andre 12,000 BTUs= 1 ton for a three ton system, you want both 36,000 BTUs in both cooling and heating. many HPs depending on brand, mdl, system configuration shortchange the homeowner on the heating side and sometimes both. how can you tell? check the AHRI HP Directory. and I would recommend anyone considering any new HVAC system to wait and see the standards to qualify for the tax credit which reportedly will be included in the expected Federal Govt stimulus package. Don't you love how our government spends taxpayer money? and as I recall from your past threads, you should request a load calc because I suspect a 2 1/2 ton is borderline undersized for you and the extra 1/2 ton would certainly help you on your heating costs. ryan is steering you in the right direction. I have the XL14i(R-410a) dual fuel system and while it is a nice HP, I would have gotten the XL15i but it had not been introduced at the time of my install some four yrs ago. IMO

It was also an additional $1,100 to go from heat pump to gas downstairs. wait a minute. the comparism isn't apples to apples. starting at a base 13 seer ac with electric strip to 13 seer ac with gas furnace...this is xxx cost 13 seer with elec strip to 13 seer heat pump is xxx cost. this is the baseline. gas furnaces cost more than elec strip heat in equipment costs. heat pump cost more than ac elec strip. then the seer upgrades come in to play. with the gm of the company, start with baseline prices to get understandable, fair cost comparisms. if you get off on the right foot...with both being fair & open with each other, the process may improve. make sure that you provide information specific to your house with house plans. while plans have window sizes & orientation, there is a world of difference between a double pane metal window & a double pane low e argon filled vinyl window. things like solar heat gain coefficients & ufactors of windows should be provided. sizes of overhangs, any exterior shading. air infiltration in your home should be less than normal houses if you have done your air sealing. the foam at the roofline contributes to this air leakage reduction. so instead of house being entered into load calc program as average or normal, the entry instead would be tight. so provide information above and beyond what is spec'd on plans and that is accurate as to what you bought & had installed. R-values of insulation & types of insulation. the devil is in the details...and these entries make a load calc that is specific to what you built instead of equal to the spec house down the street. best of luck. (you are doing great btw)

Persimmon Yes, this can be accomplished. First your location. And then the mdl number of your HP. Size of your home? You will need the best matching evap coil for your application along with a correctly sized furnace. Since you already have AmStd HP, I recommend you stay with this brand. And finally, you will probably need new Dual Fuel thermostat with an outdoor sensor. I do suggest a good box filter cabinet if you don't have one already. IMO

Swithcing from oil to gas, especially when the gas line is already in the house, is an very easy decision. You will easily cut your heating bills in half. I recommend you have the plumber install a separate gas hot water. The hot water heater can be sized to your needs. Usually 40-50 gallons is adequate for most families. This is also a more efficient to heat hot water resulting in additional savings.