Heat pumps have annually outsold gas furnaces for several years now, and with the recent introduction of more high-efficiency, cold-climate, air-source heat pumps, that trend is likely to continue.

Mike De Socio is a CNET contributor who writes about energy, personal finance, electric vehicles and climate change. He's also the author of the nonfiction book, "Morally Straight: How the Fight for ...

Homes built after 1950 or so are typically heated with either hot air blown through ducts or hot water pumped through baseboard heaters. Older homes often have cast-iron radiators, which produce heat ...