ERV/HRV vs Dehum - What’s the difference? 

Thanks Matt. Love that you talked about how to use them in conjunction with each other.

Purchased: August 2022 - still works GREAT! ru-vid.comUgkxxsUnXhGsSJLim_XnMHyQK0u3XVaW-CGn I live in a studio and during the summer it gets scorching hot - really old building with no ac units. I can’t express how EASY it was to install.This unit has been a life savior during the summer and some days during other seasons where it can still be a bit warm at night. In this small place is my friend, a husky, poodle mix and myself. We need AC - lolI don’t use the dehumidifier option - I’m not sure if it will leak in my house, since I did not install the small draining hose that came with it. May look into it late but I don’t worry about much humidity in the apartment.I don’t understand why the negative reviews since all things mentioned, I personally did not find issues with. Definitely worth it!

Matt, Would love to see a video that involves retrofitting a system into an existing home with multiple HVAC zones that goes through the considerations and complications of trying to make something fit with existing equipment.

Glad to see this video. Recently put an ultraire dehumidifier in my house because my builder didn’t despite having unvented attic and entire house is spray foamed. I will say in last day or so we noticed we are much comfortable at 73-74 as opposed to having to keep temps at 70 prior to installing the dehumidifier I’ve learned a lot from your videos and helped me make sure my builder wasn’t taking short cuts.

Excellent pros and cons video! You truly serving your viewers with this one! Plus I’m into HVAC 🤓

As a Realtor,love this channel for learning!

Great video Matt. We build in Northwest Arkansas and have all four seasons with times of high humidity. It was not until we spent three years in Arizona that I understood Comfort was not tied to temperature but rather humidity. We would leave our AC at 78° and be more comfortable than 70° in a high humidity area.

This is perfect, as I am trying to decide this very detail.

Watching your videos has convinced me that I'll likely have to build my house to get what I want. One of the big items is the HVAC, I think my personal preference leans towards radiant ceilings and some kind of ducted system to circulate purified outdoor air to keep the IAQ controlled. I have terrible allergies, hate high humidity, and love feeling cold.

Thank you Matt, for sharing how we can reuse conditioned air. On the path to a more regenerative future.

I live in Central Florida. I just had the insulation 2.0 system and the UltraAire 98. Dropped my bill by 1/2. We work from home and were very worried about indoor air quality. Glad I watch you and this old house.

Thank you so much for going over this. I literally ran into a house today that the engineer advised putting ERVs in. The house already had humidity problems (it’s over 70%) and this is in Tropical climate (Miami area). I told the client exactly what you’re saying.

Matt, we recommend installing the ERV/HRV and taking the bathroom air back to the unit with a UV light in the airstream before the coil. Some people in the area like to add the dehumidifier also, however that is on higher-end homes where more space for mechanical is available. In mid-range to low-cost housing, we generally use the A/C system as the dehumidifier like in a car as the retrofit in the controls package, changing the humidity levels based on air-changes and base temperatures. This can work for home and commercial systems.

Very interesting and very informative ... great job explaining what I consider difficult thermodynamic concepts. 👍

How do you install both systems? Are they on a separate duct system together? Would like you to do a video on how these are both installed

Great explanation, Matt. Thanks for the video! You couldn't have been any closer to the truth when you said that every home down here in the south needs a dehumidifier. When I purchased mine, it was literally my best investment ever.

Great video. Anyway you could do a comparison between brands of dehumidifiers such as Ultra air, ideal air, quest, anden etc.

Great explanation, thanks Matt!

I'm in the design phase for a new, tightly sealed house in Atlanta, GA (hot, humid climate). We plan to use the same combination of ERV and whole house dehumidifier that you discuss. My question is about ducting. I would guess the gold standard method would be to duct both systems independently. But how well would it work to use a dedicated return line for the dehumidifier but then duct the supply into the ERV supply line (somewhere after the ERV unit). I know there might be static pressure problems if both units run at the same time, but could you set it up so the dehumidifier turning on turned off the ERV? Would you be able to run the dehumidifier long enough to deal with the humid Atlanta air while still allowing the ERV to run enough per hour to bring in sufficient fresh air? Thanks Matt! Great topic!

Seen this on This Old House the other day. Now on the dehumidifier, creating dew...in a dark, cool place.... sounds like another great place for mold to grow.

Hi Matt, very interesting comparison! We just finish to build our home here in Europe, Mediterranean aerea, not so cold but quite warm and humid in summer. We installed a combi machine that does HRV + heating through the ventilation and onboard heat pump + domestic Hot Water. To solve the problem of the air humidity and A/C functionality we installed an indoor coil connected to another external airconditioning heat pump. This indoor coil is installed just before the supply collector and works independetly from the combi machine. What do you think about the combi machines in general for the modern high energy efficency homes?

Many homes have just too much air leakage. All new homes and all remodels need to have a blower door test and seal up air leaks first. I wish all builders / remodelers did blower door tests as standard practice. It makes the home more comfortable and saves energy / utility bills on heating and cooling.

Matt, I have about 62% humidity in the winter in the house after many HVAC/insulation upgrades (Central Connecticut) I have ductless mini splits but rely on them for heating in the winter I’m gonna put in a Panasonic Select exhaust fan running 24hrs @about 40cfm in the bathroom (centrally located) hopefully that will fix some humidity issues.. from there if I continue to have issues I will have to install a stand alone dehumidifier like one in your video here.. THANKS!!! Great VIDEOS!!!

Happy new year Matt, the best for you and family this year. I agree with you in some of the stuff but the need for dehumidifier on a tight building depend on occupants activities and having a dehumidifier it is essential. I will never use that unit as a fresh air intake, that it the task for the ERV. By the way what happens to your hair ?

love the videos. I have posted before but I would love full length "how to" videos in conjunction with the great explanation videos you do. Is there a cheaper way to control the ultra aire dehumidifier than their $250 Ultra-Aire DEH 3000. Seems expensive when adding to the cost of the unit. Thanks

Northwest Arkansas- I’ve seen humidity in the single digits when it gets cold for awhile in the winter. During the summer that’s a different story. Not uncommon for humidity outside to be over 90%. In this case I like the idea of a dehumidifier

We just built a house and did a handful ourselves including the air sealing. I put so much detail to not miss anything and got our 3600sg’+ ranch with 10’ ceilings in main and an unfinished basement. Got the house to 1.30 ACH. We live in Nebraska so we can see everything from cold and dry and dry to high and humid. I am stuck on what to do. We also have Geothermal, with gas auxiliary heat. My goal with building was to not ever use the auxiliary heat except for if we lost power.

Matt, I see Ultra-Aire offers ventilating dehumidifiers (I'm looking at the XT155H). Would there be any reason to use an ERV if you configured the XT155H to provide ventilation?

Loved episode. Currently framing and in mid west. Planning hard wood floors and a humidifier. Planning ERV for fresh air, but wonder if a dehumidifier in addition also be a wise choice? 2800sqft

👌 perfect topic. Thanks I was just trying to decide what’s the best approach for my cottage, that has a 3 seasons building permit, but is used regularly in the winter as well. We have hydronic in-floor heating in 3” slab floors throughout, so the heating system doesn’t dry the place out at all in the winter. Window condensation is an annoying issue, especially with wooden interior window frames, along with drywall returns 🙄. I had an HRV pretty much from the outset, but it doesn’t seem to do that great a job once the humidity level starts getting down around 40%. Recently, I purchased a whole-home dehumidifier, and it also doesn’t seem to take that much water out of the air at the lower humidity levels either…

Matt, as a mechanical engineer, I only want one item in a very tight home bringing air into the house. Therefore I spec an ERV for that. I also recommend dehumidifiers for the interior of the home that are fixed in the home and drain to the plumbing system, but do not connect the air stream to the exterior. Also, I pull air from all bathrooms, kitchen, and peak of vaulted ceilings and exhaust them through the ERV. I put the fresh air into the large common areas where no one will sit, since that air may be a bit cooler or warmer than the air in the house. This strategy has worked well in design and works well in my own home. I do engineering in the southeast US.

Very informative, specially if your in a humid climate. The drier states were not addressed though. There are many states that don't have the humidity issues you were talking about. I.E. Idaho, Nevada, Arizona, New Mexico, Wyoming, Montana, Eastern Washington and Oregon And 3/4 of California, basically states west of the Rockies. The ERV seems like the unit of choice, would like a more detailed evaluation on that.

I've been waiting for this info for years ..thanx

Love the dry heat.

I have installed hundreds of what we call a mechanical ventilation heat recovery unit (MVHR) here in the uk. In flats mostly and about to do houses. I have retro fitted two into my own properties and saved a load of money on Heating bills. They pay for themselves in a little over a year. They also have a condensate Drain and humidity sensors. Great bits of kit. I installed a vent axia unit in a flat and a Nuaire one in a barn conversion.

thanks for the educational video. Cheers from Maui!

Dear Matt, Thank you for your video. Is it possible to use ERV in tropical climate such as South East Asia area. if we use ERV for our home, do we need to have a separated exhaust fan for our bathroom/toilet? Hope you can help

Great timing as usual! I’m looking at putting in 2 ERV’s and was thinking about a dehumidifier (for the summers) and humidifier for the super-dry winter days (here in Pacific Northwest). Here’s the question: We’re also installing a 60” range with a hood/vent in the kitchen and we’re needing a makeup air system in the kitchen. We’re thinking about having the MU air come out from under cabinetry across from the hood to create a type of air curtain. How do (or would) we tie that cooking makeup air system in with our ERV’s and (de)humidifiers? Thanks and I look forward to seeing ya at IBS in a few weeks!

Another great build Matt!!! Should Central Texas new Homes also have a humidifier such as the Aprilair 800?

What type of energy load do these units put out? I'm looking at being 'off grid' and need to take this into serious consideration. I live in Oregon, the PNW ... Pacific North We(s)t. I've been watching a plethora of your videos and am already looking at ICF, Zip R sheathing, amongst others. I would like to keep the humidity down as well as my energy expenditure. Hopefully soon all of these components will come to fruition with my own build. Thank you for sharing the wealth of information!

We'd love to see you cover the CERV2 for intelligent IAQ.

Matt, if running both, an ERV and Dehumidifier, how would you duct them? Would you keep them complete separate or join them together, does the ERV feed the Dehumidifier or vice versa?

Matt, how many minutes per hour (or equivalently, what percentage of the time, or cumulative hours per day) does your Ultra-Aire 120H dehumidifier run during the spring and fall seasons in your new 2800 sq.ft. house there in Austin? Btw, love your channel and vids, learning a lot from them in planning the build of my future zero-energy solar home. I’m trying to understand what the energy consumption of these ERVs and dehumidifiers is. In another video, you said that your new Zehnder ComfoAir Q600 ERV consumes around 100-125 Watts continuously, 24x7. So that’s around 2.4 to 3 kWh per day. Here in this video, you said that the Ultra-Aire dehumidifiers consume between 5 and 8 Amps when they’re running (so that’s 600 to 960 Watts), but you didn’t say what percentage of the time they typically run (e.g., in your case, specifically, during the spring and fall seasons there in Austin, when they would be most needed and heavily used). Hence my question above. If your Ultra-Aire 120H dehumidifier runs 50% of the time (30 minutes per hour, or 12 hours cumulatively per day), that’s 7.2 to 11.5 kWh per day. If it runs a third of the time (20 minutes per hour, or 8 hours cumulatively per day), that’s 4.8 to 7.7 kWh per day. Even running only a third of the time, that’s still a heck of a lot of energy consumption for a solar-powered home trying to achieve zero net energy. Thoughts or comment? Thanks!

Matt, do you happen to know what production home builders install to satisfy whole house mechanical ventilation requirements required by IRC?

Thank you for sharing. Can you specify both maker and model? Also, how about space pressure diferential?

Thanks for the video, Here in Sweden the outdoor air quality is good enough that filtering the air isn't really needed. So I stumpled upon decentralized ventilation with ceramic stones that claim to recover 90% of the heat and 20% of humidity. The idea is so clever. It wouldn't be my first choice since you can probably hear the fans in each room. But I would love to see a video about this. Unfortunately it's not really an option where you need to cool and/or filter the incoming air, I suppose.

I know it is sponsored but I love this type of episode

I feel like in northern climates an air exchange would be great. 90°F+ during the day and sometimes only 40s over night you could cycle out the warm stale air in the house and bring in the cool fresh air through the evening

Thank Matt 💞

This is an older video, but we are currently choking on wildfire smoke in California. This seems to be an annual thing for us. Would love to see how to design for, then use, modern home HVAC systems when outside air is horrible. Thanks!

I live in a country where relative humidity ranges from 51% to 97% and the temperature ranges from 24 degrees Celsius (75 F) to 35 degrees Celsius (95 F). May I use an ERV but invert the intake and exhaust?

Matt which of those systems would you recommend for Southern California?

The prerequisite before using the product is that no outside air enters the room. Air gaps in windows and front doors can change the efficiency of the product.

Wow, interesting to see an objective perspective to these devices. I live in Europe, Germany and it`s horrible here. By law, all new houses have to be built with HRV, even if you dont need it. We dont have something like a ERV here. Additionally if you dont live at the coast, you will have at least 2-3 months of summer with +35°C degrees and huminidity sometimes is high, with 60-70%. And you just dont have devices to cool the air and get the humidity out. You are not allowed to built your home with A/C, if you do, you will get problems. And to be honest, I dont know if a dehumidifier would be allowed, but I have never seen a home which has one and have not even heard of that possibility here. Next problem here is, the HRVs are built that way, that you cannot turn them off. So it has to run 24/7, 365 days of the year. As a result in summer, you get the hot air blown into your house. And you are not able to get it out. Of course you can open your windows at night, but nights sometimes have 23-24°C, its typical windless in summers here (if you dont live at the coast) , and if your house has 29/30, it may cool down at 25/26 during the night, but it`s impossible to make it any cooler than that. And it won`t last long, because the HRV will start blowing hot air into your house as soon as the sun heats up the air. And of course, additionally you are not able to get humidity out too. I really hate politics here. It`s just a green bubble without any logical thinking and arguments. Because in case you dont live in the mountains, the winters don`t even get that cold. There are regions where it has not snown in the last 5 years. And many may have snow, but only on 5-10 days of the year. The majority of the other winter days will have something between 5-10°C. But they argue because of heat loss in the maybe 30 winter days, where you heat a bit more, you must install HRV. And as a result you have at least 60-90 horrible hot days in the summer just because you have to install HRV, which has to run every day, cant be turned off and you are not allowed to use A/C (and dehumidifier probably too). It just sucks to live here.

I have the 2nd model VanEE HRV that was ever made in our house we bought this fall. It seems to be working just fine but when should we think about replacing it? Would it be worth it for us to get a new one and a dehumidifier to go along with it?

Great video Matt. I have a new home 2600 square foot, in Louisiana, and its just my wife and I. What do you suggest for setting the Ultraaire for venting and fan

I really like your videos. I always seem to miss out a bit because i'm in a different climate than you. Northern Oregon. Im buying a 1940's home and making a list of all the things i want to change in it. Looks like an ERV is going on the list alongside a new furnace.

Can you explain better HOW these work together? Do you disable the motor in one of them so the motors aren’t fighting each other? In what sequence do you connect the ultra aire and erv? Indoor air, to dehumidifier, to erv Indoor air, to erv, to dehumidifier Or some other sequence?

I'm now renovating my 1952 log frame townhouse. I live in Finland where it's mostly cold and heating is required about 7-8 months a year. I bought a air to air heatpump from hitachi to cool down my house in summer and it has dehumidifying feature build in. So I'm actually going to heat my house with air to water heatpump with floorheating. Also water preheating is done with that same heatpump. I'm hoping to lower my energy useage (moneywise) to about half of what it was before. The house had oil heating with about 3000liters annual consumption. hoping to get around 1500€ with electricity bills

really enjoy your channel Matt. Curious about how you are piping these systems. are they each running independently? I'm hoping to build in 12-18 months and want to do a passive[ish] house in a hot humid climate. very interested in doing radiant chilled concrete floors + ERV + dehumid. I'd also really love to see a video on wall and roof penetrations. I'm very curious about how you go about keeping these tight, air sealed, and waterproof

Matt can you do a review of Tesla glass roof titles please. You would be one of this first to review this product, very innovative !

Great Video! thanks!

HEMPCRETE! please do a video about hempcrete! I value your opinion and I want to hear what you think about it. Thanks for your content

Matt, I have watched many of your helpful videos over the years & really appreciate how you helped me design & build my energy efficient retirement house that includes a HRV. Your use of the word mixing is off the mark, you could use exchanging. Then 2x times you said that the dehumidifier brings in fresh air.

Hello Matt. I live in Round Rock, next to Austin, and I'm looking for a good contractor to install an ultra-aire ventilating dehumidifier in my existing house. What contractor or HVAC company would you recommend?

Matt, would a santa fe ultra 125 with fresh air intake b better? Could you run the dehumidifier into hrv or erv then to home?

I got a manual j performed and they said to use a 2.5 ton heat pump for my house. However I already have a 3.5 ton heat pump that has spray foam on the attic and blown insulation on the walls. Is it ok to leave the 3.5 ton and get a whole house dehumidifier? Thanks

Its great that code requires fresh air coming into houses - I live in Eastern Europe and apartments here are just built as completely sealed boxes. I need to keep my balcony door constantly ajar to let in fresh air. Alternatively some apartment blocks have poorly designed communal ventilation system, which just distributes noise and cigarette smoke into other apartments!

In radon areas wouldn't a bit of positive pressure from the roof be a good idea?

If you lived in an underground concrete bunker where you need to control the humidity inside more than anything else, how would you insulate and control your air quality inside? Would you use an erv and a dehumidifier? Does the dehumidifier only dehumidifier the outside air?

I feel like "dry" is a relative thing. I lived in a house that got so dry my lips would just start cracking. It's really 45-50% thats comfortable. The probably is humidity is really a problem as temperature changes which is why really forced air systems should have dehumidifiers on them. Whereas on a high performance house with plenty of insulation and slowly changing temps managing the humidity is doable in other ways including just venting with an ERV. I question the idea that simply high humidity outside would cause an HRV to go airy at least as a general rule. Even if you lived in a coastal area where you can get up to 65% humidity only a fraction of that gets through the ERV. The problem therefor is that the HVAC is actually just not providing any dehumidification in a lot of circumstances and thats a design problem with the HVAC. if the HVAC is suppose to be a high velocity system that only runs for 30-40 mins a day now you have another problem with an uncomfortable forced air system that blasts hot or cold air at you and no dehumidification.

Hello from Russia. I impressed, that you compare this type of recuperator and dehum. There are different types of recuperator: aluminium or special plastic. These types of recuperator more effective! In Europe we successful used them for swimming pools.

Nice video, Matt. Thank you! Question from the higher altitudes. My wife prefers the house sit at 45-50% humidity, but the outside air is 10-15%. Is there such a thing as a central humidifier? I’ve never heard you mention one. And I don’t want every bedroom to have a humidifier.

I have (2) 70 pint store bought dehumidifiers. They are pulling 250+ pints most days from my 2k sq home. They both are running now and it's 62% humidity in here. It would be in the 80's if they weren't running. I have a pool that gets ground water behind the liner. I'm being told due from the lake the property is on. Im guessing those issues are contributing to the humidity in the house?? Does it sound like I have more issues than what a whole house dehumidifier can fix??

I may need all 3. But need hrv on my "vent to daylight" and erv because large planter in passive solar cottage. And may need to pull more moisture out of the air. And with the timber frame and masonry north wall and floor. I want the wood to dry properly over time. Plus will have masonry stove/white oven and heater. Which will need to make pit for hrv near intakes for masonry appliances. Slope floor slightly to allow cold air move that way too. On border of I.E.C.C. zone 6/7 great lakes.

Do you need Dehumidifier and ERV in Connecticut or only ERV? Thank you!

Matt, you and none of the comments below mention all of the dehumidification water being pumped outside the hose, next to the foundation. In Atlanta our small system of 1,400 sf pumps out 3-5 gallons a day. I drain it into a 55 gallon barrel and regularly lug 5 gallon pails of water to my dry garden areas. I'd like to here what you and others do with this flow. Maybe most just run the water line to a drain.

Question about installing these units. I agree in the warm-humid areas (I am in North Carolina) we need both units in a house. I have ductless minisplit heat pumps (7 IDUs, 2 ODUs) and 2 ERVs in my new house, but the humidity gets too high. However, I have been racking my brain trying to figure out how to integrate the two. My ERVs have dedicated ductwork, which I want to use for the dehumidifier I need to add. I guess I will need to add 4 new electronic dampers to plumb into the existing ductwork? But then, how do I deal with the controls? My ERV controls read humidity. If the ERV is on a 20 minute per hour cycle, can I wire the dehumidifier into the ERV outputs to open the dampers and power on the dehumidifier for the other 40 minutes? Also, why are all the whole house dehumidifiers 8" connections? Most ERVs seem to be 6"?

Should I run the ERV 24/7 in northern Canada during winter time??

1966 Bungalow 1200 sq ft 2x4 Construction + ext rigid foam ACH of 1.9 Double pane windows No HRV or ERV Heated with 18,000 BTU LG Ductless Split Family of four Condensation issues on the windows attempting to be rectified with an Energy Star stand alone dehumidifier in the basement. Even with humidity

So this would be in addition to a whole house AC systems ? I am planning a house build in a year or 2. I live in upstate NY near the Canadian border. As you can imagine, a good portion of our time is in the heating system when the air gets pretty dry and people tend to use humidifiers. But then, we do get a few months in the summer when it can get warm and humid (probably not compared to Texas & Florida standards) and many people will use window AC units. I would prefer a central AC system in the new build. Just trying to do my homework to address both extremes we experience up here.

Hi Matt, Love the channel!......just a suggestion...replace the word “suck” with “draw” 🤠. Thanks for explaining air exchange/dehum. We will be installing in our next house.

Overall a pretty good video. Some really good information if homeowners are looking. You just are incorrect when you start talking about the refrigerant cycle. Outdoor units do not make refrigerant cold. Also you should use the term refrigerant and not Freon. Being you’re talking about D humidification obviously the unit would be running in the air condition mode. The line that you feel that is cooler is actually coming back from the indoor unit. Technically you cannot make cold you can only remove heat. The sub cooled liquid refrigerant hits the metering device at the indoor unit causing it to flash off and change state to a vapor. After leaving the metering device it’s now 80% vapor 20% liquid. The air moving across the indoor coil causes the rest of the refrigerant to flash off and now becomes a superheated vapor by absorbing heat from the air. The cool line that you are feeling by hand coming back to the outdoor unit technically is what is holding the heat from inside your house.

I though -- perhaps incorrectly - that Austin was relatively dry. 40 - 60 RH actually sounds sort-of high to me. When I think of art museums I think 45 RH. In the northeast, if you step into a museum during heating season you can really feel the increased humidity. In the northeast, your AC does a good job of dehumidifying except in homes like mine where occupants are constantly opening and closing doors to let dogs in and out or leaving bedroom windows cracked at night. During the heating season we are left craving a bit more humidity.

Matt, Why would the close the dehum incoming air instead of running all of the ERV thru it? Is there any advantage to keeping these units seperate?

Hey I have a question? I have a 200 square foot tiny house with closed foam insulation and because I also use it as a greenhouse in the winter time and of course because of transpiration of the plants and evaporation of the soil after a watering… on top of two adult people breathing, I am getting a lot of humidity in the winter time. I also live in the SW Virginia area so we have pretty humid summers here too. Which system would work best for this application and HRV or ERV? I know both clean the air Im just more concerned with excessive humidity. I see a lot of people in tiny houses using HRV but what do you think I should do. Also I am looking for a very small unit… any ideas there, because its again only 200 sq ft?

If you want to install an ERV into an existing house, and you don’t want the furnace blower to run all the time, what can you do? Can you take the stale air from the furnace return ducting, and then cut a hole in the floor to add a new vent or 2 for the fresh air to get back into the house? I have a single story rancher with an unfinished basement.

These unit are adequate for low CFM exhausts as in a bathroom BUT a gas range needs a exhaust hood using 400-900 CFM (or more) by code . You will need to have a independent air replacement ducting in place with a active air flap to replace that much air. IF THIS air comes into the home very close to the range the Hood will actually work . (no high volume air replacement results in Minimal air movement in hood exhaust and code violation.)

Would an ERV and dehumidifier be necessary for a new build, 1850sf.

I'd like to see how effective the thermal bridge is. How much does the temp of the incoming air change; 5°, 10°, 20°?

Man, I am living in Minnesota and we hit 80% humidity in the house from spring until early fall. 90 degrees in the summer too. Its as bad as Houston (son of Texas here). We are looking to downsize our home, I think I want to do something like this in whatever we buy.

Hi, could you help me solve this question? If my home rh is 70% at 18, outsidw is 40% at same temprature. What will the in door humidity be after several day use? Thx

Matt, anyway to see your installation on these bad boys?

I’m in the north n in winter window moisture is an issue. Anything from dew to frost on window panes. Definitely have more with higher humidity n less as it goes down but none the less it’s there. How about some feedback on this.

I have an hrv and in the winter it actually makes my too dry in the at only 20% humidity. I need a separate humidifier most likely?

Do they make small ERVs for tiny houses? That unit is way too big for my tiny.

Thanks

Oh the ERV model looks like the 90's air exhange units nordics have used with this "box shaped" crossflow heat exchanger where air streams are only roughly 50% efficiently transferring the heat. Modern units have long counterflow air exchangers to get the efficiency up to 80-90%. My 20 year old unit is basically just what there is on the left and it was the cheapest option to satisfy fresh air requirements (here it is 1/2 of the house volume every hour) but the energy efficiency is.. well not the best. But yes it has balanced airflows and it recovers some heat / (cool during summer) to fresh air but only roughly the half as the box shaped heat exchanger is .. well cheap.

Building a 3000 sq ft pole barn in Taylor. Was going to just drop in an ERV, but now you are saying it might be better to have both. And with the second unit, close off the fresh air as the ERV is bringing it in? Is there a way you can show a drawing or something on what exactly you are referring? I was going to use the ERV to pull the moisture from both bathrooms and the kitchen only and bring fresh air into the theater, living, and both bedrooms. Any input is great Matt.

I dont know much about the difference between hrv and erv, but Matt emphasizes that dryness in a house keeps fungal growth down and generally keeps your house from rotting and mold. While this seems to be true, is it not also true that ADDING moisture to your home's air helps to keep a home warm? I heard somewhere that in cold climates like Canada, where I happen to live, adding moisture allows the heat to be more effectively distributed around the house compared to a dry house. Thus, your furnace doesn't run as long to keep the house at the same temperature as a dry house. Is this correct?