A condenser that only cools is called a “straight cool” unit, and there are several ways to tell the difference between a heat pump and straight cool condenser. Probably the easiest method is to check near the bottom of the data plate on the side of the condenser for the words “HEAT PUMP,” or “CENTRAL COOLING AIR CONDITIONER“ or “CONDENSING UNIT” for straight cool air conditioners.

    A second way to figure it out is to Google manufacturer’s name and the model number from the data plate, which will usually tell you what type of unit you have, as shown below. Both these methods assume that your data plate is still intact and readable, which is sometimes not the case for an older machine.

    If the data plate is no longer legible, you can look through the top grille into the center of the condenser for a horizontal brass tube, like the one shown below. It’s the reversing valve, which switches the direction of refrigerant flow to to change from cooling to heating, and will only be seen in a heat pump. Usually, the reversing valve is readily visible, but some manufacturers conceal it behind an access panel. So the presence of a reversing valve indicates that you definitely have a heat pump but, if you don’t see one, it doesn’t automatically mean the unit is a cooling condenser. Onward to a fourth strategy.

     Put the thermostat at “HEAT” and raise the setting ten degrees above the current room temperature. Make sure it is not set at “EHEAT” or “EMER HEAT.” Then, after you feel heat coming out of the registers (vents), go outside and see if the condenser if running. There may be a few minutes time delay for the system to turn on. When you have a heat pump, it will be operating and blowing cold air. If silent, then you have a cooling air conditioner with a heat strip in the air handler. 

    Also, see our blog post What is the canister thing about size of a small soda can on a refrigerant line near the heat pump or air conditioner condenser (outdoor unit)?

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  To learn more about heating and air conditioning systems, see these other blog posts:

• How can I find out the SEER of my air conditioner? 

• My air conditioner won't turn on. What's wrong? 

• How can I find out the size of my air conditioner? 

• How can I tell whether the condenser (outdoor unit) is an air conditioner or heat pump? 

• Where is the air filter for my central air conditioner and furnace? I can’t find it? 

• Does an old air conditioner use more electricity as it ages? 

• How did homes stay cool in Florida before air conditioning? 

• What is wrong with an air conditioner when the air flow out of the vents is low?

• Why has the thermostat screen gone blank? 

• Why does it take so long to cool a house when an air conditioner has been off for a while? 

   Visit our HEATING AND AIR CONDITIONING page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.