What's the difference between warm air and cool air? In fact, what does “temperature” even mean? It's stranger than you think. At a basic level, if you increase the temperature of air, you increase ...

The highly efficient devices are the darlings of the environmental movement. Here’s why. By Hilary Howard Heat pumps, which both warm and cool buildings and are powered by electricity, have been ...

I've been haranguing my parents to get a heat pump for years. Heat pumps -- basically air conditioners that also work in reverse, cooling and heating your home ultra-efficiently -- came into my ...