if you do enough miles or have spare money then go ev then asap or air to air or ground source heat pump depending on your home size and requirements

Hi Neil, Did you check out air to air heat pumps. You can get a 2.5 kW one for about £600. They are simple to install.I guess installation would be about £600. You could then run it at night To provide a Minimum temperature says 16°. I know this would be forced air so unless the building was moderately air tight , you might lose quite a lot. The added benefit would obviously be air-conditioning in the summer. I have installed these myself to anyway you Cant put a gas boiler.

3.5 gain on your heat pump is very optimistic. When temperatures are below zero expect no better than 2 times. This is why they should only be used in very well insulated houses that already use little energy because direct electrical heating will be used if the heat pump output drops too low.

We have a converted/extended 1950's bungalow of about 200sqm that currently is heated by an all (solid) fuel central heating cooker. Our annual solid fuel cost is around £750.00. Our electricity consumption is via E7 dual rate with about 43% consumed at night on the low tariff. Our electricity costs from Oct 2020 to July 2022 was ~£950, the annual rate is not consistent for this overall period. I can reasonably convert to heat pump but I will require a 21kW unit that is probably best on 3 phase, which fortunately is immediately available. The house plumbing and rads is already sized for lower flow temperatures as required with the CH cooker although I might simply fit split units off individual units around the house. I will keep and maybe upgrade the CH cooker as it has valuable advantages over simple heating/HW

Would you consider the savings made by swopping the gas with heat pump and supply with battery it seems a viable option. Storage tank as buffer which heat up with night tariff with heat pump also would work.

Good video, promotes thought! A few things missed. Depth of discharge is usually 80%, so really only 80% of the battery available or the batteries will degrade too fast. Losses in converting AC to DC for battery and the back again. Also 15kWh is a lot for two people you should be able reduce that quite easily, requiring a smaller battery. Time shift energy to cheap rate for high demand appliances, washer, dryer, dishwasher ,bread maker etc. Octopus Go are still offering 7.5p kWh cheap rate in Aug 22. That all being said, I have a 20kWh battery array going in next week to move 100% of my electricity to off peak 7.5p kWh. With peak rates moving to 50p kWh this winter that gives me a less than 5 yr ROI on a system that should run for 20 yrs. Using the monthly savings created back into an interest free loan paid for a new system gas boiler and immersion heater and moved them so in 15 years all ready to put in a new heating system. This allows me to move hot water generation to cheap rate high efficiency and off the 58% gas efficiency for hot water supply and using batteries to ‘top up’ hot water during the day. Finally adding 2.8kWh solar array to roof of our shed, cheap to install and reuses battery inverter during the day to top up battery. Allowing me to go longer without gas boiler central heating. At some point in the future when cheap rate is not as cheap will add another 8kWh to the main roofs.

Put your washing machine on timer mode and timeshift it to the cheap period: that's about 2kw a day you don't want your battery to have to supply. Also get solar if you have a South or east facing: it just takes a sunny morning and that 9kwh battery will charge to full from around 20% by lunchtime if you can fit even a 3kw system (like mine), meaning if you keep an eye on a solar forecast you can get away with only charging to 50% overnight way more often than you'd think. Without solar yeah - just charge to full every night, but consider keeping an eye on your usage patterns and setting it to discharge only at certain times or avoid others: the oven will suck huge chunks out of it, for instance, and you don't want it therefore going flat right before you start cooking, because thats likely 3kw or so which is a significant percentage of your daily usage, like the washing machine, but it's something you simply cannot timeshift to the early hours. Slow cookers and air fryers are also your friend with a battery, especially slow cookers. Laptops + external monitor and keyboard/mouse are better than desktops. And so on: you want low constant draw more than you want big hits. A dehumidifier rather than a tumble dryer (unless you have a suuuuper efficient tumble dryer but then you're an architect you can probably afford one of those and a house big enough to fit one lol! I... Do not). The exception being your kettle, unless you want to get a caravan kettle and wait five minutes for boiling water, that's an inconvenience too far for us :) I've no idea about the heating options I'm still thinking about them, but I figured before I electrify, I should look at generation and storage, so as to be able to have money to save for the heating and water. So far... Yeah it was definitely the right decision. I don't really know why the govt aren't providing grants for my kind of set up, if not just doing it at scale - I did some quick maths last night and assuming there were no savings from economies of scale it would cost 16billion to install 32gw of solar and battery storage - only 1 billion of that is panels - and take up only 1m square metres which is about 8 X 100m X 100m space per county in England, far less if we include all of UK, which of course we should. There must *easily* be that kind of suitable roof space in the UK. Provide the 5k grant for up to ~10kwh battery storage per household, space permitting OR towards a heat pump. Or other generation/insulation/storage systems. Now is not the time to limit options not with our housing stock! Anyway, the money is 5k up to 30k houses per year for 3 years: a mere 90k homes and a mere 450million over 3 years. So spend 1bn more and give over 8 x100m square space per county to solar farms, and pump as much money as possible into whatever grid storage systems are cheapest per watt at scale, and let householders pick up the best energy saving/generation/heating/storage options work best for them. Aaaaaaaaa frustrating! ANYway: Please start designing space and physical support for all this kind of stuff, if not designing it in in the first place. If govt won't legislate it's up to firms to just... Do it. ...er.... Bit of an epic comment. Enjoy the rest of your bank holiday Monday :D

Good video, I'm am electrician and engineer who lives in Finland and has a ground source heat pump with underfloor heating. As you might imagine we have very cold and long winters. My house is 205m2 and we only use about 12000kwh per year. That's everything, heating, cooking, cleaning and lighting. The main thing what has to change in the UK is the insulation levels of houses. Given your average temperatures there is no way it is necessary that you should be using that much energy to heat that size of a home.. my home is also 20 years old. Also one thing to consider with batteries is their life span. They will most likely need replacing after 10 years. This of course depends on the battery type and conditions, charging controller etc

This is a well thought out video however there are some further understanding and calculations regarding peak power and use curve you need to consider. I know this as I followed a very similar process before installing a ASHP, solar and batteries. Your battery output is limited to your inverter output and battery discharge rate. If you exceed either of these figures you’ll draw from the grid even if your battery has change. For example. Taking the givenergy system you mentioned, the inverter has a max discharge capacity of 3.6kwh and battery 2.5kwh the most you’ll ever be able to draw is 2.5kWH at any specific time (according to Givenergy). So, you come in after work, you turn on a few of your appliances, kids doing the same and whilst you’ve got the cooker and Kettle on you’re drawing 4kwh. 2.5kwh from your batteries and 1.5kwh from the grid. At the end of the day you’ve used 10kw but only 6kw from the battery. The second issue already alluded to is battery utilisation. Your calculation assume full utilisation of the battery. Whilst you may be using more than 8.2kw a day, if your peak energy exceeds your battery delivery ability you may not exhaust your battery thus making it less efficient. So, you need to understand not just your energy use over time but also your peak energy curve and ensure your system matches it. For example, if you find your do exceed 2.5kwh at any time you could fit 2x 5kw batteries and a 5kwh inverter allowing you a max discharge rate of 5kwh. This however costs more. The only way I could get the numbers to work was to install an ASHP, solar and batteries. The heat pump was a 12kw, 20kw of batteries with 8.6kw of inverters and 6kw of solar. I had to pull in a few favours and accounting for government insensitive my projected energy costs including investment should be between £1500 and £2000 for a large 5 bed house. Investment cost written off over 10 years. HTH

Off-peak electricity will become more popular with more battery installations, so given the law of supply and demand, there will be no savings (soon) by using a battery to cleverly "buy low and sell high". As you mention, the availability of the night rate (off-peak) has already been discontinued in some places.

It's sad but true that the consumer comparison is so often "how much money will I save" and not "how much carbon emission will I save", whereas the government funding is looking at the wider social cost of the carbon emissions. That said, I would definitely do the solar + battery as the first stage - possibly over-speccing the battery to help keep the cost down when you do the second stage and install the heat pump.

Great video, thanks. I'm in a situation where I'm trying to move away from oil heating and stinky oil tank that comes with it (no gas where I live), so the main purpose would be for heating water and the house. I think this means air source would be the better option for me, as much as I would prefer solar + battery combo. I see you're a Bulb customer too - do you know if they will honour the reduced night tariff once we're moved to Octopus?

I'm looking at both of these options, looks like for me battery and solar first. My only comment is that obvs you shouldn't subtract the EV overnight saving as this is possible without the battery. But even saying that, i would say with the current electricity costs you are looking at less than a 10 year payback for a battery.

Thanks, I have an old house, very old (1686), so ASHP would be almost impossible, 24 inch walls etc. So I have gone for the usual insulation and now have Solar, home battery, and EV with V2L. I am reluctant to go above my 7.5KWh home battery as the pay back is long, and totally reliant on cheap night rate, if we all get a home battery then the suppliers may no longer offer cheap night rates. Even so I am now updating white goods to high efficiency and load shifting.

I am currently planning a new build 4 bedroom bungalow and I am researching both Air and Ground source heat pumps, both have their advantages. I was quoted £13.2k for air source which included a 100L and 250L water tanks. The calculations say a saving of £878 per year. I am also looking at solar, the property will have 3 phase power so the Giv energy is no good, there are some 3 phase systems which will cost about £11k with batteries and PVs.

Thank you very much for your work. I live in Eastern Canada (Quebec). Hydro Quebec is promoting a package which consits of a heat pump combined with heat storage unit within a forced air furnace. Am I wrong in assuming this is a very appealing combination? The utility 's goal is to eliminate the burning of fossil fuels. Thanks again.

Have you done this comparison with one of the phase change material heat batteries such as those made by Sunamp instead of a boiler. Would be very interested to see how that would compare to these two options

Air source and ground source are only viable in new builds with room for the storage tank etc, end of. With regards to battery storage, make sure you note maximum loads as the givenergy can only discharge 3.6kw meaning you will kick in mains for a top up if you put the kettle on and have a standing 400w running house (tv, wifi, fridge freezer etc). Powerwall and some others discharge at 5kw continuous and if used with solar are ac coupled meaning the solar can add to this (we personally can sometimes be feeding 9kw from our battery and solar continuously).

In NZ with ASHPump air to water doing hydronic underfloor heating in a well insulated but cold climate .Night 10hr/day14hr tariff of 6p/20p daily charge 17p .It costs 11 times 6 = 66p/night to heat house .Wood burner needs to supplement space heating for about 4 hrs once a week over coldest 3 months. Well designed house (thermal mass and eaves) mean no summer cooling needed. I have EV also so 6p/kwh drives 3miles ie 2p/mile. Soon we will be able to use the EV car battery as a storage for house use saving the wall battery cost. Yearly usage is 8500kwh at 2.6 pounds a day.

You should mention that heat pumps act as a grid stabiliser. The more heat pumps there are, grid base load would be relatively higher and peak load lower - this would allow us to have cheaper electricity generation. Alot of people forget that heat pumps are the often most efficient way to use ANY source of energy to heat a building. It makes more sense to burn gas in a power station to make electricity for heat pumps than to pipe it to homes to burn for heat. (A modern power plant is about 40% efficient after transmission losses), 10megawatts of gas procures at the power plant 4 megawatts of electricity Electric resistive heaters would give you about 4 megawatts of heat Burning the gas in the houses would give you about 9 megawatts of heat (we are very good at getting energy out of fuel on site) - so seems rational to do this... BUT. If you use that 4 megawatts of electricity in heat pumps COP 5 you end up operation at 200% efficiency of the gas, a 100% bonus. Literally more energy than the gas itself contains ends up being put into buildings. You only need COP 2.5 to break even with on-site fuel burning, and COP 6 units work in most environments.

Good, interesting video. I assume it's been mentioned elsewhere, but it's not exactly an apples to apples comparison. You already have a working boiler, but you don't have any energy storage. So you've already paid a fairly hefty sunk cost when you had the gas boiler installed or when you bought the house. You might not think about it in those terms, but you of course factor the fact that a house has a functioning boiler when you buy it and would lower the price you are willing to pay if it didn't. In the end I opted to install solar rather than get a battery, as I get paid to export and save money whatever happens to the price of energy. Octopus is making a loss right now on their EV night rate and that's not sustainable forever. The day/night differential is not something you bank on being available for the whole life of the battery, which is why I think you should install solar first and a battery second, if you have the means to do so. Also, if you have a hot water cylinder, you can divert excess solar PV energy into your tank using the immersion coil, reducing your gas demand. I plan to go gas free for my hot water demand, using the night rate to heat the water in winter and on cloudy days. And in summer mostly (hopefully) running the hot water off the excess solar.

What is your method of heating in the battery storage case? I may have missed it. I see that it needs either electric resistive heaters or heat pump or electric boiler of some type (e.g. ZEB). What is the installation implications for this as I understand your house currently uses a wet system. Great video to see your calculations. I find this subject challenging and there must definitely be space for some honest, independent, online comparison tools using input such as current gas/electric usage, number of radiators, square meterage of house, etc. I look forward to your update which will apply some of the missed factors raised in previous comments.

Very informative, the ASHP will have a 10yr lifespan and is not maintenance free, the batteries subject to chemistry should last longer and far less maintenance. Embodied carbon is a topic if being completely green is you goal and finally, continuity of supply, with battery storage you can technically with a bit more investment operate with the utility being off.

Hi Neil, I came to the same conclusions as you and have installed solar with 17.4kw battery storage. I have two electric cars and will also now switch to the “go green” electric rates as we now have a smart meter installed. I am also looking at a heat battery for hot water generation as this can also be charged overnight on cheap energy or from the solar panels during the day.

Looking into battery storage myself. I would need 14kw average. I've been quoted 10k for install. As an electrician I have friends who install so will see if I can get better price. Some problems are battery invert or can not power high demand items, plus ev demand could soon use up night time economy tariff. So apart from my solar putting some surplus into battery it's a big gamble.

Given your very high consumption of electricity (car) you really need to install PV asap to reduce this. Most people who install PV on their roof produce power when the sun shines and not necessarily when they need it but if you have a car to charge that becomes a lot easier to manage. Furthermore, if you had chosen a recent Hyundai or Kia you would be able to use the ~70kwh battery to perform the function of the Giv-Bat without breaking a sweat up to an instantaneous draw of 3.6kw.

Hi what size battery storage would you need, to have enough stored cheap night time energy to also power a heat pump during the day? maybe the trick is to have a good balance between both systems, in other words does battery storage make a heat pump more viable financially?

We have a 2014 Nissan Leaf with a 24 kWh battery. It's done 75k miles and the usable capacity is now in the region of 75-80% or 18-19 kWh which gives us a maximum range of somewhere in the region of 75 miles on a charge. With the recent crash in second hand electric car prices and the likely number of these older, lower capacity EVs which are on the road, I'd really like to see some sensibly priced tech developed where the battery can be removed from the car and utilised as storage for the home. A quick look at autotrader shows that a car like ours can be picked up for £3-4k. A home storage system with >10 kWh is likely over £10k at this point, and the market for an EV with such low range is going to disappear quickly. I have seen some DIY type systems cropping up on RU-vid but there's no way I'd be putting my house and family at risk by installing something like that. If we can find ways to repurpose batteries from older EVs for energy storage for other purposes, then this will provide benefits for all parties concerned.

You would save a good chunk of money just by switching energy tariffs to day and night rates regardless of having battery storage. Most EV owners are on these tariffs as it in pretty much all situations saves the bill payer money if they’re charging cars at home. As for the ASHP, you didn’t factor in the savings made from removing the gas meter which at your standing charge will be around £100 per year. Or the savings you’ll make in maintenance as ASHP require much less than gas fired boilers. All in all, battery storage is the better option especially if you factory in solar PV panels. You can even sell excess energy back to they grid at higher rates if you get the correct energy tariffs.

It would be interesting to see the co2 calculation of battery vs heat pump.

Thanks for creating this video, I'm really interested in a heat pump, but my house was built in the 1930s and has four chimneys, drafty floors and basic cavity wall construction (with no cavity insulation) - so would require a lot of upgrading before a heat pump would be suitable. One thing I thought of with your calculations - wouldn't your annual saving on gas be higher? You said you use electricity for cooking - so you'd also save the standing charge. It's not a massive saving, but it would contribute, and it's a saving you'll make from day 1 for the entire life of the heat pump.

It's crazy how expensive electricity is in the UK. Here in Quebec it's only CAD 0.07$/kwh which makes a heatpump the default most economical option despite the heatpump not offering as much efficiency in much of winter. With a high price of electricity, I'd consider solar as viable.

We have an ASHP and home battery installed. I agree with your maths - but the ASHP gets much more attractive when a home battery is also installed. My FoxEss 18.2kWh battery cost £7,500 (with a usable 16.4kWh) which covers 100% of my home demand in the summer - we'll see about the winter. I do think ASHP economics are muddled by the current (relatively cheap) price of gas. Even at a 4:1 COP, and ASHP is effectively delivering the same heat output as gas for a similar cost (because 1kW of electricity is 4X the cost of 1kW of gas) - so no opportunity to offset the high initial cost - but that changes with a big battery + ASHP.

Very good Video, Some points. Heat pumps are sold on a 3 to 4 times heat output per KWH, and under perfect conditions this could be the case, A test (under controlled conditions) was done and this turned out to be 1.75, i can't find this info at the moment, i believe it was done by octopus. The next problem, they need to run 24/7 due to the lower heat output, so if you haven't got excellent insulation it's going to be very expensive, and I like to sleep in a cool bedroom, and wake up in a warm one. And the maintenance costs and servicing need to be considered. Now the battery idea is excellent, as you have pointed out. The 6k you mentioned is about right, but i expect 2k of that would be the inverter and fitting. So i would strongly suggest spending 10k and doubling up on the battery, and if you haven't already thought of it fit a hybrid inverter so you can fit solar at a later date if you get the urge. I have been running 10kwh of batteries now for about 6 months and my only problem is, I wish I had 20kwh. The problem with all of this is predicting future energy costs, I see heat pumps in any environment as a big gamble, and can see electric at the very least 50ppkwh or more for the next 2 to 3 years, and gas at 15-20ppkwh, the wholesale price of gas at the moment is over 12ppkwh. Anyway best of luck.

A really useful video. One important thing to consider is the range of available heating options. I completed a self build in Cornwall 15 years ago and installed an air-water heat pump with underfloor heating in a concrete slab downstairs. Because of the level of insulation we only installed towel rails in the 2 upstairs bathrooms and the house was never cold, although we did run a woodturner on colder evenings, leaving the lounge door open so heat would naturally convect upstairs. We ran the whole house on economy 10 which gives 10 hours of off peak, including off-peak times in the afternoon and evening. It probably worked out slightly more expensive to run than gas, but that wasn't an option in our village so we were comparing against solid fuel, oil or propane making it a simple decision. 15 years on and the ASHP unit expired, just as we were agreeing a sale on the house, and had to be replaced - bad timing. Now I am looking at the whole thing again. We have bought a 1970's 2 bed semi in another part of the country - our son will be living there as we are working abroad for a while. I don't have any figures for current energy usage but, for me, doing nothing is not an option as the house currently has manually controlled storage heaters and an an old copper immersion tank with only an insulation jacket. The roof faces almost east-west so not ideal for solar and on a 2 bed house isn't huge anyway. Considering I have no wet heating system in the house at all, some form of solar system and/or air-air HP is looking like a promising option. Battery systems are fairly new to me but the figures seem to add up, particularly when combined with PV. Another option I have come across which may work for the house are smart a controlled water tank and storage heaters that automatically heat using PV output and cut down on electric usage over night. There is however the issue that most heating is required in the winter when PV output is generally lower. I'd be interested to learn more about the output that could be expected when installing PV on a less than optimal roof, and would welcome any recommendations for this particular set of circumstances.

Things become much more interesting to me when EVs and home chargers support vehicle to home. For our circumstances (vehicle only used on longer journeys on weekends so mostly idle during the week), that would help justify the cost of the car.

So for an old house, the saving for an ashp is not worth it because over its 15 to 20 yr life span as the average purchase price costs 5x more than a gas boiler. Is this a different cost on a new build with good airtightness and insulation?

If you don't have an EV solar panels and storage are a massive win at the moment. Agile export rates are as high as 18p throughout the entire day so a reasonably sized solar array (6kwp) can easily provide entire house consumption, charge battery storage bank AND also export to grid at around £3 per day. A heat pump wont be doing much during the summer months, whereas the PV and storage can generate money beyond the SEG.

just for comps. Our 3.6kw pv and 13kwh growatt install was £11,875 in june 2022 in the south east of UK

A question though - why doesn't anyone factor the standing charge when calculating the electricity costs. For example - I am currently on 28p per kwh. The standing charge is 43p. If my daily use is 7 kwh, then I would allocate the 43 p to the 7 kwh (43/7 ~6 p per kwh), so my electricity per unit costs me 28 + 6 = 34p per kwh. Am I doing it incorrectly here?

Battery storage makes sense when combined with solar. You forgot to calculate that you lose about 5% efficiency when you charge and discharge your battery (at minimum).

Great Video.

Maybes if you were building a house from scratch installing a heat pump would be a good idea? Combined with a solar system and battery storage? I would install a better inverter though, say 6kw. An inverter that can handle up to 6kw in and out.

Thank you I was going to get a heat pump as I have a gas combi system and my house is of similar size to yours and I have an eclectic car which I do charge only on off-peak electricity a power wall is definitely the way to go plus I am thinking of installing solar panels on my garage roof to charge the car as well and whatever leftover charge can go to the battery now solar cells have come down in price dramatically so I am going to fit 5 full panels to my garage get a controller fit it but not connect it I will get a specialist to do that and check over the system as I am competent in wiring 240 and 12volt I used to rewire houses with my dad who was a certified electrician I used to help him out on big jobs I always go above code as you can never be too careful with current so he will connect to the easee robot car charger as it's over a 1000 pounds for that unit and I don't want to blow it or void its warranty. same with the battery when I can afford to get it installed in my garage which will feed the house during the day I am at home all day as I am disabled now but can still do some jobs it just takes me a lot longer than before between rests. lol but I do believe it will save me a lot of money and when I can afford it get a small wind generator on the house roof to power at night and during the day as well helping me to get off the grid and finally get a company in to install solar panels to the house roof with another power wall so two power walls and then I should be able to stick the fingers up to the power companies and tell them to shove it the robbing you know whats, LOL. no not really I am too kind but I will think it as they are robbing us blind to keep their shareholders sweet it was the worst thing the conservatives ever did was to privatize the utilities of our houses power and gas and water biggest mistake ever this was predicted by Enoch Powell and everybody laughed at him now whos laughing they all said he was scaremongering well here we are now I never liked the man but I respected his views and I could see what he was saying way back then and all that he said has come to past I really wished he had got it wrong boohoo.lol bye

How things might have changed with electricity price rises. But My experience of using an EV tariff plus a an ASHP is that for 5 months of the year no daytime electricity is used for heating and hot water. And indeed for most of the year the heat pump runs hard overnight, lower COP because it is colder and the savings are much higher than your calculations. Pair a heat pump and a battery and charge your car overnight and it is a win, win, win situation.

The heat pump if installation is done by a good experienced company you should get 4.5 kw per 1kw of electrical power in . Also with the current gas situation and the fact it's carbon free and gas is only going to go up and installation costs will it's best to get one sooner than later 👍

Very interesting !.

That battery sounds small. We started w 5kWh of battery, but it would not sustain the microwave and Induction hob simultaneously. We're now up to 20kWh of battery on a 5kW inverter (Growatt), which seems to be doing the trick.

Wow those bills are quite big ! One word of caution ... How long is cheap night time electricity going to last ? With people charging EV off peak , the demand for off peak electricity will rise & the discount go down.

Don't you get RHI (renewable heat incentive) for the heat pump? Does that change the calculations?

Great video thank you! Remove the discounted overnight tariff and costs don’t really work :(. The only way this is really viable is if we get massive wage inflation and cost of energy does not go up much - unlikely.

Problem I have here in the Netherlands is that the ‘night time’ tariff = 0.32 euro while the normal tariff = 0.38 euro. So the gap isn’t large enough for this type of installation.

Solar and a battery. Mini split heat pumps. Small water heater since you are space heating with the mini split and won't need as much hot water possibly powered by the solar panel system.

Thanks

Or perhaps instal a larger battery and perhaps PV panels (as you rightly suggest). Use the PV panels to power your daytime needs and any excess to top up the batterys during the day. Then, if you have a large enough pack, as I do, power your ASHP from them. So now your heating is

Interesting video. I myself have been doing some of this same research for much the same reasons as you. In actual fact, your savings could be even greater if you carefully shopped around for the battery. GivEnergy is very good but I've found that Pylontech are very well rated and have performed better than all other batteries on the market in stress tests and are cheaper. A 14KW battery system is the same price as the 8KW system (installation not included) but it can be stacked to provide up to 120 KWh storage (if anyone ever needed that much). So, depending on what your daily power output is, it is conceivable that you could meet your entire daily power output with cheap energy that you stored in the battery overnight. So you're effectively only ever paying for cheaper (overnight) electricity rates. Using your current costs, if you could do this, your savings would be around £2238 annually. Of course, the cost of the system would be higher so your payback time won't vary much but after it's paid back your gains have increased. Incidentally, you could presently charge your car overnight as well as run your dishwasher, tumble drier, washing machine overnight. Most of these devices should have in-built timers so there's nothing to stop you doing this without installing a battery. By the way, I'm in no way affiliated with any of these companies and am just basing this off of my research - which may well be flawed. As with most advice on the internet, don't treat it as gospel and do your own research to see if it fits your needs 😀

If your car supported V2G or V2H you could use your car as an alternative to your battery or have a smaller lower cost fixed battery (assumes you WFH for the majority of your time).

will the battery charge with cheap power and discharge when expensive power?

Hi Neil, I’m coming to the same conclusion myself… the heat pump is more about saving carbon reduction than money. Just wondering why you haven’t bothered with a dual tariff for the EV before?

Based on over 20 years as a Gas installer, over 70 heatpump installations (new build and retro) and living off grid for electricity for the past 3 years. There's not a cat in hells chance my Newbuild house will have a heatpump, if I'm "forced" to have one to tick a box, it will be "borrowed" box ticked and returned. Solar & batteries can realistically give you 100% of your domestic power for 8 or 9 months of the year, the rest you cover with mains or genny, my annual red diesel bill ( for 9kva genny) is way less than the standing charge for mains power.