EcoRenovator - View Single Post - Warm-air furnace, reducing excess capacity

abogart · 01-15-12, 05:51 AM

I have also been wondering which blower speed I should use to get the most out of the gas that I'm putting in. The main blower has 4 speeds: Lo, M-Lo, M-Hi, Hi. When I bought the house the heating speed was set to M-Hi. Later, I had the idea that blowing more air over the heat exchanger would pull more heat out of the exhaust gases, so I cranked it up to Hi. Then I read something that said that faster air in the ductwork promotes more heat loss through the ducts. Also, I'm thinking that there might be a point of diminishing return in regards to lowering the outlet temp. For example, if the blower were pushing so much air that the temperature rise was only 10°F, would it have any effect at all on the air in the house.

On the same subject, I can adjust the blower-off timing for 90 sec., 120 sec., 150 sec., or 180 sec. I used to think that getting the most heat out of the HE and ductwork and into the house would make the most sense. But I read something that said that the ducts shouldn't be allowed to cool completely down.

I just KNOW somebody is going to tell me to read the manual.

01-15-12, 05:51 AM	#26
abogart Efficiency Afficionado Join Date: Jan 2012 Location: Michigan, US Posts: 68 Thanks: 21 Thanked 6 Times in 4 Posts	I have also been wondering which blower speed I should use to get the most out of the gas that I'm putting in. The main blower has 4 speeds: Lo, M-Lo, M-Hi, Hi. When I bought the house the heating speed was set to M-Hi. Later, I had the idea that blowing more air over the heat exchanger would pull more heat out of the exhaust gases, so I cranked it up to Hi. Then I read something that said that faster air in the ductwork promotes more heat loss through the ducts. Also, I'm thinking that there might be a point of diminishing return in regards to lowering the outlet temp. For example, if the blower were pushing so much air that the temperature rise was only 10°F, would it have any effect at all on the air in the house. On the same subject, I can adjust the blower-off timing for 90 sec., 120 sec., 150 sec., or 180 sec. I used to think that getting the most heat out of the HE and ductwork and into the house would make the most sense. But I read something that said that the ducts shouldn't be allowed to cool completely down. I just KNOW somebody is going to tell me to read the manual.