from Patricia in Bowler, WI:
#201
For many reasons I am unable to install a ground-source (geothermal) heat pump on my property. I am considering installing an air-to-air heat pump which Hallowell says will heat my home down to minus 20 degrees! Other heating contractors say this is impossible and I will need supplemental heat at about 25 degrees. Assuming the air-to-air heat pump will work, what will this do to my electricity bill and carbon footprint? Presently I am using 1,400 gallons of LP gas per year in my recently built (2003), well-insulated home which has many high-efficiency Anderson windows. I was told that the Hallowell air-to-air heat pump would increase my electricity usage by about $90 per month. I presently use 450 KWH per month or 5400 per year. I think the increased electricity usage would be another 5400. Since most of our electricity is produced from coal, how would this change my carbon footprint?
Read on for your answer.
Based on the findings of the Energy Center of Wisconsin in 2000 (Emissions and Economic Analysis of Ground-Source Heat Pumps in Wisconsin 201-1), using a ground-source (geothermal) heat pump would increase emissions (or carbon footprint) of a home unless the heat pump could achieve a heating coefficient of performance (COP) of 5.1. The same would be true of an air-source heat pump. A lot has changed since 2000, including the percentage of coal used for electricity in Wisconsin, but it is likely that the COP breakeven point is still at a COP of 5.1. This COP is not feasible in most applications.