interesting article for anyone looking at variable speed (ECM) furnaces

[Chris Friesen]

I just came across an interesting article that quantifies some of the results from switching to a variable speed furnace blower motor.

The paper is called "Effects of ECM Furnace Motors on Electricity and Gas Use" and is put out by the "Canadian Centre for Housing Technology".

Some interesting points:

--Gas consumption actually goes up slightly due to the fact that you don't have the "waste" electrical head from the motor helping warm the air. By the same token, you save some money cooling because you have less unwanted motor heat.

--Net savings are highest in a well-sealed and insulated house.

--Based on coal-fired electricity, net reductions in GHG emissions due to an ECPM motor are over 900 kg of CO2 a year in all cases (over 1,800 kg of CO2 a year for houses with air conditioning).

--For houses which currently do _not_ run the fan continuously, most could improve air quality through circulation with an ECPM motor with no increase in utility bills. (But also no substantial decrease.)

Chris

[Chris Friesen]

After further exploration, it appears that the more detailed version of the document is here:

There's an interesting comparison for the US done by Lawrence Berkely National Laboratory available here:

The paper indicates that the DC motor doesn't pay for itself except for the colder states.

Chris