Hi all! I’d like to mention that even if you live in the desert, you may still need a dehumidifier to supplement your ERV! Even arid regions can get humid during certain times of year.
Outstanding content - thanks! One idea you may not have explored: In the event that you are building a new house or doing a deep remodel, you can elect to use clay plaster (not lime plaster or drywall). Clay-based plaster is an ancient technique that has been used to passively control humidity for thousands of years. It was recently revived by Geoff Lawton in the Greening the Desert project in the Dead Sea. By replacing 80% of the lime in plaster with Bentonite clay, the walls act as a hydric buffer (not my terms, honestly it's the engineers who name these things). When the air is damp, the highly hydrophilic clay particles in the wall absorb moisture like a sponge. When it is dry, the walls dry, releasing moisture into the surrounding air. Result: the indoor humidity settles in at around 45% to 55% regardless of the humidity outside or inside the home. This technique is used in Japan (a very humid temperate rain forest) where the problem is atmospheric humidity, and at the Greening the Desert project in Jordan, with an annual average humidity of less than 20%. This technique produces a lovely wall (decorators call it "Venetian plaster" it's quite on-trend at the moment). The largest challenge is finding plasterers. Plaster on lath is cheaper than drywall (materials cost) but more expensive labor costs (it takes longer and you need a higher level of skill). But, it's still only about 10% to 20% more than level 4 drywall, and you don't have to buy or power expensive mechanical humidity control equipment. To my mind, the set-it-and-forget-it nature of a passive self-regulating system that never needs maintenance or power, makes it worth the extra up-front cost. I would love to hear your take on this technology, as well as other recent tech revivals such as GAHT (ground to air heat transfer) systems, rocket stove wood heating, and Russian masonry wood fired heaters.
Thanks very much Linda! Clay plaster does sound very intriguing - I love the idea of not relying on mechanical devices for humidity control. I'll put clay plaster on my list of topics to dig into. My only concern, which may be unfounded, is about silicosis, a long-term lung disease caused by inhaling crystalline silica dust found in clay. That could totally be a non-issue here, but I'm curious. Anyway, thanks again for your interesting comment!
@@GeraldLeenerts I looked into wool insulation, but it is SO much more expensive than cellulose. I'm building in the Arizona desert (high in the mountains, away from the baking heat of Phoenix). I will use double-wall construction, with adobe on the outside, a 2.5" gap, and a clay plaster interior wall on 2x4 framing. So the final wall will be 16" thick. I seriously considered blown-in rock wool, real sheep wool, and cellulose. Cellulose wins hands down as the low-cost option. It doesn't have nearly the humidity buffering capacity of wool {sigh}, hence my desiccant built into the walls design.
@@HealthyHomeGuide 😯 That hadn't occurred to me. Wet clay isn't the problem, it's the clay dust that's the problem. 🤔 Since this is a single installation I will be sure to insist on good masks for everyone involved with mixing the clay into plaster. Thanks for the heads up! I can't wait to see your research.
@@lindacgrace2973 Glad to hear you went with cellulose, as it is a carbon negative product compared to rock wool. I've built a passive addition and working on remodeling our house to be passive as well here in Phoenix. So completely different climate but there is some overlap. There is a pretty good group of folks here if you ever need to bounce ideas around.
You can make an ERV by using plates that are air barriers but vapour permeable, rather than plastic. Materials like Ametalin vapour permeable wall wrap might work for DIY
You are an honestand and admirable to admit you learned and needed to course correct. Kudos to you! I am curious if your horizontal orientation prevented any partial condensation and drain off as all the commercial ERV/HRVs seem to orient the core vertically such that gravity can drain any condensation in channels as the dew point is hit.
That's very kind! I feel that I owe my viewers my full honesty and authenticity. Good question. I do believe that the horizontal orientation played a role in condensation pooling a bit. However, the level of condensation never got out of hand, and funnily enough, I couldn't see much (if any) mold growth inside the HRV, probably because I kept it constantly running, so constant airflow. If I had used an air conditioner in the room the HRV was in, I probably would have seen worse condensation. Interestingly, after removing the HRV, I actually tested some simpler fresh air intake systems, and they also introduced too much moisture into my house. So I don't think it was the HRV itself per se causing the mold issues, more just the practice of ventilating without controlling water vapor.
100% agree with you. I don’t understand why the industry advises the opposite in all their specifications. I just finished a new house and installed 2 ERV’s with resistance from the HVAC supplier. Fortunately I have taken classes in physchrometry over 20 years ago and that knowledge is still paying off.
I salute you! I feel that psychrometrics is the #1 subject that everyone interested in creating a healthy home should understand. It is such a huge problem that the HVAC industry is largely unaware of the dangers of using HRVs (especially without dehumidification) in humid regions. The HVAC industry also unfortunately heavily favors people with ducted systems in their homes. I hope to solve these problems someday.
Ouch! Yeah, living in the uk we know all about damp air :( . Lots of older houses that have been 'half fixed' ie made 'warmer' by using double glazing and sealing drafts appear to be suffering with damp issues.. We certainly are. So HRV is definitely not a solution!
Thank you for the video! Can I make a suggestion? Explain things in plain language first and then note "that's called latent energy recovery". Otherwise we have to try to remember the labels while you fill in the details.
I want to avoid dry mucus membranes/sinus etc during winter - huge problem for me. Is what you are saying this?: INSTEAD of having a bit colder temp 18C AND use humidifier to get up to 45% RH ---> JUST increase temperature to 21C (And humidity will come along anyway)
Thanks for the question. No, that's not what I'm saying. I recommend that you watch my video on humidification titled "How Healthy is Humidifying REALLY?" It should answer your question.
Good follow up video. My house is good for humidity, but my chicken coop is too humid and I'm working on solutions to that now. Dehumidifiers are a tricky bet there because of all the chicken dustiness.
A MERV-13 filtered dehumidifier such as a Santa Fe Compact70 could likely handle the chicken dust no problem! Though you might have to clean the pre-filter somewhat often. Have you considered this?
Definitely pre-filter + filter. There must be a reason commercial solutions use more than one filter in series. Big particles don't clog the fine filters too soon. Also, you can usually wash a coarse filter once. And can buy coarse filter material "blankets" and just cut to size
I'm in the early stages of addressing the issue, so I haven't delved too deeply into any options. The humidity issue is of my own making. I decided to re-route my radon vent into the chicken coop to keep them a bit warmer in the winter and cooler in the summer. The air blowing out is always about 55 degrees F. But it's also very humid. I knew this going into it and figured I could try to address the humidity issue once it was set up. A total solution for it is to simply run the air through a radiator in the coop and then vent it out (only having transferred some of its heat, but not the humid air itself). I may go that route. I'm on a fixed budget for electricity usage because I'm running on a solar voltaic system. So trying to figure out what approaches can work with the least electrical burden. Thanks again for this video! @@HealthyHomeGuide
Wow, that sounds fascinating to run the air through a radiator and vent it out (only having transferred some of its heat, but not the humid air itself). I agree that a dehumidifier wouldn't address the underlying issue. I like your thinking and I wish you luck. @@PraxisPrepper
I'm fairly fond of your thinking style too - which is why I keep checking out your videos. I didn't even know ERVs were a thing until your video.@@HealthyHomeGuide
This is a smart question. If we're assuming that both the window fan and the HRV are producing the same airflow, then yes, they would introduce the same amount of moisture. After removing the HRV, I actually tested some simpler fresh air intake systems, and they also introduced too much moisture into my house. Anyway, positioning window fans so that they actually produce decent airflow is actually an art! Check out this video to learn more about it: ruclips.net/video/1L2ef1CP-yw/видео.htmlsi=8igAC-mCHH1mReqw
Thanks. Given he was using a shot glass to illustrate the quantities I wondered if he was being cute & talking about whiskey. Then I realised... Imperial units... so bad their theme tune is used for the Emperor in Star Wars ;-)
Do you know of any ERVs that are sized for a single room? I'm planning on using a mini split heat pump as cooling source, but I suspect that with a well insulated room it won't operate enough to dehumidify the room.
To my understanding, the ERVs are a similar concept as the HRV, but they use a rotating wheel with desiccant in it. The desiccant absorbs the humidity from the humid side, and the wheel rotates it to the dry side where it dries the desiccant and puts the humidity into the air. Very simple.
Hey. Although making ERV out of cheap HRV won't be easy, I don't think it would be unfeasable or too cost inefficient. With the design you made, well firstly you'd need actual countercurrent in the heat exchange unit - your design goes in 90° fashion, which also lowers efficiency. Once you have this solved, you'd only need water transport material - wick (could be any textile) that would transport water from one end to the other. Simples thing I can think of would be either textile or steel mesh added on the side wrapping around the inlet-outlet and on throughout the length of the exhanger. That material would need strong capillary action, so microfibre "quick drying" towel would probably be the best. Both would pickup the condensation and transfer it to the other side, where it would evaporate to dried out air - this would work both ways. If done properly, this wouldn't affect efficiency, but you'd get moisture transfer. The proper countercurrent construction would likely increase the efficiency anyway already. Other, more advanced improvement I can think of, is making 3 countercurrent exhange units inline, with inside/outside separated in chambers between them, with 2 or 3 wicks running between inside/chamber/chamber/outdside in either alternating or linear fashon, so that moisture exchange would also be gradual, but I think it would not do very much, since the moisture transfer would only occur at dew point.
Moisture control is an interesting topic. In a tightly sealed construction like a passivhaus (or similarly built), I hear that even with an ERV it's not enough to regulate moisture. That's often because the minisplits that are typically used to condition and heat such buildings can't remove enough moisture as they are sized correctly for the passivhaus type cooling load, but that sizing will make them undersized for the moisture removal requirements. So they can't deal with it by themselves, and one does wind up needing a dehumidifier for the humid climates. But the resulting advantage is that (with some effort) the end result is a house microclimate that can be quite precisely controlled.
he got paid to encourage you to buy that crap. Folks...just ventilate your homes by opening doors and windows when is cold in the morning (during summer) and warm in the afternoon (during winter) and then use your air conditioner/furnace few extra minutes to compensate for lost energy inside your home and....that is it. An outside thermometer showing relative humidity will help and its just around $10. ERV installation cost is $3 - 6 grand, dehumidifier install cost for whole house is can range $2.5 - 3.5 grand. You will never recover cost of those devices and you will pay more for electricity. ITS JUST NOT WORTH IT....but it's just my opinion. HVAC industry come up with worthless gadgets all the time and they try to make money on it. Some of their product are good but rest of it is just pure...and expensive junk.
No, I was not paid to tell you to buy the items in this video. If my content is sponsored, I will always clearly disclose that. None of my content is sponsored yet. I make these video because I've suffered from environmental illness, and I want to help ensure that what happened to me doesn't happen to others. I've tried your ventilation strategy and it did not work for me - I live in the northeast US. Opening windows is often not a healthy or reliable option for diluting the air in one's home. For one, outdoor-generated particle counts are often surprisingly high. Get a particle counter and test it for yourself. Though it does help to dilute the concentration of VOCs and CO2, opening windows often RAISES the overall particle count. Also, there often isn't enough natural airflow through windows - it's inconsistent. Also, what if it's too humid outside? Too dry? Too hot? Too cold? Using an energy recovery ventilator is far superior to opening a window. I have videos where I demonstrate DIY installs of both an ERV and a dehumidifier. It doesn't have to be as expensive as you say, though it usually is for a professional install. For those on a tighter budget, I also have a video where I show how to build a DIY fresh air system for a fraction of the cost of an ERV, but of course, without the energy recovery benefits.
I live in a similar clime to you, I haven't constructed it yet, I intend on using your DIY HRV design. Learning from your mold disaster, I am going to see if I can incorporate some form of charcoal, or likewise inexpensive filter inserts for probably at intake/exhaust from the outside.. I feel like it would help, but also decrease volume. Just my idea, and 2 cents.
The mold issue primarily occurred in my home itself. This was from the humid air the HRV was bringing into the house. Some amount of mold is everywhere, and whether or not you filter the HRV (which I did), mold will grow quite a bit in humid conditions.
I was finally able to install and run my Broan ERV on Friday, waiting for a break in the rain to install the inlet and outlet through the side of the attic. Since my heat pump's air handler uses 500 watts to run I gave the ERV a simple dedicated duct system, pulling stale air from the two upstairs bathrooms and sending fresh into the hallway between the three bedrooms and near the upstairs HVAC air return so when the heat pump is on it will help circulate fresh air through the house. To keep from having to constantly change tiny filters I installed a larger insulated in-line filter to the fresh air supply coming to the ERV. ~100cfm only takes 44 watts per hour. It was so nice watching bedroom CO2 drop from 1600 to the 700s. I installed a Tamarack Perfect Balance air return in the bottom of one bedroom door so far and will be doing the rest soon to help keep air moving through the house even when doors are closed. Thanks for sharing your setup and helping me feel like setting up an ERV would be worthwhile even without having ductwork go to every bedroom.
Fascinating! Thank you for sharing your electricity usage and for the tip of installing a larger in-line filter. That little MERV-13 filter inside the Broan ERV is annoying to change for sure. Your configuration is super cool. Email me if you’d like to be featured at some point.
I'd say a mixture of the old rotating ERV should be possible with your same design or similar. But yea the new ERV are using membranes that actually let about 50% of the moisture pass through the material.. so that type of material isn't feasible for regular people to get. At least no long term lasting stuff. You could build one out of cotton I guess, but it'd have to have much lower air flow and be much bigger unit lol
I work in the building HVAC arena (P.E.), specializing in energy reduction and comfort improvement for K-12. Yes, everyone should know more about psychrometrics - but it will never happen.
That's very cool, welcome! You're probably right. All we can do is keep spreading the psychrometric gospel. I do think cheap little hygrometers that display the dew point would also be helpful.
I'm enjoying digging through your videos as I recently purchased an Aranet4 CO2 monitor and realized my bedroom CO2 levels can approach 2000 so now I'm working on bringing those levels down. I may get a broan or panasonic ERV, but am considering first trying the fresh air intake option on a santa fe ultra dehumidifier. In the winter they can operate in fan only mode to bring in fresh air through a merv 13 filter, and the rest of the year can dehumidify fresh air. It wouldn't provide the energy saving aspect of an ERV, but if already needing a dehumidifier it could be worth starting with that and then if an ERV is still needed they could even be ducted together.
I’m happy you’re enjoying my content 😊 Here are my thoughts about ventilating dehumidifiers: they are a good option for ventilation when the outdoor temperature is between ~55 and ~75F. But if the temperature is any colder or hotter than that, they would bring air that is too cold or hot air into your home. Further, they’re designed to deliver a lot of airflow: the Santa Fe compact70, their smallest model, is rated for 150 cfm, so that’d be a lot of cold air when it’s super cold outside. The air is so dry when it’s cold outside, that the dehumidifier wouldn’t be running, and wouldn’t produce heat to offset the cold (fan only mode). ERVs are of course designed to ventilate in such temperature extremes. It depends on your climate, ultimately. Best option for most people is ERV+dehumidifier though. Experiment!
Hi all! I’d like to mention that even if you live in the desert, you may still need a dehumidifier to supplement your ERV! Even arid regions can get humid during certain times of year.
Outstanding content - thanks! One idea you may not have explored: In the event that you are building a new house or doing a deep remodel, you can elect to use clay plaster (not lime plaster or drywall). Clay-based plaster is an ancient technique that has been used to passively control humidity for thousands of years. It was recently revived by Geoff Lawton in the Greening the Desert project in the Dead Sea. By replacing 80% of the lime in plaster with Bentonite clay, the walls act as a hydric buffer (not my terms, honestly it's the engineers who name these things). When the air is damp, the highly hydrophilic clay particles in the wall absorb moisture like a sponge. When it is dry, the walls dry, releasing moisture into the surrounding air. Result: the indoor humidity settles in at around 45% to 55% regardless of the humidity outside or inside the home. This technique is used in Japan (a very humid temperate rain forest) where the problem is atmospheric humidity, and at the Greening the Desert project in Jordan, with an annual average humidity of less than 20%. This technique produces a lovely wall (decorators call it "Venetian plaster" it's quite on-trend at the moment). The largest challenge is finding plasterers. Plaster on lath is cheaper than drywall (materials cost) but more expensive labor costs (it takes longer and you need a higher level of skill). But, it's still only about 10% to 20% more than level 4 drywall, and you don't have to buy or power expensive mechanical humidity control equipment. To my mind, the set-it-and-forget-it nature of a passive self-regulating system that never needs maintenance or power, makes it worth the extra up-front cost. I would love to hear your take on this technology, as well as other recent tech revivals such as GAHT (ground to air heat transfer) systems, rocket stove wood heating, and Russian masonry wood fired heaters.
Thanks very much Linda! Clay plaster does sound very intriguing - I love the idea of not relying on mechanical devices for humidity control. I'll put clay plaster on my list of topics to dig into. My only concern, which may be unfounded, is about silicosis, a long-term lung disease caused by inhaling crystalline silica dust found in clay. That could totally be a non-issue here, but I'm curious. Anyway, thanks again for your interesting comment!
Or you could use wool for your insulation. Wool not only filters the air but also can hold a lot of water so it acts as a humidity buffer.
@@GeraldLeenerts I looked into wool insulation, but it is SO much more expensive than cellulose. I'm building in the Arizona desert (high in the mountains, away from the baking heat of Phoenix). I will use double-wall construction, with adobe on the outside, a 2.5" gap, and a clay plaster interior wall on 2x4 framing. So the final wall will be 16" thick. I seriously considered blown-in rock wool, real sheep wool, and cellulose. Cellulose wins hands down as the low-cost option. It doesn't have nearly the humidity buffering capacity of wool {sigh}, hence my desiccant built into the walls design.
@@HealthyHomeGuide 😯 That hadn't occurred to me. Wet clay isn't the problem, it's the clay dust that's the problem. 🤔 Since this is a single installation I will be sure to insist on good masks for everyone involved with mixing the clay into plaster. Thanks for the heads up! I can't wait to see your research.
@@lindacgrace2973 Glad to hear you went with cellulose, as it is a carbon negative product compared to rock wool.
I've built a passive addition and working on remodeling our house to be passive as well here in Phoenix. So completely different climate but there is some overlap. There is a pretty good group of folks here if you ever need to bounce ideas around.
You can make an ERV by using plates that are air barriers but vapour permeable, rather than plastic. Materials like Ametalin vapour permeable wall wrap might work for DIY
My new favorite channel !!!
That's awesome, thank you!
You are an honestand and admirable to admit you learned and needed to course correct. Kudos to you! I am curious if your horizontal orientation prevented any partial condensation and drain off as all the commercial ERV/HRVs seem to orient the core vertically such that gravity can drain any condensation in channels as the dew point is hit.
That's very kind! I feel that I owe my viewers my full honesty and authenticity.
Good question. I do believe that the horizontal orientation played a role in condensation pooling a bit. However, the level of condensation never got out of hand, and funnily enough, I couldn't see much (if any) mold growth inside the HRV, probably because I kept it constantly running, so constant airflow. If I had used an air conditioner in the room the HRV was in, I probably would have seen worse condensation.
Interestingly, after removing the HRV, I actually tested some simpler fresh air intake systems, and they also introduced too much moisture into my house. So I don't think it was the HRV itself per se causing the mold issues, more just the practice of ventilating without controlling water vapor.
That's also why the fridge drys out food faster than the bench
100% agree with you. I don’t understand why the industry advises the opposite in all their specifications. I just finished a new house and installed 2 ERV’s with resistance from the HVAC supplier. Fortunately I have taken classes in physchrometry over 20 years ago and that knowledge is still paying off.
I salute you! I feel that psychrometrics is the #1 subject that everyone interested in creating a healthy home should understand.
It is such a huge problem that the HVAC industry is largely unaware of the dangers of using HRVs (especially without dehumidification) in humid regions. The HVAC industry also unfortunately heavily favors people with ducted systems in their homes. I hope to solve these problems someday.
Ouch! Yeah, living in the uk we know all about damp air :( . Lots of older houses that have been 'half fixed' ie made 'warmer' by using double glazing and sealing drafts appear to be suffering with damp issues.. We certainly are. So HRV is definitely not a solution!
Thank you for the video! Can I make a suggestion? Explain things in plain language first and then note "that's called latent energy recovery". Otherwise we have to try to remember the labels while you fill in the details.
Thanks for the tip!
Why no UV lamp to kill mold in your HRV?
Your girlfriend and you have such great energy!!!!She can Rhyme......a little...lol
Hahah thank you!!
Imperial units, caramba!
I want to avoid dry mucus membranes/sinus etc during winter - huge problem for me. Is what you are saying this?:
INSTEAD of having a bit colder temp 18C AND use humidifier to get up to 45% RH ---> JUST increase temperature to 21C (And humidity will come along anyway)
Thanks for the question. No, that's not what I'm saying. I recommend that you watch my video on humidification titled "How Healthy is Humidifying REALLY?" It should answer your question.
Good follow up video. My house is good for humidity, but my chicken coop is too humid and I'm working on solutions to that now. Dehumidifiers are a tricky bet there because of all the chicken dustiness.
A MERV-13 filtered dehumidifier such as a Santa Fe Compact70 could likely handle the chicken dust no problem! Though you might have to clean the pre-filter somewhat often. Have you considered this?
Definitely pre-filter + filter. There must be a reason commercial solutions use more than one filter in series. Big particles don't clog the fine filters too soon. Also, you can usually wash a coarse filter once. And can buy coarse filter material "blankets" and just cut to size
I'm in the early stages of addressing the issue, so I haven't delved too deeply into any options. The humidity issue is of my own making. I decided to re-route my radon vent into the chicken coop to keep them a bit warmer in the winter and cooler in the summer. The air blowing out is always about 55 degrees F. But it's also very humid. I knew this going into it and figured I could try to address the humidity issue once it was set up. A total solution for it is to simply run the air through a radiator in the coop and then vent it out (only having transferred some of its heat, but not the humid air itself). I may go that route. I'm on a fixed budget for electricity usage because I'm running on a solar voltaic system. So trying to figure out what approaches can work with the least electrical burden. Thanks again for this video! @@HealthyHomeGuide
Wow, that sounds fascinating to run the air through a radiator and vent it out (only having transferred some of its heat, but not the humid air itself). I agree that a dehumidifier wouldn't address the underlying issue. I like your thinking and I wish you luck. @@PraxisPrepper
I'm fairly fond of your thinking style too - which is why I keep checking out your videos. I didn't even know ERVs were a thing until your video.@@HealthyHomeGuide
Would this introduce the same amount of humidity as putting a fan in front of an open window? Or more ?
This is a smart question. If we're assuming that both the window fan and the HRV are producing the same airflow, then yes, they would introduce the same amount of moisture.
After removing the HRV, I actually tested some simpler fresh air intake systems, and they also introduced too much moisture into my house.
Anyway, positioning window fans so that they actually produce decent airflow is actually an art! Check out this video to learn more about it: ruclips.net/video/1L2ef1CP-yw/видео.htmlsi=8igAC-mCHH1mReqw
10 grains per pound = 1.42857 grams per kilogram
Thank you!
Thanks. Given he was using a shot glass to illustrate the quantities I wondered if he was being cute & talking about whiskey. Then I realised... Imperial units... so bad their theme tune is used for the Emperor in Star Wars ;-)
thanks for the video, really very helpful ;-)
Happy to help!
Do you know of any ERVs that are sized for a single room? I'm planning on using a mini split heat pump as cooling source, but I suspect that with a well insulated room it won't operate enough to dehumidify the room.
To my understanding, the ERVs are a similar concept as the HRV, but they use a rotating wheel with desiccant in it. The desiccant absorbs the humidity from the humid side, and the wheel rotates it to the dry side where it dries the desiccant and puts the humidity into the air. Very simple.
it's a bit more complex than that in practice, but yes, basically.
Hey.
Although making ERV out of cheap HRV won't be easy, I don't think it would be unfeasable or too cost inefficient.
With the design you made, well firstly you'd need actual countercurrent in the heat exchange unit - your design goes in 90° fashion, which also lowers efficiency.
Once you have this solved, you'd only need water transport material - wick (could be any textile) that would transport water from one end to the other.
Simples thing I can think of would be either textile or steel mesh added on the side wrapping around the inlet-outlet and on throughout the length of the exhanger.
That material would need strong capillary action, so microfibre "quick drying" towel would probably be the best.
Both would pickup the condensation and transfer it to the other side, where it would evaporate to dried out air - this would work both ways.
If done properly, this wouldn't affect efficiency, but you'd get moisture transfer.
The proper countercurrent construction would likely increase the efficiency anyway already.
Other, more advanced improvement I can think of, is making 3 countercurrent exhange units inline, with inside/outside separated in chambers between them, with 2 or 3 wicks running between inside/chamber/chamber/outdside in either alternating or linear fashon, so that moisture exchange would also be gradual, but I think it would not do very much, since the moisture transfer would only occur at dew point.
Moisture control is an interesting topic. In a tightly sealed construction like a passivhaus (or similarly built), I hear that even with an ERV it's not enough to regulate moisture. That's often because the minisplits that are typically used to condition and heat such buildings can't remove enough moisture as they are sized correctly for the passivhaus type cooling load, but that sizing will make them undersized for the moisture removal requirements. So they can't deal with it by themselves, and one does wind up needing a dehumidifier for the humid climates. But the resulting advantage is that (with some effort) the end result is a house microclimate that can be quite precisely controlled.
You're absolutely right about all of that, and that's well said!
he got paid to encourage you to buy that crap. Folks...just ventilate your homes by opening doors and windows when is cold in the morning (during summer) and warm in the afternoon (during winter) and then use your air conditioner/furnace few extra minutes to compensate for lost energy inside your home and....that is it. An outside thermometer showing relative humidity will help and its just around $10. ERV installation cost is $3 - 6 grand, dehumidifier install cost for whole house is can range $2.5 - 3.5 grand. You will never recover cost of those devices and you will pay more for electricity. ITS JUST NOT WORTH IT....but it's just my opinion. HVAC industry come up with worthless gadgets all the time and they try to make money on it. Some of their product are good but rest of it is just pure...and expensive junk.
No, I was not paid to tell you to buy the items in this video. If my content is sponsored, I will always clearly disclose that. None of my content is sponsored yet. I make these video because I've suffered from environmental illness, and I want to help ensure that what happened to me doesn't happen to others.
I've tried your ventilation strategy and it did not work for me - I live in the northeast US. Opening windows is often not a healthy or reliable option for diluting the air in one's home. For one, outdoor-generated particle counts are often surprisingly high. Get a particle counter and test it for yourself. Though it does help to dilute the concentration of VOCs and CO2, opening windows often RAISES the overall particle count. Also, there often isn't enough natural airflow through windows - it's inconsistent. Also, what if it's too humid outside? Too dry? Too hot? Too cold? Using an energy recovery ventilator is far superior to opening a window.
I have videos where I demonstrate DIY installs of both an ERV and a dehumidifier. It doesn't have to be as expensive as you say, though it usually is for a professional install. For those on a tighter budget, I also have a video where I show how to build a DIY fresh air system for a fraction of the cost of an ERV, but of course, without the energy recovery benefits.
I live in a similar clime to you, I haven't constructed it yet, I intend on using your DIY HRV design. Learning from your mold disaster, I am going to see if I can incorporate some form of charcoal, or likewise inexpensive filter inserts for probably at intake/exhaust from the outside.. I feel like it would help, but also decrease volume.
Just my idea, and 2 cents.
The mold issue primarily occurred in my home itself. This was from the humid air the HRV was bringing into the house. Some amount of mold is everywhere, and whether or not you filter the HRV (which I did), mold will grow quite a bit in humid conditions.
I was finally able to install and run my Broan ERV on Friday, waiting for a break in the rain to install the inlet and outlet through the side of the attic. Since my heat pump's air handler uses 500 watts to run I gave the ERV a simple dedicated duct system, pulling stale air from the two upstairs bathrooms and sending fresh into the hallway between the three bedrooms and near the upstairs HVAC air return so when the heat pump is on it will help circulate fresh air through the house. To keep from having to constantly change tiny filters I installed a larger insulated in-line filter to the fresh air supply coming to the ERV. ~100cfm only takes 44 watts per hour.
It was so nice watching bedroom CO2 drop from 1600 to the 700s. I installed a Tamarack Perfect Balance air return in the bottom of one bedroom door so far and will be doing the rest soon to help keep air moving through the house even when doors are closed.
Thanks for sharing your setup and helping me feel like setting up an ERV would be worthwhile even without having ductwork go to every bedroom.
Fascinating! Thank you for sharing your electricity usage and for the tip of installing a larger in-line filter. That little MERV-13 filter inside the Broan ERV is annoying to change for sure.
Your configuration is super cool. Email me if you’d like to be featured at some point.
I'd say a mixture of the old rotating ERV should be possible with your same design or similar. But yea the new ERV are using membranes that actually let about 50% of the moisture pass through the material.. so that type of material isn't feasible for regular people to get. At least no long term lasting stuff.
You could build one out of cotton I guess, but it'd have to have much lower air flow and be much bigger unit lol
I work in the building HVAC arena (P.E.), specializing in energy reduction and comfort improvement for K-12. Yes, everyone should know more about psychrometrics - but it will never happen.
That's very cool, welcome! You're probably right. All we can do is keep spreading the psychrometric gospel. I do think cheap little hygrometers that display the dew point would also be helpful.
I'm enjoying digging through your videos as I recently purchased an Aranet4 CO2 monitor and realized my bedroom CO2 levels can approach 2000 so now I'm working on bringing those levels down. I may get a broan or panasonic ERV, but am considering first trying the fresh air intake option on a santa fe ultra dehumidifier. In the winter they can operate in fan only mode to bring in fresh air through a merv 13 filter, and the rest of the year can dehumidify fresh air. It wouldn't provide the energy saving aspect of an ERV, but if already needing a dehumidifier it could be worth starting with that and then if an ERV is still needed they could even be ducted together.
I’m happy you’re enjoying my content 😊 Here are my thoughts about ventilating dehumidifiers: they are a good option for ventilation when the outdoor temperature is between ~55 and ~75F. But if the temperature is any colder or hotter than that, they would bring air that is too cold or hot air into your home.
Further, they’re designed to deliver a lot of airflow: the Santa Fe compact70, their smallest model, is rated for 150 cfm, so that’d be a lot of cold air when it’s super cold outside. The air is so dry when it’s cold outside, that the dehumidifier wouldn’t be running, and wouldn’t produce heat to offset the cold (fan only mode).
ERVs are of course designed to ventilate in such temperature extremes. It depends on your climate, ultimately. Best option for most people is ERV+dehumidifier though. Experiment!
Thanks for the video here we have 82% humidity all year round so head exchange probably wouldn't be the best