Does the temperature of the air entering the return directly affect the supply temperature on a heat pump system?
I'm asking because the finished room above our garage has the return (only 1) outside the room. Outside the room is a foyer and stairs, and there's only 1supply register in this space. It supposed to be conditioned space, but it's always very cold this time of year. I have to keep the room door closed all the time. The solid wood door is undercut for the return air. The VisionPro thermostat is located inside the room.
Just wondering if the return should have been in the fully conditioned room and what affect it's having on heating/cooling the room. Based on how cold the foyer/stairs is, I would like to have an insulated exterior door that is weatherstripped, but I know I can't block the return air exiting this room. Or can I?
Thanks for your suggestions.