I want to swap out the old air handler for a new one and the old straight AC for a heat pump. I will not be putting a heat package in; I will use my boiler as the emergency heat.
The boiler is in the basement and only feeding baseboards. No hydronic coil up at the air handling unit. I only have the evaporating coil that comes in the unit to work with the heat pump. I’m not sure what kind of boiler it is.
Is this possible with any 1 cool 2 heat thermostats?
Separate wires are run already and I do have the right amount of conductors to switch to a heat pump instead of straight AC.
Best Answer
I'm currently running such a setup with an Aprilaire 8620W thermostat. AC from the heat pump, Heat from the heat pump when outside temp is >=40F, Emergency Heat from the boiler kicks in when outside temp is <40F.
The thermostat initially installed was a Honeywell model, and that could be configured to support AC, or could be configured to support Heat, but could not be configured to support both. It took about 18 months for the contractor to figure that out (because it only became an issue at season cutovers, e.g. spring and fall; they'd fix it to whatever season was appropriate and leave without realizing the other season had been broken). I believe the model was VisionPRO 8000 Wifi.