Air exchanger

[Dave Turpin]

An air exchanger is basically an air-air heat exchanger for forced air circulation systems. My house (that is to say, the house that I am NOW buying since the creek house fell through) does not have one.

I cannot find out much performance information on them. Is there any way to figure out how much energy I can save by using one (without having to resort to lengthy heat exchanger calculations)?

What are the best systems out there? I see some simple ones, in different sizes, as well as units with built-in humidifiers and HEPA filters.

[Rob Beckers]

Hi Dave,

Are you talking about an hear recovery ventilator (HRV)? These units exchange outside and indoor air, while recovering (some of) the heat in the indoor air before expelling it outdoors.

First question would be why you think your house needs one. An HRV is only needed if the house was build very 'tight', with few air leaks. Sadly, the vast majority of houses, even the ones build today, are so leaky that an HRV is just a waste of money. Far more air gets exchanged by holes in the house than the HRV would. Sadly, my own house falls in that category as well :cry:...

-RoB-

[Dayton Johnson]

I was told that HRVs were mandatory in all new homes in Ontario..right or wrong?

[Dave Turpin]

You're right. The house I am buying is old and there probably is no hope of me sealing it up as airtight as newer homes.

My first project is going to be sealing, sealing, and sealing some more. Then 10 more inches of attic insulation. And the solar panels I am currently building.

[Rob Beckers]

Don't know about the requirements for new construction, my 23-year-old house is a leaky tub... And that's after fixing the worst holes...

Dave, it may be worth spending the money to get a blower door test done. This used to be subsidized through the EcoEnergy program, but unfortunately that has gone the way of the dodo for residential housing. It will give you a baseline, so you can see after upgrades if you're "there", or if more is in order. It will also tell you if there's any point in adding an HRV at this time.

-RoB-

[Dave Turpin]

I read about that. There are a few firms here in Seattle that make this sort of thing their business. Sort of like a house inspection but for saving energy instead of finding what's wrong with the house before buying it.

[Russ Bailey]

My house is all concrete & block fill with insulation and stucco cover - fairly tight though no one here has ever heard of a blower test.

I appreciate the HRV - saves a lot of energy during heating and cooling seasons - the rest of the time it just moves air out of more moist areas to prevent mold getting started.

I found the claims by the manufacturers a bit difficult to understand and many of them harder to believe.