Hey Guys, I need some advice. We are building a 48 x 32 3 car garage with suite on the top. It is to be well insulated with ICF bottom ( garage ), insulated slab, staggered stud 2x8 walls up stairs etc. Because our winters are long and cold ( reaching -25 or -30 c ) we will be loosing a lot ( I think most ) of our heat via the fresh air makeup system. Is it worth while to look into some type of air to air heat pump to utilize the heated air that is being evacuated from our suite to pre heat the fresh air a bit ? Any suggestions would be greatly appreciated.

Why does the forum remove all the formating in the text ? Sorry first post.

Ww,
Had a similar question about putting an ASHP in an attic. My concern for that idea and yours is the same; do the BTUs available = the number of BTUs required for extraction? I don't believe they do.
In other words, while your system would work in principle it would work only for a very small system (not = to heating incoming air).
A better question might be "who makes the best ERV?" These systems if you are, unfamiliar, heat incoming air with leaving air recapturing a significant % of BTU's in discharge.
Where do you live that your winter lingers at -20F? We touch on those #'s in MI but only briefly.
Good Luck,
Joe

This is old, so increase the numbers accordingly.  Also note that some HRVs draw 500 watts (around $500.year).


John Bower (1995)¹ calculated the cost for 80 CFM of continuous balanced ventilation in several U.S. cities, including Minneapolis, Minnesota, with and without heat recovery. A typical annual cost of 80 CFM of continuous ventilation was calculated at $86 with heat recovery and $188 without heat recovery. Of these amounts, approximately $42 is the cost of the electricity to run the 60 W fan).²

We are in the Okanagan Valley in British Columbia. Temps reach about -25c but stay for months around -15 c - -20c .

What about a heat exchanger using a cross flow radiator type assembly ? I wonder if this would pull off enough heat from the vented air to get the incoming air around 0c in the winter ?

http://www.iaqsource.com/category.php/heat-recovery-ventilators-hrvs/?category=945

I should add that these systems vary in eff . so some specific product research is required

I would also recommend a blower door test to make sure that the infiltration you already have is not sufficient

Excellent link, thanks !!

I wonder what would make an HRV / ERV draw 500 Watts? Definitely something to watch for.

I agree with the advice to apply an ERV / HRV in this situation.

I was going to comment on that as well. I know our HRV pulls 70w in low with both intake and exhaust fans running. Do some have heaters to defrost? Ours just shuts off the intake and defrosts with exhaust air.