I have an Earthlink system in MIchigan and it works perfect. My suggestion to the customer with high electric use
first find out if Temperature diference across the coil multiply that by CFM and Multiply that by 1.08 The answer is the amount of btu's the coil is giving you in heating mode, or removing in the cooling mode.
Mine is 23TD X 1900cfm X 1.08 =47,196 btu's
If the performance is good. Check the Amp draw with a clamp on amp meter. A4 ton should draw 16- 17 amps. Mine draws 14.1-14.5 amps.
Multiply Voltage by the Amperage that will give you wattage. 14.5 X 240 =3480 divide by 1000 = 3.48KW X 6 and a half cents/KWH = aproximatly 23 cents and hour to run.