Hey Mr. Green,

My oil furnace needs to be replaced. I’m planning to install a heat pump that works in winter in Massachusetts, because heat pumps are better for the environment than furnaces. I could change the fuel to propane from oil, since natural gas is not available. Would changing to propane from oil also be a better choice for the environment?

—Fran in Sutton, Massachusetts

A heat pump is definitely better for the environment. Heat pumps use only about a third as much electricity as baseboard electric heaters and considerably less energy than gas or oil furnaces. You don’t need gas or oil to operate a heat pump, as it relies only on electricity.

Propane is somewhat more efficient than oil, as it emits about 13.5 percent less carbon dioxide per million BTUs. Propane is also much less bulky than oil and burns somewhat more efficiently: 12.7 gallons of propane releases the same amount of CO2 as 22.4 gallons of oil, while it also emits 13.8 percent less CO2 per unit of heat that it produces.

It wasn’t until recently that heat pumps became efficient enough to operate economically in colder climates like Massachusetts, while they had been in use in warmer areas for quite some time. Click here for more information.