Is a HRV the way to go?-installed/update

[bkelly]

Im Looking at getting a HRV system to help rid my high humidity , the house is moist, windows are full of water mold forming this winter, and all the cabinetry is swollen. I got close to 300 gal of salt water in the house all in the basement. The house would be fairly easy to plum in the HRV and we have a new high efficiency furnace. Ive read most people in BC/AB are happy with their HRVs,
Is this the right choice or is there a different way to deal with the problem, while keeping my tanks. IM in Kelowna.
Any input would be appreciated.
Thanks.
Brent

[e46er]

As a heating guy
Yes

[Coleus]

I would say yes with or without a fish tank. I really like the fresh air i get from it

[Stones]

I installed a Vanee 90HV-ECM last fall due to the same problems you are having. The previous owners of my house should have installed one years ago as all of the windows frames had black mold on them and had suffered major water damage. After moving in and setting up my 225 galllon aquarium, it was absolutely necessary to install the HRV or my house would have been destroyed by the excess humidity.

I did the install myself and the hardest part was plumbing the exhaust intake vent from my basement to the top of my living room wall on my main level without tearing out any drywall or ripping the flexible venting while doing so. Other than this, the install went very well and after firing up the HRV, my humidity went from >60% down to 30-35% within a few days. I also vented the fresh air into my furnace plenum which is what I'd recommend to anyone doing a retrofit, especially if you have a furnace with a DC fan.

I ended up with alot of small cracks in my drywall and nearly all of my baseboards had to be redone due to the large gaps forming at all the corners and joints. I now have to replace all of the windows and frames in the house as the frames are shot and all of the window inserts seals are gone as well. Had an HRV been installed sooner, this likely wouldn't have been the case.

You won't see a new house being built now without a HRV and this should have been manditory years ago. I'd highly recommend installing a HRV in your situation as a dehumidifier may be the cheaper route, but this is only a bandaid and not a solution for such a problem.

[The Grizz]

I really need to get one for my indoor pool, way more efficient then the stupid system they put in. I have had to replace the motor twice in 2 yrs and now I can find another one because they are out dated.

[toxic111]

You won't see a new house being built now without a HRV

I just have to correct you on this. New houses are NOT being built with a HRV, as this is not a requirement. You would have to request it from a builder. I am in the building industry, and I sure don't see many of them going in at all.

[rayjay]

I just have to correct you on this. New houses are NOT being built with a HRV, as this is not a requirement. You would have to request it from a builder. I am in the building industry, and I sure don't see many of them going in at all.
I believe that depends on just where you are as there can be local and provincial differences.
I put an HRV in many years ago and when I did the research on them, I found that it was a required item for new home building in many places. I'm unable to remember now just where those areas were but I'm sure someone else will chime in on it.
I should have put one in years earlier because I ended up replacing all the windows and doors due to the damage from the excess humidity.
I have a Lifebreath 300DC unit and it JUST works with the approximate 900g of open water I have in the basement.

[blacknife]

Ugh toddler attack, sorry.

[Delphinus]

I just have to correct you on this. New houses are NOT being built with a HRV, as this is not a requirement. You would have to request it from a builder. I am in the building industry, and I sure don't see many of them going in at all.

I always thought it was code for R2000 rated homes but not required by code for any other. Since most homes aren't R2000 it would stand to reason that most new homes aren't having HRV's put in as standard but I can't find a good reference easily that says R2000 code in Canada requires HRV so maybe even there it is not required although possibly "recommended."

Did come across this though in my poking around the R2000 standard for Canada and it's a nice reference that explains HRV (in case anyone's interested :) )

http://www.oee.nrcan.gc.ca/residential/personal/cooling-ventilation/ventilators-fans/index.cfm?attr=4

[Delphinus]

Im Looking at getting a HRV system to help rid my high humidity , the house is moist, windows are full of water mold forming this winter, and all the cabinetry is swollen. I got close to 300 gal of salt water in the house all in the basement. The house would be fairly easy to plum in the HRV and we have a new high efficiency furnace. Ive read most people in BC/AB are happy with their HRVs,
Is this the right choice or is there a different way to deal with the problem, while keeping my tanks. IM in Kelowna.
Any input would be appreciated.
Thanks.
Brent

I had this problem too when I first moved into my house. 6 months in (on a brand new house) the humidity from the tanks caused me all those problems you just listed. And an HRV fixed every one of them.

Even without a fish tank I'd consider having one in my home pretty much forever.

I imagine they work better where the air is dry. Don't know how dry Kelowna is in the winter, but I imagine it's probably dry enough to make a go of things with an HRV. In Calgary where I am, even in the summer, what we call "rain" most other people would call "10% relative humidity" so the HRV works like a snap.

[Delphinus]

Found another useful link .. might as well share it in case anyone's interested. :lol: http://www.joneakes.com/jons-fixit-database/631-Overview-To-HRV-or-not-to-HRV

[globaldesigns]

I have one, so I will also chime in here and say YES! Plus there are other benefits like heat recovery and overall house circulation.

[Funky_Fish14]

I have one, so I will also chime in here and say YES! Plus there are other benefits like heat recovery and overall house circulation.

+1.

We have one in our place... I used to have just over 500gal of water in the house and we never had any buildup. The old house had noticeable humidity buildup with only 1 tank and did not have an HRV.

[Cal_stir]

problem is that newer homes even though they are not R2000 are pretty air tight and HRVs are nec even without a fish tank, unfortunately they are not code in most places

[cale262]

Another Yes here, HRV + 700 fish gal in the house, everthing is good, although I do notice the HRV runs 24/7 in the winter...

[toxic111]

What I was getting at is they are not required by the National Building Code, which is the model code for Canada. I do not know the eastern codes, but in SK, AB & BC they are not required. They are a very good idea as modern homes are sealed too well.

[bkelly]

thanks guys this really tells me id be doing the right thing, Kelowna is dry in the winter, summers not that humid either. Ill keep you posted on the changes with it and how the install goes.

[e46er]

What I was getting at is they are not required by the National Building Code, which is the model code for Canada. I do not know the eastern codes, but in SK, AB & BC they are not required. They are a very good idea as modern homes are sealed too well.
Depends where u are as well
They are mandatory in Vancouver Bc but not the surrounding cities

[sphelps]

My house is new and it has a simple exhaust fan plumbed in from the cold air return to outside. Does the same thing as an HRV but without the heat exchange. I thought about upgrading but I figured I'd leave it for at least a year before I bothered. I have it connected to a central thermostat that controls humidity levels as well with the exhaust fan and the humidifier. I believe most of the time HRVs are controlled either by simple timers, local humidistats or even just a light switch. Anyways I watched the heat bills last winter when I first connected up the exhaust fan and control and I didn't notice any difference in consumption. I have 100 gallons open top upstairs and about the same worth of open sumps downstairs but there is a lot more exposed water surface than a typical 200 gallon system. The thermostat I use also has some other features it uses to limit window frost, not sure exactly but it works and it's a different setting than the set humidity which is still maintained.

So I guess for me I wouldn't bother with the HRV, I doubt the extra cost and install would ever pay off. But it will likely depend on the demand for it but there are other options for humidity control. You should also check your furnace, it should draw in some fresh air when it operates and many times moisture and mold problems are a result from poor air circulation, not always directly a result from high humidity from lack of ventilation exchange.

[toxic111]

Depends where u are as well
They are mandatory in Vancouver Bc but not the surrounding cities

Vancouver does have its own building code too..

[mike31154]

My house is new and it has a simple exhaust fan plumbed in from the cold air return to outside. Does the same thing as an HRV but without the heat exchange. I thought about upgrading but I figured I'd leave it for at least a year before I bothered. I have it connected to a central thermostat that controls humidity levels as well with the exhaust fan and the humidifier. I believe most of the time HRVs are controlled either by simple timers, local humidistats or even just a light switch. Anyways I watched the heat bills last winter when I first connected up the exhaust fan and control and I didn't notice any difference in consumption. I have 100 gallons open top upstairs and about the same worth of open sumps downstairs but there is a lot more exposed water surface than a typical 200 gallon system. The thermostat I use also has some other features it uses to limit window frost, not sure exactly but it works and it's a different setting than the set humidity which is still maintained.

So I guess for me I wouldn't bother with the HRV, I doubt the extra cost and install would ever pay off. But it will likely depend on the demand for it but there are other options for humidity control. You should also check your furnace, it should draw in some fresh air when it operates and many times moisture and mold problems are a result from poor air circulation, not always directly a result from high humidity from lack of ventilation exchange.

After reading through some of the info provided in the links from Delphinus, I'm not convinced an HRV is necessarily useful or cost effective for everyone. There are a lot of factors to consider before forking out the dough for one of these, even if the government is providing some incentives. It really seems to be very dependent on age of home, how well it's sealed & more importantly the climatic conditions where you live in the winter. Seems to me having a code requiring HRV in a place like Vancouver makes no sense. It never gets cold enough long enough for the heat exchange portion of the system to provide any payback, nor is an HRV effective for humidity control in the summer. Well designed exhaust system similar to what sphelps has should work quite well to keep humidity under control.

Not sure I follow how exactly your system works though. The exhaust fan pulls air directly from your furnace cold air return? Is there another fan or at least opening to the outside to allow fresh air in to replace the exhausted air? My house was built in the late '50s and there are plenty of places for fresh air to get in. I have a fireplace in the basement as well as one in the living room, so I need to figure out if exhausting air without providing incoming would cause backdraft thru my chimneys. I also remember when I replaced the furnace in the condo I lived in in Ottawa, new code required the installer to run a simple duct from outside to the furnace to provide fresh air.

EDIT: Just found another link worth checking out. Good discussion on HRV, ERV and some of the pitfalls that may be encountered when considering any kind of ventilation system.

http://www.greenbuildingadvisor.com/blogs/dept/musings/hrv-or-erv

[rayjay]

For me, I went with the HRV rather than the ERV because the Lifebreath engineer I dealt with (factory here in London) said the ERV can freeze up in winter and they never advise ERV when temperatures routinely hit below -5° C in winter. If you don't have that situation, an ERV could be considered, again, depending on just what you are looking to accomplish.
He also did calculations using winter house temperatures and square foot of all open water surfaces and temperature of the water in the tanks to figure out what size HRV would be needed for the volume of my home.
Lastly, he advised me NOT to use the humidistat as when the HRV is not actively running, the air exchange is not occurring and air exchange was important to me to keep pH from dropping too much in the tanks.
In our location, surrounded by the Great Lakes, humidity is extremely high in summer and I certainly don't want an ERV that is going to reintroduce some of that moisture back into the incoming air.

[sphelps]

Not sure I follow how exactly your system works though. The exhaust fan pulls air directly from your furnace cold air return? Is there another fan or at least opening to the outside to allow fresh air in to replace the exhausted air? My house was built in the late '50s and there are plenty of places for fresh air to get in. I have a fireplace in the basement as well as one in the living room, so I need to figure out if exhausting air without providing incoming would cause backdraft thru my chimneys. I also remember when I replaced the furnace in the condo I lived in in Ottawa, new code required the installer to run a simple duct from outside to the furnace to provide fresh air.


The exhaust fan only works when the furnace is on, just like the humidifier. So if the exhaust fan is active it creates a negative pressure and the furnace will draw in make up air from outside. And yes the exhaust fan draws air directly from the cold air return.

[MarkoD]

In my house we have a switch by the thermostat that turns on all 4 bathroom exhaust fans and turns on the furnace. Moisture gone in no time.

[sphelps]

Another thing to check is your humidifier, make sure it's not the source for the moisture problem. Ask yourself how it's controlled and if it makes sense. Often they use a local humidistat that isn't accurate to begin with and it's location isn't effective. Disconnected the humidifier for a while and running the furnace fan more often and observing the change in humidity should tell you if there's an issue.

[mark]

In my house we have a switch by the thermostat that turns on all 4 bathroom exhaust fans and turns on the furnace. Moisture gone in no time.

and all that warm air you spent the bucks heating, which is the purpose of the HRV to recover. Big question is how much that heated air is worth vs cost of unit? Won't bring in the air quality factor.

[wolf_bluejay]

I've had mine for about 2 years now. Just before I installed it I was going through all the eco energy rebates in BC for the new furnace and heat pump, insulation etc. I found that with all the extra air sealing I went from having fogged up windows to where I was having water running down the walls on cold days.
It was nasty, with all sorts of mold issues. So, with the fact that I got a bunch of rebates for the HRV I installed my own. I spent a little under $600 for the unit and installed it myself. I got back about $500 on rebates. So the thing cost me very little.

The problem of wet windows went away. But even more so, me and the family felt less tired in the house, it got less muggy we we had a lot of people over (I kick it onto high then), and smells don't linger in the house, and much less dust. I like it so much that I would put one in a house even if I didn't have the fish tank.

That said, as I couldn't do it with the way my house is, but for my parents place they swapped out the bathroom fans with an HRV. It kicks into high for 30 minutes when you hit the fan button in either bathroom. It dumps the return air into the main living room.

For them, they didn't need to replace 2 bathroom fans at about $200 each for large quite ones so the unit was only a few hundred more. Considering they are on electric heat (and no air exchange in the house) the pay back was there and the comfort level was much better.

I can't see how you could lose with one unless you spent a lot to get one installed.

[Veng68]

Just wondering what is involved in the installation of an HRV unit in a finished basement and a mech room that is in the center of the house? Will I have to take down a lot of dry wall to do an installation?

Cheers,
Vic

[sphelps]

Depends on the unit but you can use your furnace to distribute the air rather than a fully independent HRV. Then you would simply drill one extra hole in the mechanical room wall for exhaust and run the HRV exhaust line from there to the furnace cold air return. The HRV intake would go inline with the current furnace fresh air intake. This way no drywall has to come down, no major modifications.

http://img.photobucket.com/albums/v493/twister55/tool%20info%20sheets/hrv1.jpg

Or even like this:
http://homesmsp.typepad.com/.a/6a00e550bbaeb388340120a71e312a970b-320wi

Of course you need a forced air furnace and it's fan will have to operate when the HRV is on.

[jimbo222]

Wow lots of great info and opinions on HRV/s Here's mine...

We have to keep in mind that a HRV is an AIR EXCHANGER and not only a De-humidifier.
The De-humidification is an added bonus this unit features, or provides.
It is quit amazing how much OXYGEN is reduced in the home and not replaced. You probably dont notice it but you are probably getting tired and sleepy. Your Furnace uses oxygen as it burns, your water tank uses oxygen when it's running, each person in the house is using oxygen, and MOST IMPORTNTLY our aquarium's are using it all up. I guaranty you will have more stable PH if you install a Air Exchanger, usually will go up by .2 or .3.
I realize some homes have fresh air and combustion air intakes to the furnace room but this does not provide air exchange, but prevents a negative pressure in the house.
Personal y I think An HRV is a Very important unit in the climate that we live in. < if installed properly> Not only as De-humidification help but for Healthy Fresh outdoor air.

AS mentioned above aswell make sure that your humidifier on the furnace is installed correctly, especially if it;s a new home. < iv been to too many home's where the humidifier was installed incorrectly and runs anytime the furnace comes on >

The money we put into this hobby... , $700 unit is nothing in the long run, and will save your home from mold.

[jimbo222]

In 1st picture shown above the Fresh air to the furnace must go on the return air duct, and not on the supply air duct shown.If installed as shown the furnace blower will overpower the HRV motor and burn it out .
second picture is better whith both pipes in the return air

[wolf_bluejay]

I have to admit, there was a huge difference in the "tiredness" of my house after the HRV was installed -- so much that I would install it without and aquarium.

And since I forgot to mention it in the my previous post, I used to fight with low PH all the time, and after the HRV it is just perfect without much fiddling. The CO2 levels in you house can build up quite high. In a school building with CO2 monitor it can go from about 400 ppm first thing in the morning to well over 700 later in the day and your house isn't much different. the excess CO2 is what causes your PH to drop and you to feel tired.
In reality the HRV is the same as turning on your bathroom fan and opening a window -- without the 100% loss of heat/cold. Recently I modified my HRV setup to dump the return air directly into our exercise room (treadmill) and we did notice a difference as that room didn't have all that great airflow.

If I was doing an install on a new house where you could run the ducts without ripping apart walls --- exhaust air from the bathrooms instead of fans, and put the return into the main living areas rather than into the furnace (like the photos).


Wow lots of great info and opinions on HRV/s Here's mine...

We have to keep in mind that a HRV is an AIR EXCHANGER and not only a De-humidifier.
The De-humidification is an added bonus this unit features, or provides.
It is quit amazing how much OXYGEN is reduced in the home and not replaced. You probably dont notice it but you are probably getting tired and sleepy. Your Furnace uses oxygen as it burns, your water tank uses oxygen when it's running, each person in the house is using oxygen, and MOST IMPORTNTLY our aquarium's are using it all up. I guaranty you will have more stable PH if you install a Air Exchanger, usually will go up by .2 or .3.
I realize some homes have fresh air and combustion air intakes to the furnace room but this does not provide air exchange, but prevents a negative pressure in the house.
Personal y I think An HRV is a Very important unit in the climate that we live in. < if installed properly> Not only as De-humidification help but for Healthy Fresh outdoor air.

AS mentioned above aswell make sure that your humidifier on the furnace is installed correctly, especially if it;s a new home. < iv been to too many home's where the humidifier was installed incorrectly and runs anytime the furnace comes on >

The money we put into this hobby... , $700 unit is nothing in the long run, and will save your home from mold.

[wolf_bluejay]

Just as I was looking this up -- currently between the BC and federal eco energy rebate program if you get high enough "air sealing" and install an HRV you can get $1375 in rebates. As this doesn't require that you spend MORE than that to get the grant, and buy one for $600-700 and install it yourself you actually can make a profit or spend the rest to improve the efficiency of you house :biggrin:

[bkelly]

well my HRV is in and has been running a few weeks now. Its completely dried out the house. My doors open and the windows are dry. It took a bit of work to get the in flow/out flow pipes insulated so not to leak condensate all over the wall. Were really happy with it , saved the house. I have been bleaching the mold on the ceiling spots and will re paint. It had gotten quite serious. I saved a fair bit installing it myself. All in all a really good choice.

[MarkoD]

glad to hear it worked. i achieved the same results of lower humidity by switching to LED

[KevinK]

bringing this all a bit further, whatsize do you need?

as I need to order and install one before march (to get the grant) I'm reading up a bit,

there are energy star once and gust regular, ok I se that, as the star once use less power. but in between all type of units and brands, it is a matter of CF per houre ore CF per minute.

so now wondering, how much air flow do you need for a particular house size,

would it be like 100CFM is good for 2000 sqft house, 150 CFM is for 2500 sqft house and so on and so on.

cant find this infor 1,2,3

also, would you considder to have one intake in a filter room, ore above the tank (salty air)

[mark]

so now wondering, how much air flow do you need for a particular house size,


also, would you considder to have one intake in a filter room, ore above the tank (salty air)

google "sizing HRV" or look installations manuals for either the formula based on the volume of house or the tables.

my plan is pull the stale air from high point in the house, fresh air tied into force air furnace ducting. I wouldn't pull directly from over the tank as wouldn't think the moist salt air would be to good for the HRV fan motors

[bkelly]

I took my stale from the laundry room and the room linked /beside to my tank room i was going to run more but that was enough to do the trick, i didnt balance it but its an older home so heard thats not as important in older homes due to not being totally sealed. Plus balancers are expensive and i installed myself. I got the Lennox 200 it was the higher volume one but i wanted to up and not worry, my humidity is way lower now. (below 40%), it returns into the furnace up stream of the blower , the blower is wired to the HRV to be on when its on, the air that blows is a little cool when not heated , house is a bit cooler, its only -5 to -10 out.. Ill have to run on low in the summer but this wasnt an issue in the summer , good for fresh air into the home.

[bkelly]

yes the calculators can go by sq foot or average home size base on 3-4 bdr etc. for getting an idea on size of HRV needed, mine was for a standard 3 bdrm home. although i got the size up. Got it through Coral in Kelowna. saved $1500 installing myself. Didnt go for the grants, didnt get the inspections before and after, seemed not much left after. We were in a rush to save the home from damage.

[rayjay]

In my case I spoke with the engineer for Lifebreath here in London where they are made, and he took the square footage of the house, the year it was built, extra insulation of any kind added after the build, and then wanted to know the surface area and temperature of all the open water in my house, to come up with an accurate determination.

[mark]

In my case I spoke with the engineer for Lifebreath here in London where they are made, and he took the square footage of the house, the year it was built, extra insulation of any kind added after the build, and then wanted to know the surface area and temperature of all the open water in my house, to come up with an accurate determination.

much difference from the regular formula for the 0.35 air changes an hour (sqft x height / 60 x 0.35 to give CFM)

[rayjay]

The reason for it was circumstances not normal to most houses.
I had over 1000g of open water in my basement with all the tanks, the brine shrimp operation, nanno culturing and ageing water vessels.
Simple formula just wouldn't cut the mustard.
Also, when I got mine there were hardly any contracters that even understood HRV's and ERV's.
Most of them tried to sell me ERV's which don't work well below -5°C.

[bkelly]

I found that too, the two i talked to in Kelowna didnt know much and what they did new was with HRVs for new homes, I knew what i wanted from Canreef mostly but listened to them and we figured it out.

[mark]

The reason for it was circumstances not normal to most houses.
I had over 1000g of open water in my basement with all the tanks, the brine shrimp operation, nanno culturing and ageing water vessels.
Simple formula just wouldn't cut the mustard.
Also, when I got mine there were hardly any contracters that even understood HRV's and ERV's.
Most of them tried to sell me ERV's which don't work well below -5°C.

most of use aren't normal so why was asking :wink:. Could you work backward, for how many air exchanges per hour was recommended?

[rayjay]

As I don't have the knowledge to properly determine I left everything up to the engineer. I would have no idea as to being able to work it backwards because there are so many variables from home to home.

[StirCrazy]

you guys do all realize that the freeze up problems with ERVs were solved years ago, Although companies still state this to sell there HRV's.... but I do agree for this situation a HRV is probably good.


Steve

[Coleus]

I have nothing to say bad to say about HRV but if you have one installed, make sure you replace your furnace filter more frequent than before else you will have a furnace problem like mine where the safety switch failed because of the filter clogged up

[mark]

As I don't have the knowledge to properly determine I left everything up to the engineer. I would have no idea as to being able to work it backwards because there are so many variables from home to home.

Simply for number of air exchanges, how many square feet is you house, how high the ceilings, CFM rating of your HRV?

[StirCrazy]

I have nothing to say bad to say about HRV but if you have one installed, make sure you replace your furnace filter more frequent than before else you will have a furnace problem like mine where the safety switch failed because of the filter clogged up

shouldent be because of the HRV at all as there is filters in that. if anything the furnace filter should be cleaner as your HRV is supplying your make up air. now if you have your HRV installed what I call the lazy way where it is tied into your furnace ducting then ya it will tax your furnace filter more, but installing this way doesn't make the most efficient use of the HRV system.

Steve

[rayjay]

Simply for number of air exchanges, how many square feet is you house, how high the ceilings, CFM rating of your HRV?

House is about 1280 sq. ft. not counting the basement. Ceilings are 8ft.
HRV is a 300 DCS and the specs are the last line on this page. (http://www.lifebreath.com/downloads/75/MAX%20RNC%20Eng.pdf)