What I need to know, exactly, is what the difference in operating costs is between a 13 SEER non-variable-speed unit and a 16 SEER variable-speed unit. The cost difference to us will be $7000 and I want to know how long it will take, or if we can ever, recoup that cost difference in the life of the equipment.

That info will need to be supplied by the contractor doing the work. He should have done a manual J for your structure and you actually need that to do the start of the calculations.

Cost difference has to use exacting calculations and the calculations will have to be done for the 13 SEER and then the 16 SEER. Then the two will be subtracted and the energy calculations saved will be shown. Then you will need to muitiply the energy calculations by the cost of the utilitys to get a final dollar savings.

All this information is local from your utility company since you will also need a basis for usage. This can be a long drawn out affair but I can tell you that the difference from a 13 to a 16 will never pay you back for the extra expense unless you are heating and cooling a gigantic building.

Below is a tip for you to use in selecting a contractor and BTW get at least two but better yet three different estimates for the work to be performed.

Unless you are very,very young and get a warranty saying the 16 seer equipment will last about 100 years you will never recoup that cost difference

Without seeing your utility costs, there is no way to be sure, but I suspect you will not recoup $7K in operational costs. I would however recommended quotes for 14 and 15 SEER units, since the 15 might qualify for the government rebate. Once you know what each SEER rating will cost you, you can find your sweat spot.

Thank you all for your kind answers! And NO, we are not young, but do expect to stay in this house a long time! I'm about ready to go for the 13, I think.

$7000 dollars in difference of cost? Is this quote from the same person? I would get other quotes. That seems like a huge difference in price? Are they offering any rebates from the manufacturer? The 16 if done right would qualify you for the tex credit.