Air to Air Heat Exchanger Expectations

Geo NR Gee · 10-18-12, 01:08 PM

Since my home was built to a higher energy standard of the day (late 1990's), and supposedly tighter construction methods, they installed a fresh air duct to the heating system. When it comes on (via a timer), the high cfm bathroom fan in the upstairs bathroom begins. It was set for 10 minutes every three hours. I thought that was a bit excessive.

After I had a energy audit done with the blower door test and high tech thermal imaging device, I know that the house is not as tight and insulated as it could be.

With that in mind what should one expect with a heat exchanger? I found one with 50% efficency on a Mitsubishi unit for sale locally. The unit is only $45 but after reading this, maybe I should make my own?

Piwoslaw · 10-18-12, 11:49 PM

You can build one with efficiency as higher than 90%.
DIY ventilation heat exchanger

Daox · 10-19-12, 07:18 AM

You can calulate the heat you're loosing via that fan running. It might be a lot less than you think. A DIY HRV would improve things though.

10-18-12, 01:08 PM	#1
Geo NR Gee Journeyman EcoRenovator Join Date: Jan 2011 Location: Seattle Posts: 326 Thanks: 109 Thanked 23 Times in 18 Posts	Air to Air Heat Exchanger Expectations Since my home was built to a higher energy standard of the day (late 1990's), and supposedly tighter construction methods, they installed a fresh air duct to the heating system. When it comes on (via a timer), the high cfm bathroom fan in the upstairs bathroom begins. It was set for 10 minutes every three hours. I thought that was a bit excessive. After I had a energy audit done with the blower door test and high tech thermal imaging device, I know that the house is not as tight and insulated as it could be. With that in mind what should one expect with a heat exchanger? I found one with 50% efficency on a Mitsubishi unit for sale locally. The unit is only $45 but after reading this, maybe I should make my own?

10-18-12, 11:49 PM	#2
Piwoslaw Super Moderator Join Date: May 2009 Location: Warsaw, Poland Posts: 961 Thanks: 188 Thanked 110 Times in 86 Posts	You can build one with efficiency as higher than 90%. DIY ventilation heat exchanger __________________ Ecorenovation - the bottomless piggy bank that tries to tame the energy hog.

10-19-12, 07:18 AM	#3
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	You can calulate the heat you're loosing via that fan running. It might be a lot less than you think. A DIY HRV would improve things though. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. Last edited by Daox; 10-19-12 at 07:20 AM..