RocMark,
I also live in Fairport and just had a 24k gal. IG pool installed. I faced the same question because I'd like to take advantage of fpt electric, but I ultimately decided to go with gas. The main reason being is that my backyard faces south and is in the sun all day, so my heating needs are limited to early and late season and an occasional mid season boost if we have some cool weather.
Also with gas, I can allow the water to cool down (not run the heater at all) and then, for example, on the weekend I can run the gas heater and boost the temp by 1+ degrees per hour. I don’t think you can do that with a heat pump, so you must leave it on (I think).
Two of my next door neighbors also have pools and they don't run their gas heaters much at all. If our pool wasn’t in the sun all day, I think the decision might have leaned much more to a heat pump.
By far the biggest benefit for reducing heating costs (and chemical use) is to use a pool cover. Make sure it’s on the pool at least every night! If you don’t use a pool cover, the payback on the heatpump is a lot quicker.
I used the charts at the links below, in addition my neighbor’s experiences, to help me arrive at my conclusion. Based on this, I figured it might take 7+ years to break even on the heatpump, and that wasn't worth it for me.
Hope this helps and good luck!
Heat pump
http://www.eere.energy.gov/consumer/.../mytopic=13220
Gas
http://www.eere.energy.gov/consumer/.../mytopic=13180
about solar covers
http://www.eere.energy.gov/consumer/.../mytopic=13140
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