Some thermostats have both “Conventional” and “Heat Pump” modes, causing them to have two lines of terminal labels. Your system is only using one of these two modes. All you have to do is figure out which mode is currently in use and then use that set of labels for the compatibility checker.
If you don’t know what system that you have off-hand, no worries! Here are a few dead giveaways:
1. Try turning on the heat, then check if your outside condenser/air conditioning unit starts running. If it does, you have a heat pump system.2. If turning on the heat doesn’t make your outside unit run, you’ll probably hear sounds coming from your basement, closet, or the ceiling when your heat is on. This would mean you have a conventional system.3. Check out the labels on your condenser or indoor air handler for a model number or name. You can likely search this up to figure out what type of system you have.4. Check your HVAC control board for the wire labels. The control board will most likely have only one set of labels which corresponds to either a heat pump or conventional unit.