Not sure if the HVAC system at a property is a heat pump or a traditional furnace setup? This quick reference guide walks you through a few key ways to tell the difference. While a visual inspection or operating test can usually provide a strong clue, it’s important to know what you’re looking for—and what common misconceptions to avoid. Use this step-by-step process when evaluating a system during an inspection.
1. CHECK FOR A REVERSING VALVE
Look inside the outdoor unit (preferably when it’s off) to see if there’s a reversing valve, typically a horizontal brass component with several lines connected. This is the most reliable way to confirm a heat pump, though it can be tricky if you’re unfamiliar with HVAC components.
2. LOOK AT THE THERMOSTAT
If the thermostat includes settings like Aux Heat or Emergency Heat, it’s likely a heat pump. However, thermostats can be incorrectly installed, so don’t rely solely on this method.
3. OPERATE THE SYSTEM(WHEN IT’S BELOW 65°F)
- Turn off the thermostat and wait 2–3 minutes
- Switch to heating mode (not Aux or Emergency) and raise the set temperature by 1–2°F
- Step outside and listen. If the outdoor fan turns on, you’re likely dealing with a heat pump
4. WATCH OUT FOR COMMON MISCONCEPTIONS
- The outdoor unit is a compressor, not automatically a heat pump. This gets confused often.
- A home can have both a heat pump and a gas furnace. Some setups use gas as backup heat.
- When in doubt, describe the system as “forced warm air” to avoid making incorrect assumptions.
