Before I start out, here are the specs on the equipment:

Heat Pump: Lennox 13HPD-048-230-01 (4 ton)
Air Handler: Lennox C33-49C-2F-3
Furnace: Lennox G43UF-60C-110-8 (92.1% AFUE)

Performance chart (closest I could find -- everything as listed above, but uses G60HV-60C-110 instead of my G43UF):

F____C____kW in___kBtuh out___kW out
65___18___3.28______57.0_______16.7
60___16___3.26______54.3_______15.9
55___13___3.23______51.6_______15.1
50___10___3.20______48.8_______14.3
47___8____3.19______47.2_______13.8
45___7____3.13______44.5_______13.0
40___4____2.99______37.7_______11.0
35___2____2.84______30.8_______9.0
30___-1___2.90______30.8_______9.0
25___-4___2.95______30.9_______9.1
20___-7___3.00______30.9_______9.1
17___-8___3.03______30.9_______9.1
15___-9___3.02______29.8_______8.7
10___-12__3.00______27.1_______7.9
5____-15__2.80______24.1_______7.1
0____-18__2.60______21.2_______6.2
-5___-21__2.41______18.2_______5.3
-10__-23__2.21______15.2_______4.5
-15__-26__2.02______12.2_______3.6
-20__-29__1.82______9.3________2.7


Cost of natural gas is $0.52 per therm
Cost of electricity is $0.13 per kWh

I've tried to figure out a realistic economic balance point for the system (it's a 4 year old house that I bought recently). Living in the Kansas City, MO area. From what I can figure out, it will cost me more to use the heat pump than to just use gas. I've read so many stories about heat pump efficiency and setting balance points that I have difficulty believing that gas will cost me less than the heat pump.

During the past summer, the air conditioner was able to keep it 76 degrees F inside on all but a couple of 102+ degree days, when it got up as high as 78 degrees F inside. We've had 20 days of 100+ degrees, so the system seemed to do okay (wallet didn't do as well).

The original owners had the Lennox Merit 51M32 thermostat balance point set to 55 degrees F. All of the stories I've read talk about setting balance point to anywhere between 15-30 degrees F.

Can you guys figure out if I should just leave the balance point at 55 degrees, or does it need to be set lower?