Is my Lennox XP-21 heat pump operating efficiently?
I live in SE PA and recently had a Lennox XP-21 heatpump installed with electric strips for backup heat. I received my first full month's electric bill and it was a bit higher than I expected (2100 kWh - last year before the HP it was 899 kWh) so I am wondering if there are any obvious things I should check to ensure that the HP is running efficiently.
For example, is there a way to determine if the electric backup strips are being used too much (if at all)? How can I know if the HP is running in the 1st stage or 2nd stage?
I have the thermostat set at 67 during the day and 65 at night. Is it more energy efficient if I leave it at the same temp all the time? I've received conflicting information about the setback two contractors and there seems to be two schools of thought in these forums.
The outside temperatures have been ranging from the mid-30s to upper 40s and the compressor seems to be only running a couple minutes at a time several times an hour. Also, I've never seen my thermostat indicate that the Aux Heat is running (but I'm confused if the Aux heat on the thermostat means that the strips are on or if it means that the compressor is running in the second stage).
(PS Please forgive any technical misstatements in my question - I'm a homeowner who is very interested in understanding how my HP works - not a Pro!)