Here is a comparison of the total life-cycle cost of geothermal heat pumps vs air-source heat pumps that would be needed to heat and cool your residence. To compare as closely as possible, here are estimates for an air-source heat pump system that matches a geothermal heat pump. This heat pump model is the two-stage variable speed. The heat pumps are backed up by a variable speed electric air handler to move the air and for backup heat.
|Installation cost (after tax credit)||$12,700||$18,100|
|Energy cost per year||$1,400||$660|
|Annual life expectancy||15||30|
|Cost of equipment per year||$846||$600|
|Maintenance cost over lifetime||$1,500||$750|
In my comparison (above), the geo heat pump price is higher than the air-to-air, but the geo takes advantage of a 30% tax rebate and the air-source only receives a $1,500 tax rebate. Operating costs favor geothermal, of course. Geothermal heat pumps will last twice as long as conventional air-source heat pumps, and the associated maintenance of them over their lifetime is significantly lower—primarily because there are two pieces of machinery to service instead of one. Additionally, the value of the loop field will remain after the life of the hardware, which adds salvage value to the net worth of the geo. In 30 years, your loop field will be conservatively worth twice its installed cost. This is a significant investment, as well, and one that is not often discussed in ROI analyses. Geothermal heat pumps will provide about 50% of your domestic hot water production and definitely will give you more comfort in terms of operation and reliability.
So, it’s safe to say that your geo investment is better than the air-source investment.