I recently installed a 2 stage heat pump inline with my Trane propane furnace. I was able to set the system working correctly with my 3rd gen nest thermostat using the pro setup and setting the system for dual fuel.
My gripe is this is they way Next handles dual fuel is very simplistic. The only way to bring on the propane furnace is if the outside temperature drops below the break over temperature set by the thermostat. My 15 year old Honeywell thermostat lets me specify time to temperature letting the system kick on the gas furnace if the house hasn’t hit temperature in a user defined interval (I set mine for 60 minutes). Only using the break over temperature doesn’t work a lot of the time. If the requested temperature rise and/or the outside temperature is too low, the heat pump will never hit the requested temperature without turning off and turning on the gas furnace.
As a feature request I would ask that as a minimum, Nest dual fuel has a time to temp setting. Better yet the Nest should do something similar to heat pump balance available with electric aux heat and use AI to learn which combinations of temp rise and outside temp will need gas heat to achieve.
Sorry, just my rant. I really like the Nest with it’s combination of features, Ui and integration with other Google products but if this dual fuel issue isn’t’ resolved I’ll have to switch to an Ecobee.
Cheers, Gordon
