HVR, when to use it????

[copterdoctor]

So we have a 5+ star energy rated house. It has a HVR system in it.. apparently it is an air recirculator <sp>...
it is different from other HVR systems I've seen, as is uses the regular heater ducts, and not it's own dedicated ducting system.
we were told it uses heat from the exhaust from the central heater.. using a shroud type system. kind of like what is used on aircraft for anti carb ice...

my question is, when is it best to use the HVR? we were told if our windows fog up, we should use it.... well, we've NEVER had fog on our windows... and it was quite expensive to have this system installed... (required for the 5+ rating) so I figure we should be using it.... otherwise, what is the real point of even having it.....
any advice or suggestions????

 

[keweenawbee]

My understanding is they refresh the air in your tightly insulated home for your health, and recapture heat/cooling energy that would normally go out your flue. So I would think it should be used all the time, but I could be wrong.

 

[copterdoctor]

My understanding is they refresh the air in your tightly insulated home for your health, and recapture heat/cooling energy that would normally go out your flue. So I would think it should be used all the time, but I could be wrong.

i would think it would "take out" a bunch of the warm air, making the heater run a lot more... I live in Alaska, and our house is heated with LPG, at 3.60 a gallon. so our winter heating bill is EXPENSIVE, even in a 5+ star rated house...
but, you may very well be correct...

 

[cghsparky]

This is how most work but some have electric heaters in them-
http://www.lennox.com/pdfs/brochures/Lennox_HRV-ERV_Ventilators.pdf

 

[Hlidskjalf]

HRV's are usually left on all the time. Tight structures need fresh outdoor air.

 

[copterdoctor]

thanks for the link sparky.... one thing I don't understand... Our house seems REALLY dry... almost like we need a humidifier.. but it says I live in a region (Alaska), that "requires" an HRV system... like I said b4, we've never had our windows fog... and I'm curious how much more our heater will be running... if any...
I just don't understand why the link says I'm in a "required" area.....

 

[Weedwaka]

Our HRV runs all the time. With radiant heat we have no other fresh air make up. Its badass. If we have it off in the winter, we would turn into frogs.

If you have a furnace, your probably getting your make up air from that at ambient temp. Is it possible they installed the HRV just for the 5 star rating and not because it was required for your situation ? I would want all my make up air running through the heat exchanger in the winter especially in alaska. Makes a HUGE difference.

Also, there are two types of exchanger. Post your model and part number. One exchanges teh air recovering heat (HRV) and the other does so more with humidity ( cant remember designation ). How is it connected to your furnace ?

Really cold air is dry. If your furnice is running in tons of dry air into the home, thats your issue. My brother just installed a humidifier in his new home in 108 mile ( pretty damn cold ). Combo furnace and wood heat.

 

[nate379]

You must have some really high end windows if they don't fog or the humidity is very low. You can get a humidstat at Lowe's or Walmart for around $5

I have Alpine windows from SBS and they ice up pretty bad if I don't set my humidstats (to the bathroom fans) to at least 30% or lower (see pics)

I don't have a HRV, just a poor man's way of doing it.... both bathroom fans are on humidistats and I have a vent in my hallway that opens to the attic. When the fans are on if pulls fresh air from the attic into the house.

Any reason you are using LPG? Pretty much everyone I know that doesn't have nat. gas available use wood or fuel oil. Fuel Oil is $3.10 a gal right now which is the highest I have seen it in a while. When I bought 250 gals a few months ago it was $2.90

 

[oldgoaly]

Nate,
That looks like air leakage in, probably from a poorly shimmed window frame. Plus that also show a negative indoor pressure. It sounds like they sold you a good system on paper but it may not be set up and balanced for your house. If all your windows leak like that the window installers or the contractor did something wrong.
Will your power company do a energy audit? for free/cheap? Too tight of a house leads to higher levels of carbon dioxide and monoxide. A slight positive indoor pressure is what some say is the best. bin ladin and friends(the oil companies) don't need more money. tt

 

[copterdoctor]

It is a Venmar AVS Solo 1.5 HVR

and yes nate, we have VERY nice windows. The front of our house has 6 really large windows, so we opted for very nice ones..

I'm not sure you can have heating oil and still get the 5+ star rating, but I may be wrong. Or it may have been because we have an FHA loan. I know there was some reason why we didn't go to oil, but I can't remember....

 

[jklingel]

"HRV's" that recirculate are just driers, are they not? does this thing actually exhaust? as far as i know, a true hrv controls intake and exhaust air, via a heat exchanger, w/ dedicated ducting; otherwise, it is just phuttsing with the air. i don't think being 5-star has nothing to do w/ how you heat or whether or not you have an HRV; we don't have one and are 5-star, which refers to energy usage. if you are super dry, you may have more leakage than you think. have you had a blower door test done? btw: i don't think the quality of window has a great deal to do w/ condensation. even the best windows are about r-7, center of glass, and i believe they will condense if the humidity is high enough. yes, it takes a slightly higher humidity to condense, as the glass is warmer than crappy windows, but the panes are still relatively cold. your good windows likely seal the drafts well, and may have argon or xenon (?) in them, and a high solar heat gain coefficient glazing. good windows in cold places are a good investment, imo. j

 

[Cast Iron Nuts]

Copter doctor

Have you confirmed that the unit is actually not running these HRV s when set up are normally set to run on low speed ventilation continuously. Some HRV s can be very quiet when running. Check the outdoor hoods for any airflow. Not sure on what type of controller you have but you it should be capable of disarming the the low speed function so the unit will then only operate when switches or timers are activated.

Would like to see how this system is ducted back into your forced air heating system if you could post some pics. Might be able to give some better insight.

Typically the smaller the house the tighter the envelope of the structure.

 

[copterdoctor]

we were told we had to have the HRV installed to get 5star PLUS...
yes they did a blower door test, passed with ease apparently...
here's some pics....

 

[sneezer41]

If I followed the pics, it is ducted into your heating system, I would think it should be 'on'

I would get a short course from the installer, and if he just repeats what he said before, find a more expert expert.......My only concern would be that you are ventilating without the heat recovery without it running

 

[copterdoctor]

If I followed the pics, it is ducted into your heating system, I would think it should be 'on'

I would get a short course from the installer, and if he just repeats what he said before, find a more expert expert.......My only concern would be that you are ventilating without the heat recovery without it running

can you see pics? having upload issues.... waiting on imageshack right now...

 

[copterdoctor]

 

[Weedwaka]

What do you have for a wall control. Our Vanmar eko 1.5 came with a wall mount programmable thing that tells you what its doing all the time.

 

[copterdoctor]

What do you have for a wall control. Our Vanmar eko 1.5 came with a wall mount programmable thing that tells you what its doing all the time.

when I push the button, even "double tapping it" the HVR comes on, and stays on.... you have to push and hold it, to turn it off...

 

[cghsparky]

Most i put in are controled with a humidistat that also turns on the furnace variable speed blower on the lowest speed.