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What Parts Make a Heat Pump Different From an AC?

You know that heat pumps and central air conditioners are different, but they also work very similarly, too. So what’s the difference between the two systems anyway? There are a few key components that set a heat pump apart from more traditional central air conditioners. 

You can keep reading to learn more about how heat pumps are different from other air conditioners. Then, give our team a call when you need to schedule service because of any heat pump problems. We are always here to help, even if you just need questions answered.

How a Heat Pump Works

Most central air conditioners do not also offer heating. Instead, they have separate heaters that are also attached to the same thermostat. When you change the thermostat settings from heating to cooling or vice versa, your thermostat turns off one system and turns the other one on.

But a heat pump works differently because it has a reversing valve. When you change your thermostat settings, your thermostat triggers this reversing valve to change the direction of refrigerant to either heat or cool your home. A heat pump is most well known for its reversing valve, although there are other components that help contribute to how it operates.

Additional Expansion Valve

All air conditioners that use refrigerant for cooling have one expansion valve. However, a heat pump has an additional expansion valve that helps to lower the pressure in the refrigerant when the refrigerant lines get reversed. This additional valve basically adds extra power so that your heat pump can change directions more effectively.


Your heat pump also has a defroster to prevent ice from building up on the outdoor unit during the colder months of the year. It’s a problem that you don’t have to worry as much about when you have a traditional air conditioner, because it isn’t operating when it is cold outside. But, with a heat pump, cooled refrigerant is cycling outside to absorb heat and bring it back inside.

Sometimes this cool refrigerant can encourage ice to develop on the outdoor coil. The defroster has a sensor that alerts the heat pump system when the outdoor unit gets too cold and then triggers for heat transfer through the refrigerant as a way of increasing the temperature to melt any ice buildup. 

Suction Accumulator 

Another unique component that central air conditioners do not have is a suction accumulator. Since the refrigerant reverses and moves in the opposite direction in a heat pump, it has a greater risk of entering the air compressor. If even just a little bit of refrigerant mixes with the oil inside of the compressor (an occurrence called slugging), it can cause problems for the whole unit. 

The suction accumulator helps to prevent this from happening. If any refrigerant begins to enter the air compressor, the suction accumulator traps the refrigerant before it can mix in with the oil. It is essentially a failsafe to prevent problems that are unique to a heat pump. 

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