Not sure what you’re referring to when you say “You’ve got it all wrong.” From what I can tell, you’re talking about how to heat your house during the winter. And yes, my HRV does reduce my gas heating cost, but the electrical charges are higher than the savings, so the net outcome is that it winds up costing me money during the winter.

During the summer it’s a slight win, since I’m paying for electricity to cool the air w/my A/C system.

– Ken

I have the same HRV, I had it put in back in 1998, it quit working 2 months ago. I pulled the curcuit board off and found the same as you- relays appeared burned and non-working. In my case, the relays did work, they had lost contact with the board conductivity strips. I could see the burn marks where the relays were soldered on the board. Took it to my barn, tried to repair the solder joints but that didn’t take. So I soldered a jumper wire between the two points and it took right off working fine. I also called my local Carrier dealer, cost for new board was $750. For that much, I can get a few relays from Radio Shack and have a working unit for $5 and a little solder know-how. Really dusted me to know how Carrier backed up it’s product. I have Carrier A/C, that is working well, but this board issue has left a sour taste in my mouth for Carrier equipment. Thanks for your original post, hope things are going well for you now.

gary
Richland, MI

One bit of advice, at least if you’ve got a two-story SIP house, is to ensure that (a) you have a two zone system, and (b) you can configure the HVAC controller to ensure that the fans are running some reasonable percentage of the time (e.g. at least a 15% duty cycle).

If you don’t do this, then the air in house tends to stratify. The situation we were running into during the summer was that the A/C wouldn’t run during the day, but suddenly at midnight it would start up. Which was very confusing, since the area we live in has low night-time temperatures (e.g. 50°F) in the summer, even if it reached 100°F during the day.

After some head scratching and measurements, eventually it became clear what was going on. The SIP house is like a well-insulated ice chest that’s left out in the sun. During the day it warms up slowly, which is great. But eventually, because it’s so well insulated, the energy (heat) that’s accumulated inside the house during the day won’t escape quickly when the outside temperature has dropped. This energy eventually flows up to the second floor as warm air, and the temperature finally gets high enough to trigger some A/C activity.

A whole-house fan would help here, but due to allergies that’s not an option for us. So I wound up doing two things.

First, I bought an AirCycler, which is a 3rd party unit that attaches between the HVAC thermostat and the HVAC controller. It can be programmed to ensure that the fan runs at least X% of the time. Using this, I could keep the house air mixed so that we didn’t wind up with all the warmer air upstairs (where our bedrooms are located) at night.

Second, I changed the timing of the thermostats to really cool the house at night, down to 55°F. This was fairly efficient, since the outside temperature is so low then as well, which means the condensor for the A/C doesn’t have to work as hard. By pre-cooling the thermal mass of the house, we could get through most days without any A/C during the day, until we started the cooling cycle again at around 10PM.

Hope this helps,

– Ken