Backlit Thermostat Problem

Scott586

New 2.5T Carrier heat pump installed 6 months ago and has a Carrier Performance Programmable edge thermostat. Problem is the house gets cold, but the thermostat says it's 70F. If I turn the fan on manually the air circulates and after 3 minutes the thermostat reading drops and the heat pump kicks on. Often when I do this, the thermostat reading will drop down 6F or more and initiate the emergency heat. This can't be efficient. The temperature here in Illinois has been very mild, with outside temperatures at 50F or above, so it's not because it's too cold outside for the heat pump to operate efficiently.

I think I've discovered the problem. I think the backlit display is generating it's own heat and skewing the temperature reading. The thermostat is warming itself by this display backlighting. I have temporarily disabled the backlighting to see if things improve. I searched but didn't see any discussions regarding this. Has anyone else experienced this? For a supposed high-tech thermostat, this seems like a very poor design issue. If this is what's going on, surely I'm not the only one to experience this.

beenthere

Is the hole in the wall sealed?

joecaption

Any I've seen use an led lamp that puts out almost no heat.