Heat Geek Mini Store: Is It a Good Fit For Your Home? 

Hi Szymon. A good well balanced presentation. Someone questioned your objectivity in the comments which I felt was unfair. I like to see balanced review that points out the possible drawbacks as well as the positive points and you absolutely nailed this. E.g You questioned performance in the winter which was one of my immediate thoughts. The SCOP was compared with the large cylinder and "managing expectations" was mentioned. It might be nice to have some figures on the various scenarios you demonstrated at some time in the future in both the summer and winter conditions. Finally, I learnt from this as well (new to heat pumps). It all well and good doing the theoretical courses but the practical applications you demonstrate are invaluable. Thank you

A test showing how two of these could be combined for a larger volume/more economical performance would be good. I have two ‘blind’ corners in my kitchen that they could go in.

Well done Syzmon - excellent practical analysis and demonstration. I think your caveats will be completely overlooked/ignored by the critics. In sum this is a practical alternative for those who absolutely do not have the room for a conventional unvented cylinder of a capacity suitable for the dwelling. If one has the room for a conventional cylinder then deciding to fit one of these means you are accepting all the performance and efficiency compromises that come with it.

Great video, as always. Nice to see another option become available. Just like every other technology, as time goes by, more options appear, and costs go down.

Thank you for the video. Looking forward to the winter tests.

Great ballanced video, im suprised by the number of comments that have missed the fact this is the smallest in a range and larger devices that exist and should be used for larger properties. Sounds like it would be fine in a tiny flat with only a shower but if you want a bath you are going to be compromised, try to fit one of the bigger versions. What is the best strategy with these, fit the largest you can?

An ideal partner with a thermostatic shower & waste water heat recovery? A further bonus is no legionnaires cycle needed as the water is direct

Try it with a waste water heat recovery unit may get some extra duration of hot water flow

Any recommenadations for low flow shower heads and where to get those flow restrictors?

love those steampunk polished brass pipes... this setup is practically a work of art. please come do the plumbing in my condo

Great test with a really clear explanation of the pros and çons, thank you

If there were 10,000 people like you and the other Heat Geek assured installers, we would be well on our way to reaching the UK's target for ASHP installations. Three years back I installed open vented, indirect, 600x300 high recovery cylinder on a 12KW Glowworm energy boiler, they only had three hot water taps and an electric shower, the boilers on 24/7 for hot water on a Glowworm weathercomp system, the three of them in the house cannot get it to run out of hot water or run below 45 degs. Once people have had a high recovery cylinder fitted they love it, it always has hot water like a combi boiler if hot water priority controls are fitted its very fuel efficient, what more could you want.

Why don't Heat Geek folks ever mention heat batteries from the likes of Sunamp? Solves the same problems that the Mini store is trying to, but can store way more heat in the same/less space.

What's the performance like between the Mini Store XS and the Mini Store TALL? The tall having a capacity of 110L, would it be more efficient?

What about the temperature of the space heating in winter? Does it drop a lot when you puncture heat for the mini tank for long bath? Can people feel it in the house? Or is the inertia of the building act as the buffer?

Honestly, I think we need to rethink how we design shower enclosures. If they were enclosed with minimal air changes, the amount of heat you lose to the rest of the bathroom would be significant. Also, integrated hydronic heating panels would help. Low flow isn't an issue if you're warm.

When ever possible use a full size cylinder, much more efficient. If ready no space at all maybe consider a minstore, but also think about direct electric water heater ( after the ministore?)

This needs revisiting in January tbh.

Further details about the Heat Geek Mini Store can be found on our website.

In the situations like a flat wouldn’t it be more viable and simple to stick with an electric shower? Possibly a small under sink water heater for washing up / basins. That removes the need for any stored hot water and prevents the cycling of the heat pump on its CH. you can always upsize the shower for a better flow rate. Unless im being thick as usual. Also I didn’t expect you to have one of those shower heads 😂

How many outlets can it run at the same time?

Thanks Szymon.

Bit concerned this could result in people being put off heat pumps even more. It seems just about good enough for a reasonable length shower at an economy that is somewhat worse than gas - as you can't choose when to recharge. I really struggle to see these as replacements for combis in all but small flats without a bath tub.

Another good video, can also see uses for this with a gas boiler in areas difficult to get discharge pipework to outside.

hmmm maybe a good idea for a single person or under sink tank with main elsewhere to get around flow rate s not affecting the main shower etc, , but for a family a definite miss, further more just 5litres per min even 10 is quite slow given existing gas and 140litre can flow typically 20 literes with a 22 min recharge on 25kwh its going to be tough sale, convincing customers who may be migrating, i would still stick with a higher capacity cylinder with 50mm with a heat pump

A small storage tank is the wrong solution for pairing with a heat pump, but fine with something like a gas boiler with an output 12 kW. The boiler can recover at the rate of 4 litres/minute but the lower power of a heat pump, perhaps less than 7kW in winter, means that recovery is down to about 2.3 litres/minute - insufficient for peak hot water usage times unless you are a one-person or frugal-two household. With 3 beds, design for 4 people, assuming that 200 litres is needed in half an hour (4 showers or 1 bath and 2 showers). Multiply your recovery power, 7kW in this heat pump case, by 10 to give the recovery in half an hour. That's 70 litres for this heat pump. So the storage needed = 200 litres - recovery = 200 litres - 70 litres in this case = 130 litres. If you've got a 12 kW gas boiler, recovery is 120 litres in half an hour so storage required = 200 - 120 = 80 litres. (Priority Domestic Hot Water is, of course, needed.) If' you've got a 30 kW combi, that will provide 300 litres in half an hour, you need no storage. But, as the article says, shower design is important. Drench showers, the current fashion, can use 15 litres/minute and demand wastefully large hot water systems. Aim for 6 litres/minute. the current recommendation for government buildings. Your teenage children will indeed spend 10 minutes in them, consuming 60 litres each.

Thanks for your time spend on testing the Ministore. During the tests did you come up with any correlations between DHW flow, store high limit temperature and the size of the vessel to use as kind of formula? Do Heat Geek guys have any, as Newark guys do not. I have spoken to Adam B. from Newark and not only ordering now any Thermalstore cylinder/buffer it will not be ready before mid November but also they have no data or a solution how to calculate the variables to make a right choice. Let's say if you had double the size of the vessel(or triple) how that would perform? I like the idea but I don't want to order now to be able to start testing the cylinder in mid November to find out if my choice was the right one, to fit it for the customer after all. Finally if the customer have a space for DHW cylinder would you still fit one (Supercylinder) or have gone for Thermalstore to eliminate the G3 regs and Water regs in terms of Legionella Great work Simon😊

Great video Szymon, I seen on your sensocomfort you had legionella cycle off, do you think it’s pointless to have this activated in domestic property’s with a correctly sized cylinder.

Surely, the best option would be to do away with the cylinder and install a full size ‘thermal store’ where you have the space. You could then heat the store to a higher temperature and install a blending valve on outlet. You would need to ensure high insulation factor on thermal store to maintain as high a temperature in thermal store as possible. As it is not unvented, no G3 qualification required

6:55 Does that showerhead really does what their commericals promise re. the beads cleaning the water? And does the housing get dirty/cloudy?

I have really enjoyed watching your videos especially those about heat pumps and systems like the mini store. However, we have two properties; a 1930s listed flat in central London where we can't install a heat pump and a small 1br cottage in the country where there is only electricity (an electric shower & 3 radiators) but I'm not sure the cost of a heat pump and tiny cylinder makes much financial sense. There must be hundreds of thousands of flats and small houses like ours, but every video about this tech never addresses the challenges of listed properties or rural ones where there is not even any signal for a smart meter.

But this is the smallest one in the range (60L). For a typical semi, I'm more interested in how the larger ones (110L) perform compared to the Heat Geek/other cylinders which start at 150L. A cylinder about 1m tall is better than one about 1.5m tall if it can fill a bath and give a decent shower.

If you have a medium sized house and need capacity for regular baths and consecutive showers would two mini stores in two separate locations be a viable solution if there's no room for a full size cylinder?

I did not understand why you have less pressure than a classic DHW boiler? You should have the pressure of the domestic water network (between 4 and 10 Bar in Switzerland). Is it because of the pressure drop of the large heat exchanger inside the cylinder? Or is the pressure vessel tank with the larger boiler works as a sub-network increasing the observed pressure?

Thank you for the video. I am curious about what you think about the Ministore FAT which is seems to ideal for going under a cupboard, and whether that will do what is needed for us. Deciding tonight whether to go for the ministore or a Mitsubishi which my installer is pushing. The FAT has nearly double the volume of the model you were suggesting does that resolve some of your concerns?

great video. is that app available for other heat geeks to use ??

genuine question , why not just install an electric shower and instantaneous water heater for the sinks, or would that use more energy

As a refrigeration tech I'd advide highly against "setting your anti-cyle to zero". Thats a fast track to compressor failure.

How much better performance would you expect if fitted with a 12kW Arotherm plus?

Looks like you need to get in touch with the Coolgeeks as well! Looked like you were sweating your balls off there up in the office!

So if you move to the next size up should be fine ?

So every time you use hot water the heatpump needs to turn on? Doesn't sound too good for the pump...

Any plans for a cylinder with a condenser inside, to be used with otherwise A2A systems?

Thank you for the video. I liked the idea of the mini store, i thought it could work for me as have a 3 bed house with varying demend for hot water (currently on a combi). 40% of the time its just me but the other 60% of the time have 2 children here using lots of hot water. I'm thinking the 130l version might be better for me, but of course the reheat time would be longer, so maybe then i'd be losing the main benefit of the store? Is the scenario for the bigger stores they they would be paired with bigger heat pumps? Ive done heat loss calcs and its close between getting a 5 or 7kw vailant so maybe a 5/7kw would just take too long on the 130l one?

For me this is too far into "managing expectations" - although I can see the utility of it for eg pre-heating water going into the cylinder at night or something to that effect. It might not run a whole bath, but it can be supplementary heat

Can a Mini Store work with a gas system boiler if so what are the advantages?

My showers do not use 3kws a day you. 2kw electric shower would be adequate, mine has a 0, 4 and 9 kW setting and the temperature dial is actually a "flow" dial... Because lower flow is higher temperature for a given power... I actually have to constantly switch between 4 and 0 to get the temperature at the modest flow I want, so a 2kwh shower would be better. I only need as little as 5lts, can be more if wanted but not needed. I can't believe you just assume people need 3kwh a day to shower. I only use around 1.5kwh a day averaged out for everything. I even converted a chest freezer into a chest fridge which is way more efficient for basic refrigeration needs just because it opens at the top not the side.

Hey Symon. So its not about the design or install If it doesn't pass the wife test then it's too much a risk 😆

I hope you're being objective seeing as Heat Geek is your mate!

Unexpectedly negative review given the awesome potential of this thing. If you want a higher flow rate for a shower couldn't you just make the immersion do more of the work? It also seems this would work well with a waste heat recovery unit on the shower to enable a higher flow rate. Like you say its not as efficient as a full size cylinder but this is the first option I've seen that would make me want a heat pump in a flat. Combi boilers rule in flats as space saving really matters. I'm always amazed by people who haven't ripped out their old cylinders / system boilers.

Everything I see on heat pumps suggests you need to be a technical geek always adjusting things to use them. I want to replace my storage heaters with modern high heat retention heaters. The company contracted under the HUG scheme are suggesting a heat pump. I'm dubious because its all so complicated!

Not convinced. If it had an ideal badge on it we’d all be laughing our heads off at it.

This is nothing new, Gledhill have been doing this for years

Sounds awful to be honest , 5 litre per minute in a shower is lit getting peed on.

seems like a lot of kit installed to get rid of a gas boiler.... strange?

Let me guess the fancy pink cylinder its another thousands pounds on top of all the other thousands you've spent, just to still not do as good a job as a 10 year old combi boiler?

Ballshit baffles brains. Heatpumps working over 35 deg become way less efficient. Install cost is high. Electricity is more expensive than gas. Electricity to run is from the supplier which is from a gas or coal generator. What's the point? Electricity run over power cables drops massively and is inefficient. Hydrogen in the form of a cell is way way more efficient. Please push that technology as a smart guy and inovator. I have faith in you. Green Hydrogen is cheap in hot countries but that will hand power to them. Please push technology not politics for humanity

14:14 You meant to say "half the efficiency and double the running costs", right?