Heat pumps are not delivering expected cost savings – GreenBuildingAdvisor

Two years ago we took advantage of our state’s efficiency rebate program to install two heat pumps in our 2,200-square foot 1978 split level in southern Maine (6A) – one up, one down in common rooms. We used them as directed by the installer, leaving them on 24/7 at a set temp. We continued to use our 20-year-old oil-fired boiler for domestic hot water and also to warm the bedrooms which don’t get good circulation from the common rooms.

I was hoping the extra efficiency offered by these units would lower my heating costs enough to eventually pay off the $9K investment (that includes the rebate).

It’s not happening. The first year our utility costs (oil and electric) were about $200 less than pre installation. Last year they were actually about the same before the heat pump install.

This year, with oil relatively cheap ($2.85/gallon at my last fill) and electricity relatively expensive (.30/kw), I’ve opted to turn the heat pumps off and go back to oil. 

I’m wondering if others have experienced this issue?

I understand there are many variables here that need to be considered (home construction and insulation, heating degree days, etc.) so this is a very general question. But I am curious if others here have done a similar analysis of the relative costs of these two heating methods.