Which Is More Efficient: A Heat Pump or a Furnace?

Why there is no simple answer

Comparing a heat pump to a furnace is not as direct as comparing two numbers on a spec sheet. The real result depends on several variables that change from one home to the next. These include system operating time, the cost per kilowatt hour of electricity, the cost per therm of natural gas, the efficiency rating of the furnace, and the HSPF, or heating seasonal performance factor, of the heat pump.

Because these factors vary by region and by household, the only accurate way to compare is to run the numbers using your own local conditions. A local contractor can help, but be aware that some have a bias toward one system for reasons unrelated to operating cost or comfort. Ask questions and look at the math.

How climate decides the winner

Climate is often the deciding factor. As a broad generalization, in most areas of the country an 80 percent furnace consumes about the same amount of energy as a heat pump, assuming operating time and climate are comparable. A heat pump tends to perform well in mild and moderate climates where it rarely needs to fight extreme cold.

In colder regions, the picture changes. When temperatures drop, a heat pump works harder and may lean on backup electric heat, which raises cost. In those areas natural gas is normally the better choice if a gas line is available.

Key efficiency ratings to compare

When you weigh these ratings against your local energy prices, the right choice becomes much clearer. Higher numbers mean better efficiency, but a more efficient unit only saves money if its fuel source is affordable where you live.