A little background info... I am getting ready to replace my HVAC system with a heat pump and 90% propane furnace for backup.

I finally heard back from the natural gas company and since the only NG appliance I will have is the furnace, they are going to charge $500 to run the line and set the meter.

Being that the furnace will only be used in a backup capacity, any guesses on how long it would take to recoup that $500 bucks? Home is in Winston-Salem, NC. I don't know how much propane I have used the past couple of years. I have a 500 gallon tank, and I don't know how much is left from one season to the next, so that makes it hard to know how much I use per season. Past usage won't be of much help now anyway since I will be using the heat pump for the majority of heat. (I hope.)

The current rates are $2.80 per gallon for propane and 1.70 per therm for NG.

Thanks.
Bill M.