Technical Article #2 - Identifying Heat Pumps

At first glance, it can be difficult to differentiate heat pumps from air conditioners, especially during the summer months. The following are some of the ways to tell.

Look at the data plate. It may say Heat Pump on it, or the model number may start with HP. If it does not, you can jot down the manufacturer’s name and model number and contact the manufacturer.

1. If the thermostat has an Emergency Heat setting, you can be sure it’s a heat pump.
2. If you take the cover off the thermostat (beyond the Standards) and find that it’s a two- stage thermostat, this indicates a heat pump. (You must know what you’re looking at here.)
3. If both Freon lines are insulated, it’s a heat pump.
4. If you open the condenser cabinet and find a reversing valve, it’s a heat pump.
5. If you find two expansion devices with bypasses, it’s a heat pump.
6. If the compressor is indoors and it’s an air to air system, it is a heat pump.
7. If there is an outdoor thermostat connected to the control wiring, it’s probably a heat pump.
8. If it’s winter and the unit is operating, it’s a heat pump.

Is It Still Being Used As A Heat Pump?

In many northern climates, heat pumps were often installed with the encouragement of local utilities. For various reasons, they were found to be unsatisfactory. Many have been disconnected and are used only as air conditioners. You won’t be able to determine this visually, but your client may want to ask the current owner whether the heat pump is still used for heating. In many cases, it is cheaper to have the “back-up heat” supply all of the heating, especially if the back up is a high efficiency gas furnace. Where the available back-up heat is electricity, heat pumps are more cost effective and more likely to be in service, even in colder climates.

If you’re looking at the house in the winter, and the system is operating on the Emergency Heat setting, chances are the heat pump is not operative.

<< Back to Main Page