We have a heat pump and emergency heat. Other than that, I know very little about heating or AC systems. Everything seemed fine except for the fact that I noticed at night the fan rarely switched off. Then we got our energy bill in and we had used more than 4 times the normal amount of energy last month. I knew something was wrong and recorded our energy use for several days. During the time our heater was on and set to 70 degrees, we averaged using 168 kWh per day vs. 13 if the entire heating system was turned off (and this is to heat an 1800 sq ft. home). While I realize that it of course takes energy to heat a home, something seems very off. So I started trying to figure out the cause.

After paying close attention. I've noticed that our heater will warm our home (warm air comes from the vents) until the thermostat reaches about 67 degrees. The air continues to blow, but it is no longer warm at that point. This is with the thermostat set to warm to 70 degrees. I think it will eventually get to 70 degrees, but it takes hours. I left the heater running (the house was 63 degrees) this morning for close to an hour and a half and the temperature never got above 67 degrees and began blowing cool air. It will heat to 67 degrees within the first 20 min or so and then level out and never get any warmer. And if it is relevant, our home is only around 10 years old, so the heater would not be any older than that.

Anyone know what could be causing this? I will likely have a repairman out to look at the AC/Heating unit, but I want to be informed before I do so that I don't end up spending unnecessary amounts of money. And of course, if it is a simple fix (such as an issue with programming), I'd like to attempt to fix it ourselves. I'd at least like to have an idea as to what the problem is, though. Thanks!