Heat pumps have become a popular alternative to traditional heating, ventilation and cooling (HVAC) systems. They consist of many of the same parts as an air conditioning system. Heat pumps, however, feature a reversing valve as well. The reversing valve allows the heat pump to change or reverse the direction of the refrigerant so that it can produce heat. If you’re thinking about buying a heat pump, you may want to consider the following features.

#1) Zoning

If you have a large home with two or more floors, you may want to choose a heat pump with zoning. Known as a zoned heat pump, it will allow you to control the temperature of different spaces in your home independently of each other. You may want to set the ground floor to 70 degrees Fahrenheit, for instance, and the second floor to 73 degrees Fahrenheit.

#2) Auxiliary Heat

Auxiliary heat is a useful feature to look for when choosing a heat pump. As the name suggests, auxiliary heat is backup heat. If it’s particularly cold outside, the heat pump will use a secondary source to generate heat. Auxiliary heat typically consists of strips that are electrically heated.

#3) Scroll Compressor

Like air conditioning systems, all heat pumps require a compressor. This cooling component is designed to compress the refrigerant. While most heat pumps and air conditioning systems use a reciprocating compressor, some of them use a scroll compressor. Scroll compressors feature two scrolls, one of which spins around the other, stationary scroll. Scroll compressors are quieter and better protected from premature wear and tear than reciprocating compressors.

#4) Desuperheater

Some heat pumps have a desuperheater. It’s a secondary heat exchanger that’s used to heat water. Heat pumps produce heat when operating in cooling mode. Normally, this heat is released outside. Heat pumps with a desuperheater, though, recycle this heat. They’ll pull heat from inside your home, and they’ll use this heat to create hot water. With a desuperheater, a heat pump can save you money on water heating expenses.

#5) Variable-Speed Blower

You may want to choose a heat pump with a variable-speed blower. Variable-speed blowers are highly energy efficient. When the heat pump initially turns on, the blower will operate at a slow speed. It will gradually speed up until it meets your heating or cooling demand. There are also fixed-speed blowers. Fixed-speed blowers operate at a single speed. They can’t speed up, nor can they can slow down.