When you think about cooling a hot building, you probably don't think of heat pumps. In fact, you likely think of using an air conditioner instead. But as it turns out, a heat pump can heat and cool, and in some applications, it's preferred to separate heating and cooling systems.

Simply put, a heat pump is a device that uses a small amount of energy to move heat from one location to another. Heat pumps are typically used to pull heat out of the air or ground to heat a home or office building, but they can be reversed to cool a building. In a way, if you know how an air conditioner works, then you already know a lot about how a heat pump works. This is because heat pumps and air conditioners operate in very similar ways.

One of the biggest advantages of a heat pump over a standard heating, ventilating and air conditioning (HVAC) unit is that there's no need to install separate systems to heat and cool your home. Heat pumps also work extremely efficiently, because they simply transfer heat rather than burn fuel to create it. This makes them a little greener than a gas-burning furnace.

There are many kinds of heat pumps, but they all operate on the same basic principle: heat transfer. This means that rather than burning fuel to create heat, the device moves heat from one place to another. There's a key to making this all happen. According to thermodynamics, heat naturally flows from high temperature areas to those with lower temperatures.