I recently purchased a vacation home that has two thermostats for a forced hot air gas furnace and a separate A/C unit that shares ductwork. The A/C also cools better when both the A/C and furnace fan are running.

I’d like to consolidate thermostats but don’t want the A/C fan running when the heat is on.

I was thinking about wiring the A/C fan connection to the compressor connection on the thermostat. That way the fan and compressor would run along with the furnace fan when the A/C is on but when the heat is on, only the furnace fan would run.

Does anyone see any issues with wiring it this way?

  • How are the air handlers and plenums/main ducts configured? Commented Jun 25, 2019 at 1:26
  • So you want to replace the two thermostats with one single thermostat? Sounds like a workable plan. A thermostat will often cut off the compressor and let the fan run for another minute or so to run air over the coils. With the fan and compressor jumpered, that won't happen, depending on how the blowers are arranged.
    – JPhi1618
    Commented Jun 25, 2019 at 16:05


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.