Learn which mode you're currently using, and go from there.
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:
- 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.
- If turning on the heat doesn’t make your outside unit run, you’ll probably hear sound coming from your basement, a closet, or the ceiling when your heat is on. This would mean you have a conventional system.
- Check out the labels on your condenser or indoor air handler for a model number or name. You likely can search this up to figure out what type of system you have.
