Heat Pump Lockout in South Central, PA

[busterbrown885]

I have a Bryant 355CAV Natural Gas Furnace
Bryant 288A Evolution Heat Pump, 18.2 SEER and 9.5 HSPF
My electric cost is 7.55 per kWh
My natural gas cost is .6999 per Ccf

I live in South Central Penna and am wondering if someone might provide me with a rather simple way or a suggestion on what I should set my Evolution thermostat heat pump lock out temperature at?

The thermostat is set at 69degrees during the day and 60 degress at night time and I allow about 1/2 hour or so for the heat to rise in the morning. While comfort is certainly a concern I am wanting to be mindful of the cost and would guess at some point the cost of natural gas and efficience of the furnace would be less expensive than the heat pump. Suggestions on what that temperature might be?

Thank you

[SJProwler]

First off I'd get rid of that setback, it has to be costing you more than you are saving, keep it no more than 5 degrees and most guys here will tell you to have NO setback with a Heat Pump.

For fuel comparison see the following

http://www.warmair.com/html/fuel_cost_comparisons.htm

[beenthere]

At those rates. The gas furnace(if its 95% efficient) is probably cheaper any time the outdoor temp is below 40.