How do Heat Pumps Work?

As you are aware, Dominion is committed to helping Virginia meet its energy conservation goal, and two of the new conservation programs are focused on customers who own heat pumps.

But, what exactly is a heat pump?  Knowing how a heat pump works makes understanding why getting a tune-up or upgrading your unit is a wise idea.

After searching the internet for a comprehensive, yet detailed, description of how a heat pump works, I point you to How Stuff Works: How Heat Pumps Work.  Their description starts off high level and then dives down into the details.