Correct lockout on Dual Fuel Trane
Two years ago I purchased a dual fuel Trane system. I have a XC95 45K btu 3 stage communicating gas furnace and a X15i heat pump. The system seems to work well enough for the past two years. We didnÂt actually save in cash on the heat because we started using more heat. For the longest time we kept the house heat on 60 degrees in the winter. Now we keep the heat on 68 and the bill is just slightly lower than it was with the old system. Air conditioning is hard to compare because we havenÂt been home and there havenÂt been as many days that I need the AC running.
I assume by getting dual fuel, I would be able to adjust the system to take advantage of which ever form of heat was cheaper. For the longest time electric was cheaper so I thought I should lean a little more on electric heat instead of the 1st state gas heat. I kept the lock out on 40 degrees. That was really a guess because the dealer couldnÂt show me a formula to set the optimum lock out temperature.
Well in January 2011, electric rates are going up 20% in Pennsylvania. IÂm trying to figure out if I will need to adjust my lock out on the heat pump. Running the 1st stage gas when there is just a call for "a little heat" has to be competitive to the cost of running 20% more expensive electric.
Since the dealer couldnÂt help me, I tried calling Trane direct, they were zero help. Can anyone tell me if such a formula exists to help me set the temperature correctly?