Passive House - Fresh Air System Install & Costs (Zehnder) 

"𝘐𝘯 𝘵𝘩𝘦 𝘯𝘰𝘳𝘵𝘩 𝘪𝘵'𝘴 𝘴𝘰 𝘥𝘳𝘺 𝘪𝘯 𝘵𝘩𝘦 𝘸𝘪𝘯𝘵𝘦𝘳...𝘴𝘰 𝘸𝘦 𝘩𝘶𝘮𝘪𝘥𝘪𝘧𝘺 𝘰𝘶𝘳 𝘩𝘰𝘮𝘦𝘴" That depends on where "in the north" you're talking about. Much of New England/the Mid Atlantic or the Pacific NW states have pretty high average humidity in winter(often over 70% in the morning). The average humidity in Chicago is actually highest from December through January. When I still lived in NJ my dehumidifier ran year round as did the one in my grandparents home near Newark NY. Humidity levels are influenced far more by things like terrain, altitude, large nearby bodies of water(Lake Michigan or Ontario for example) and other factors than they are simply by latitude.

@@CzechSixTv that's relative humidify Einstein. Go back to school pal.

@@CzechSixTv Chicago's highest dew point ever recorded was 83°F on July 30, 1999

@@CybekCusal It obviously wouldn't make sense comparing extremes such as 100% humidity at -20 in Fargo to 60% humidity at 45 degrees in Atlanta simply because the measurements were taken during the same season or even month. I'm talking about humidity levels at similar temperatures. It doesn't matter how you slice it. 65-70% average humidity on a 30 degree day in Chicago or a 35 degree day in Seattle means there is physically more moisture in the air than there is at 56% in Amarillo TX or 50% in Sedona AZ at the exact same temps. That humidity difference is why 30 degrees in Chicago is absolutely biting compared to 30 degrees in those areas of the southwest I mentioned. It finds its way into poorly sealed older homes in those areas, lingering in wall cavities/basements/crawlspaces, condensing when temps drop at night leading to problems down the road. Does that winter humidity compare to Mobile Alabama, Nawlins or other gulf coast cities at any time of the year? No, but few places in the US would. What do Seattle, Chicago or Boston have in common with those gulf coast cities though that Amarillo, Sedona or Death Valley don't? Immediate proximity to giant bodies of water that stay warm for some time even after the air temps start dropping. When comparing apples to apples, latitude only plays a small part in humidity levels.

@@CzechSixTv what you say is incorrect. You are going to hurt yourself. HVAC isn't your thing. Dew point represents the moisture content, not relative humidity. Go play with Legos.

Ballpark numbers was the difference between “the average homeowner could never afford these high end products” to “hey I’m an average homeowner maybe I could save up towards that”. Gotta change the stigma!

I’m breaking ground in a month, I like the idea of this. However I bet Matt’s HVAC would cost me over $40k. I need sponsors.

@@markseamans4682 I will sponsor you.

@@jgoody7467 haha!

@@markseamans4682 way over $40k. It would likely be $50k+ plus builder P&O and Supervision. So $65-$75k. I spoke to a builder recently who put in a very similar system on a job to this, but this is even higher end.

Just installing 10 normal point of use exhaust fans and ducting in a house that size will run you $2K (for the cheap stuff builders love to install) plus the headaches that come with it.

How do you clean the semi-flexible ducting?

Giles B they are smooth inside duct cleaning machine for small ducts

Filtration and Maintenance ever 3 months at the HRV/ERV will help keep the supply air clean

@@Floreypottery thanks, I've got a few 90 degree bends but mostly on the extract ducts.

You cant get mold because of the MERV13 filtration at the entry point and than MERV15 on top of that.

In situations like this, it's hard to know if they suck, or if they really blow! 😁

They all have option to be installed independently

no kitchen exhaust in this house. Induction cooktop, so it's not needed. He just puts a return grille in the kitchen as part of this ventilation system instead

@@kevinmacnichol7692 Even without gas cooktops, I'd still want additional kitchen exhaust to handle smoke and smells from cooking.

@@kevinmacnichol7692 An air return in the kitchen is a code violation by the way. And the need for a kitchen exhaust is not based on the type of cooktop but rather for the heat and moisture that is generated as well as the occasions burned food when the cook is not paying attention. Or are you just trolling with the obvious misstatements?

@@BubbleOnPlumb tell that to all the crappy luxury apartment units. Staring at the return vent in the kitchen right now.

Just 1 solar panel of 400 Watts can run this system for 10 years or more for free (after the cost of solar panels, Battery, and control system) and still have some extra energy to spare. He said this big system would use about 100 Watts, so about 2,400 Watts a day. The average day is exactly 12 hours, the power you actually get on your panels is equal to about 6 hours of full sun radiation per day. Therefore 1- 400W panel (or 4 - 100W panes for lower price but need more space) would create 400Wx6=2,400W a day. Now, this house has a great large open space for multiple arrays of solar panels systems and since his whole house is running on electricity He can practically run the entire house on solar. He does not even need a battery backup and connects the Panels to his Electric Miters and the power production would be subtracted from his Bill. In some states, if u produce more power than use they would even pay u for the extra energy u give them. Now since he lives in Texas a really hot n sunny state his power production would be even higher, so I would have a backup battery for emergencies since Texas Power System SUCKS! WHY THE F***!!! Texas is the only state in the country that is outside the National Power Grid?

@@nicolascardillo7615 an average day on my planet (called earth) is 24 hrs…

I was thinking the same. However, TOH would have added a light to the dark attic and had smoother camera movements, I was getting nauseated from the shaking.

like fake news etc lol

That’s the point

Shawn, you are absolutely correct. Thanks. There is no "zoning" on this ERV air distribution system. We did review this together after filming, but the note got missed in the editing.

Actually I’ve been testing a Miele heat pump dryer and it’s pretty amazing. Perfectly dry clothes. 45 min run time. No vent to the outside!

I have a Bosch electric condensing ventless dryer. Works great, love not needing a vent.

@@buildshow Hi Matt, I'm in the process of self installing a heat recovery system in the UK. Your price estimates are about the same here too. I've also had a Miele heat pump dryer for 5 years in a small utility cupboard stacked ontop of the washing machine. It works billiantly but I decided to put a dedicated heat recovery extract vent in there to remove the slight tumble dryer smell of hot clothes. Even before intalling MHRV, I liked the fact that I wasnt wasting energy blowing hot air outside.

James Gleason because extra venting work equals cost of equipment and builders time! All saved by not having to need to vent a dryer.

@@JamesBlazen Switzerland has outright banned vented dryers since 2012. Heatpump or electric condensing dryers are the way to go. Heating up air and then blowing it through clothes and then right outside is very wasteful.

It doesn't tie in. It completely replaces any bathroom exhaust fan.

@@retartedfreak Does it also replace the exhaust fan in the kitchen or is this separate?

@@wkellander i would think it is separate. IDK 100%.

Matt does a minor explanation from 4:20-5:25, and the installer guy explains it at 11:20-12:00. Basically, bathrooms, laundry room, and kitchen that would normally have exhausts/vents/etc will channel through the one "exhaust out" 8 inch duct that is part of the system.

@@trinity1aee So all that greasy air from the stove vent hood is going through that filter that protects the air exchanger from gunking up ? That filter would need constant changing, unless there is another filter in the range hood itself. Also, is the ERV fan going to be able to keep up with a 900cfm stove exhaust fan when it was designed for just 180cfm ? I am pretty sure a stove vent needs to be metal, so those plastic hoses are only for supply fresh air and the exhausts from kitchen and baths are all traditional metal ducts ?

Gas heating is far far cheaper than electric and likely more environmental too depending on the source of your electricity

Thank you for that...good info.

yes - microwave with built in "ventilation" are a joke. I put a real hood in over my cooktop an the difference it makes is amazing. And it's not that big a deal to crack a door to get enough makeup air when it's on high. I probably should have some sort of a make up fan but I'm not staying in this house long term and I certainly won't get the investment back. Having sold houses in the past when moving most people are beyond clueless when it comes to infrastructure - all they care about is move in ready :p

Matt is not venting the kitchen hood through the ERV. You're correct...we DON'T do that! ;)

10 months later, I just got a quote from my local Zehnder distributor for an upcoming basically Passive house build. Thanks again Matt for the video!! Next on the list, EAS windows.... Here we go!

Jeff , I think the concept is for the positive room to push air through the negative pressure rooms where you want to exhaust. Such as the bath rooms, kitchen and laundry room. So instead of one return, a house has many, an equal amount to be accurate. This would stop wind tunnel effect in poorly balanced homes. What I cannot see is can you still create AC/heat zones? I want my office to be cooler than my gal wants her craft room.

These airflows are relatively low compared to heating and cooling. The systems operate independently. And the pressure differentials between rooms are enough to change the air, but easy enough to flow around/under closed doors. Supplying fresh air to bedrooms and living rooms and extracting from wet/stinky rooms keeps the air in the whole house clean without any noticeable drafts.

40 watts/h. Yes if your ofen has a secondary wir from outside by pipe. And normal Filter need 2 20€ /pair

lol 250m2 is huge, this is probabaly made in china already.

I second this.. I'm also interested in your kitchen vent set up. I was thinking of just having a smaller hood vent and fan for an induction cook top but if I can avoid it with a system like this then thats a massive plus. I want my house to have minimal vents due to being in a wildland urban interface (high fire zone). For the dryer I'm thinking of having a vent installed for future proofing but sealed and use a heat pump dryer. I'm curious if you are doing the same. Thanks!

Great question. I wondered the same myself. Surely there has to be a seperate system with a damper.

@@mtscott Most hoods will have filters that catch most of the grease. But a well designed kitchen will have its own makeup air system for tho hood. It doesn't have to be an expensive set up, just a powered duct fan system that brings makeup air in around the bottom of the range. They have solenoids that turn the makeup air supply on when the hood exhaust is turned on.

This was addressed in a more recent video. The range hood is *not* connected to the ERV/HRV. Besides the oil/grease issue, there's just too much air. High flow range hoods do 600-800 cfm. Matt's ERV is under 200 cfm, so it would never be able to handle it. In his house, he has an intake fan (with filter) to balance the range hood, that's powered when the range hood is on.

See 13 minute mark in video, he discusses exhaust.

I was thinking about the same thing, but you'll have those exhausts at each bath, range hood and whatever else you need vented.

Thanks Pete!

Where do you get your supplies, from?! I was planning on a retro-fit into an older house here in Quebec, built in 1985, that the guys installed an Air Exchanger in the Attic! I have been looking around to find either someone to give me a cost run down or DIY this thing, but can only find the box store HRV/ERV's and they don't look tempting at all!

@@FelipeSQ04 entry level hrv from venmar, aldes, lifebreath, any hvac company can install those at around 3000. The suppliers doesnt sell to normal people but at Canac, you can get the nektra and its basically a lifebreath

@@SpecialKthx Thanks a lot, I had read that some places only sold for hvac companies, so I thought it made sense to confirm with you. Will try to go through the Renovert program to make this change, since right now the air exchanger in my home is in the Attic just pushing winter cold air inside :D Thanks a bunch!

@@FelipeSQ04 I suspect you have a asthon or a venmar econo/pro If you have a 2 story house it will be more complicated but a 1 story with basement not finish or with removable tiles will be easier. You might have to sacrifice a corner of a closet tho.

@@FelipeSQ04 you also can check www.epurair.com/en/products/. They are Quebec based company and produce good quality residential ERVs.

Sounds like this would eliminate the standard trunk and branch system. Just a different type of cleaning.

You'll need to invest in a couple of 3 inch (75mm) brushes. ;-)

Not really. Why would you clean the exhaust ducts?

Good question, James. The fans can be set to be positively or negatively balanced up to 15%. The advantages/disadvantages vary from one climate to another. Also, you can temporarily turn off either the supply or exhaust fan.

While this is a useful calculation, you need to pro rate the cost of the system and the maintenance of the system over its life. Additionally, if you're considering putting this in an existing home, what are your cost going to be to make the home tight to take advantage of the system.

Minus the cost savings what would be the delta? still cost (- out of pocket) or benefit (+ in pocket).

Yea that's a great savings but what the marketing wank and builders don't tell you. The huge upfront investment to buy it and the high cost maintain/ repair them you WiLL NEVER makes your money back. I work and install these systems daily and I would never want this in my home or a ultra tight home. Cost of one of these systems I can buy 2-3 of a high quality mid range efficiency system that doesn't break the bank to repair or run. I can actually make my money back

it's better than the audio normalization :)

Yes, this one my biggest pet peeves - these are expensive-to-design ($3-$5K), expensive-to-install (these complex HVAC systems can easily run $50K) and expensive-to-maintain (filters cost hundreds every year - IF you even know they need to be replaced). These are 1%er systems or virtue-signalling systems, not Average Joe Homeowner systems. Granted, Matt's audience isn't Joe Homeowner, but it bugs me that there's no acknowledgment of this - despite the cost consistently being a major concern in the comments.

@@krinohs I'm lazy by nature. If it is hard to get at I'm going to put it off. Having a beautiful system in the attic means to me out of sight out of mind. Also if I followed all of manufacturer service intervals my life would consist of nothing but work and servicing all my ______ and sleep. Ps. It is wed and I'm going to hit my 40 hours in about an hour and I have alot more to get done before Sunday. This is more than normal but not out of the ordinary for me or my co-workers.

@@krinohs You seem like a fun person.... You ever heard of a joke? Yeah, I know how to, and, more importantly, do preventative maintenance on my major appliances. I was just making a J-O-K-E about it - Because there are people who would do it.

​@@ArthurDentZaphodBeeb Interesting that a system like this is considered "exclusive" or "for the rich". In Estonia (where I live), heat recuperating ventilation systems are pretty much standard for every new apartment and house built, irrespective of the cost of the place. You pretty much have to install them if you want to meet minimum energy efficiency requirements. A lot of these systems actually come with control units that will remind you when to change the filters and it's more like once to twice per year not every quarter. The filters themselves are usually between €20-30 so you're looking at maybe 20-60€ per year in filter costs, depending on how often you change them. What you get in return (at least in a cold climate) is huge savings in heating costs because most modern systems are at least 80% efficient, many have an efficiency rate over 90%. A house or apartment building with natural ventilation will lose 20-30% in heat via exhausted air. Even old apartment buildings that are being renovated will have heat recuperating ventilation systems fitted. You can watch a Zehnder system being fitted to an old apartment building here: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-9MvpRtf9Pqg.html

@@krinohs thanks for winning a bet between my wife and I. I said I can say 1 thing mid comment say something else and someone will call it out. I got lunch out of the deal, So thanks

I started reading the comments because I was curious about all the bathroom moisture that is typically exhausted outside will now be allowed to transfer to the supply air in @mattrisinger ‘s new house since it’s an ERV and moisture transfers. Am I understanding this correctly?

Approximately 14:15 the guy states the air is never recirculated, it goes outside.

@@Gamerz00760 That's correct. They're in Texas. But in cold climates you have to recirc or it will freeze up. During the recirc, it is not intaking nor exhausting. In -30 celcius winters such as Canada, recirc is a must to prevent freeze up.

100% agree

most of that cost is for stuff *other* than the unit. zehnder accessories are pretty expensive. the q600 also has a maximum capacity of close to 400 cfm, which is probably several times greater than the maximum cfm for your fantech system. there is also a lot more intelligence in the q600 than there is in the fantech. for example, when the zehnder person in the video said that the tubes were 12 cfm each, he didn't actually know that - it's just a talking point number. the only way that that would possibly be true, is if the total equivalent lengths for all tube runs were the same. the way it works is that you just throw the tubes out there, and you rely on the intelligence of the q600 to figure out the best way to distribute air to them. so they are counting on the q600 to do a kind of automated "manual d" analysis. what they call "commissioning" sounds like a "manual b" type of analysis; it's the kind of thing that you should do in any forced air system.

@@paperwait9611 100% right.

joe rond well I have the SHR 3005r which is rated at 267 cfm. So yes it’s lower cfm, but why would I need more when I rarely run it above low speed anyway? So I could install 2 for less than $4000 total, and have over 100 cfm more. If I wanted, but I don’t want or need. My unit on high can exchange all the air in the envelope of my home every 2.31 hours.

@@christophergruenwald5054 if you're happy with your investment and quality service etc. please enjoy your house.

Same question here.

Matt always does this in his builds now. I’d be shocked if he wasn’t running a discrete dehumidifier as this system isn’t really intended for dedicated dehum.

Of course, he is putting all of HVAC+D separate hahaha.

@@CompCrasher86. And it isn't connected to the "H and AC" part of the air system. (A downside really - it should be plumbed right into the dehumidifier input to the recirculating ducted Reverse cycle AC.

I want to see how heating, cooling, and de-humidification is all tied into this system too. I'm not quite sure how those pieces of the puzzle fit together.

that's what I was talking about lol !!

I’ll have a separate system for the kitchen exhaust. I’m using a heat pump dryer so I won’t need a vent

@@buildshow Any particular reason why the kitchen exhaust isn't being integrated with your Zehnder system? I'm very curious how these ERV/HRV systems can integrate that exhaust since they typically require a substantial flow rate but only when called upon. I like the idea of one exhaust penetration for the whole house, I'm just not quite sure how that can be managed with these systems. Also, how are you managing the evaporated moisture from your heat pump dryer? I would think you would still need a vent for that. The heat pump in the dryer is only a heat source to facilitate evaporation of moisture from the damp items within it. Also,

@@buildshow even if you had a dryer vent, the q600 can adjust supply and exhaust rates in response to the dryer exhaust. by not having a dryer vent, you are putting a big humidity load in your building envelope, and the zehnder system shown does not provide humidity control. so you would have to have mechanical systems (force air conditioning and/or dehumidifier) to provide humidity control. some people go for a recirculating hood, but a kitchen exhaust is going to work better. i have a heat pump water heater and considered a heat pump dryer but concluded that it really didn't do much and was pretty much a waste of money.

you definitely don't want the kitchen hood tied to the dedicated outdoor air system. the grease and residue from cooking would gum up the ducts and the filter at the erv. you don't want the dryer vent hooked in either because the filter in your dryer does not capture all of the lint. the only things you want going into the return ducts of the doas are odors.

@@paperwait9611 You make a good point about dryer lint. That would inevitably build up in the ducts, except the Zender duct tubes appear to have a smooth surface finish and the interface with the manifolds also appears quite smooth. The manifold boxes could be problematic though. Not only is there particulate in the dryer vent air but also a lot of moisture and don't forget heat. In the summer time you would not want to transfer that heat to your supply air which an ERV/HRV would do; you'd be fighting your AC system with your ventilation system. The moisture transfer could also certainly be problem if you don't already have a dehumidifier in the system. Like you said an ERV is not a dehumidifier, unless of course the exhaust air has a dew point lower than the incoming air, then the core would condensate...there is a degree of humidity control inherent to an ERV since enthalpy accounts for both sensible and latent heat. Regarding the kitchen vent, presumably regardless of direct vent or tie in to a residential DOAS (i.e. ERV/HRV) a grease filter should be present. Recirculation vents do not adequately manage odor, smoke, or steam... they have very little benefit at all frankly. That said most kitchen exhaust hoods call for 150-400CFM would could be equally just as large as the ventilation needs of the house. So do you upsized the DOAS to include the kitchen or accept the needs for another vent? Kind of seems like you really need three vents to avoid any problems Kitchen, Dryer, rest of the house. Problem is the DOAS would need to compensate for the Dryer and the Kitchen exhaust with supply air, so you'd still need some kind of tie in or dedicated direct air inlets for those areas, but then you lose efficiency by not tempering that makeup air.

Nope, didn’t cover my passive solar home in CA!

I was just thinking that. 30k system to save $20 a month and replaced after a few years? First world solutions

@@jl9678 where did you come up with 30k? he mentioned 10k, but that is for a pretty large house

@@BrianKrahmer 10-12k is just the equipment package. If I know anything about hvac it's that the labor is usually 1 to 2x the equipment price. Hence the 30k

@@jl9678 if you're willing to pay 20k to install a system like that, drop me a line. i'll fly over from europe just to do that. at a labor rate of $100/hr, you're talking 5 weeks of work. i'd be disappointed if i couldn't install that system in less than a week. i'd honestly estimate 3 days

Add some solar and over 20 years the costs go away - then we may need to replace the solar - at costs equivalent of a new AC unit. (Thinking about it - HVAC will likely never have a similar warranty to solar panels, so the solar is probably a better complement to "zero net cost")

Good points, Colin. An ROI could be estimated using specific flow rates and temperature differentials as long as you're comparing it to the same ventilation rate using bathroom fans (have to compare it to something). We have examples of this we could share with you. But the reality is that most homes are very poorly ventilated, making the ROI on heat/energy recovery difficult. And beyond that, attempts are now being made by health researchers to quantify the lost productivity and medical costs that can be traced back to poor indoor air quality. Should that be part of the ROI?

@@christophersmith1894 I'd say so.

@@christophersmith1894 . Indeed. Historical metrics will likely show a net cost (with conventional power) with overcomplicating HVAC. -A simple gas burner in a tin shed probably beats any sealed, insulated, controlled-ventilation McMansion. Comfort -that's subjective -spend what you want on being comfortable. What you describe as "poorly ventilated" is actually poorly sealed yes no cost saving untill the envelope is "controlled"-freely passively ventilated, whenever and wherever the wind blows. Poorly ventilated is an Icebox with the lid on.. have a laugh. It gives me a chuckle too.

I figured it was your boyfriend

This ERV is installed independent of the home's HVAC system. So it does not integrate. Quote from Zehnder "It is essential that the ventilation and HVAC systems are separate and do not share ductwork. This ensures proper airflow rates and energy efficiency". So basically the homeowner will be paying about 2X.

@@sitechca70 How does this not suck all the heated or cooled air out of the rooms and send it outside?

@@skmetal7 That's exactly what the ERV does. Look up how it works. I'm no expert here, merely a residential homeowner who has looked into the benefits of one and decided it wasn't worth it for my house and climate.

@@skmetal7 just look at the whole video, it is explained.

edit kWh - Energy rather than power. NB. This isn't an AC unit - it is additional, for air quality, rather than "comfort".

@@kadmow I know that an ERV system is for air quality. My point is that when you have such an efficient air distribution system such as this Zehnder ERV, you eliminate the need for additional mini split units throughout the home because this system will continually distribute air around the house.

@@JamesBlazen I understand that. Matt has already stated that he will be utilizing mini split heads in his home. My only point was that this Zehnder system offsets the cost of installing mini splits in; say, every room, which I've done. Next time, I would consider the Zehnder option and save the cost of at least half the mini splits. The bonus is getting the fresh, filtered, heat recovered air that the ERV provides. (A requirement anyways on a house that is under 1.0 ACH.)

@@JamesBlazen Energy recovery. That includes heat and A/C

I wonder how long semi-permeable membranes in ERVs will last - in a jacket some break down within 5-10 years. A HRV has more durable partitions - but no vapour permeability

Pretty sure the core needs to be replaced at some point also. Typically you can vacuum them at least, but unsure if that can be done with this one? I expect the core to be expensive to change.

The core should be removed and cleaned every year. Vacuum the edges and run fresh water through it (warning, though, not all ERV cores are water washable like this one). Our filters should be checked like almost all filters on a quarterly basis. Yes, the Luna diffusers provide adjustment to compensate for the varying duct lengths. There can be a couple iterations of adjust registers, but the fact that this Q600 ERV adjusts automatically to maintain the total flow helps make the process a lot easier. Yes, boost is for the entire system (there's no "zoning"). High heat recovery and relatively low airflows are sufficient to avoid cold drafts. Yes, the airflows in each room are usually low enough to move freely around/under a closed door.

Christopher Smith thanks for taking the time to answer.

Any BAS with door switches and motion sensors will accomplish this for you. HVAC controls and window blinds are also common in a BAS. Some DIY guys are using raspberry PI’s to accomplish this rather than expensive tridium/niagra proprietary programming and controllers.

TJ Challstrom Humidity sensor won’t close when you just want to take a shit in the toilet. Make up air would have to be balanced with the same cfm as the fart fan. Wouldn’t want to create negative pressure in the space and pull more air away from the other zones. None of the other duct runs have motorized dampers on them. Constant speed fan at the ERV.

TJ Challstrom all you need is a thermostat with a cap tube connected to the hot water line to control the fan. The water line heats up when hot water is used thus turning on the fan anytime the bath water is used. Low voltage to. Add a 15 minute time cut off delay and it will run 15 minutes after shower is stopped. You’ll never have to worry if someone forgot to turn on the exhaust fan again. It’s simple

Matt answered in another post - no that dirty air ( and, strangely - makeup) - is separate.

Brian Wright If you have electric range like Matt does, it will be not that much of an issue. Most of the bas stuff is coming from the burnt gas. The rest is just smell, which some might even like it. Considering that, the biggest issue will be the moisture, not the air quality.

@@juzoli this study indicates otherwise... www.sciencedirect.com/science/article/abs/pii/S0360132318305183

Brian, I will have a separate system for my kitchen exhaust and make up air. I’m using a Fantech system

Even simpler would be to install a humidity sensor in each bathroom.

Just fresh air/vent. He mentioned he also has a mitsi AC system.

I got 1200CFM Kitchen Vent Hood... have yet to install a MUA yet... Does this system compensate for that or is an extra MUA still required? I also use fireplace in winter... so sometime the smoke is terrible in bad burn. Another headache... However, I do like this system.

Why not hook up to existing fans? You can probably even remove the motor and just leave the grill/shell of it

@@MrTiger0002 - The short answer is No. A 1200 CFM hood should have an exhaust duct of at least 10 inches (12 inches is preferred). That means you'd need a minimum 10" MUA duct. In reality, you'll want the MUA duct to be larger (much larger) to cut down on the inflow air velocity and noise. Both of these base values are larger than the entire EVR system supply capacity. The same would apply to a gas furnace. don't use conditioned air to feed the fire, run an outside supply for the furnace and keep the entire combustion process separated from the living space.

@@valkyriefrost5301 Thank you. Confirms my thoughts.

It's not connected to the Zehnder - only air to the room -

ArthurDentZaphodBeeb but he mentions the exhaust from the laundry room and how its connected.

@@bryce4071 That would be for an exhaust fan in the laundry room not for the clothes dryer itself. The amount of heat, moisture, and lint in the dryer exhaust would overwhelm the system very quickly and would be a disaster. While they did not specifically get into the dryer exhaust, that would have to be run separately to exhaust directly to outside air. The Zehnder system would presumably take care of the makeup air needs when the dryer was in operation.

I’m actually surprised to learn people have exhaust vents in laundry rooms. If its all being taken care of by the dryer exhaust, why? Or is it humidity from the washer maybe?

This would be a heat pump dryer. Smaller and more expensive than a conventional dryer.

the cooler air from the inside cools the air coming in. that causes the humidity to drop out. the humid air from the bathroom goes out

...and these intermittent shower events are just a blip when you're using continuous ventilation and considering the whole volume of the house. Your point is valid in that there is some quantity of humidity staying in the house with moisture recovery, but it's very short-lived in the scheme of things. The continuous exhaust from the bathroom long after the shower is over keeps the bathroom mold-free and that perpetuates good air quality in your house.

If I've got the money to afford it, I'll get as nerdy with my HVAC system as I can. Never forget the nerd factor. If I put one in my house, I'd get endless hours of annoying friends and coworkers about how it works. Worth every penny.

I’d like to think that the comfort factor will justify the cost. Imagine being spoiled by engineered comfort. Downside is noticing anytime you’re in somebody else’s inefficient or unhealthy building.

Running ERV 247 is way excessive.

California already lets solar electricity go to waste during daytime since there isn't enough demand, for example.

Rebasepoiss that will likely not be a problem in the coming years as EV adoption goes up. CA needs to open up the grid so that residential storage can be a supplier, they have so much potential. It’ll likely happen sooner in TX though because of the open grid market (huge advantage)