heat pump, central air and heat and a mini split as far as cost of operation? heat pump same as central air and heat except that the heat pump provides the bulk of the heat. this is what I recomend to my clients based on savings compared to electric strip heat. with heat pumps the electric strip is emergency heat and for when temps are 30 degrees..which is not that often for us. central air is electric strip heating only. the most expensive way to heat your home. (espically if you have entergy for your utility provider) mini splits are pretty cool. expensive but fit a lot of needs and great for tight retrofit spots. the condensing unit goes outside like with any set up, but this is where it changes. in each room the air is provided by a wall mounted air handler unit. the condensing units are up to 3 tons. each room would have the ahu..this is what they are calling zones. cost is higher, but you don't have ductwork, so it evens out a little better. with the foam insulation & low e windows your tonnage of ac required will be less. although I don't recomend 'rule of thumb' sizing instead of the ususal 400 to 500 sq ft per ton, your house will be more in the range of 600 to 700 sq ft per ton. oversizing will cost more to operate, wear the equipment out sooner, and will NOT dehumidify. be diligent in finding out what is being spec'd for your home and what options are available for you. some systems will qualify for tax credit, and it is always a good idea to do better than the legal minimum allowed by law (code). in what part of La. are you building? best of luck.

How much extra are you being quoted? Right off the cuff I'd say I would go for the heat aspect as it would give you greater control over marginal heating needs and spring and fall, and might need some heat in the early morning or late evening, but cooling during the day.

What kind of water heater do you have? If your boiler is more efficient than your water heater, you might consider moving your hot water source to an indirect tank fired by your boiler.. I think that you missed my point about heating performance of mini splits in cold climates. Some models retain their performance to a much lower outdoor temp than others. One example are the Mitsubishi Hyper Heat models. The ones you have your eyes on may not do as well, but I don't know for sure because I am not familiar with Pioneer. Yes, unless your gas-fired heat is horribly inefficient, there is no way you should be able to heat with resistance heat or heat pumps for less coin. I think that you need to check your calculations. I just looked up that 1 therm equals 29 kWh. I assume that is 100% of the energy in the therm. With your boiler, we have to guess at an efficiency. If we say 80% you get 23 kWh out of a therm. That says that for the same amount of heat, you pay 5.35 cents in gas vs 10.1 cents for electricity. (Frankly, I am surprised that the difference is not greater. Maybe I made a mistake.) As I wrote previously, there may be some savings in spot heating with electric spot heaters, but not heating most of the home that way. You'd have to cut your heat loss by partially heating the home to nearly half. For a heat pump at those fuel costs, it might be worthwhile. If your window units keep you comfortable enough, you will likely be happy with the cooling performance of mini splits. The good ones are good at humidity control, but you need to have variable speed compressors and blowers for that. They do entail considerably more maintenance than a central air system. For heating, you just have to crunch some numbers to see if they are better than your hydronic system. Keep in mind that raw fuel (electricity) efficiency is only one factor. Lifetime costs of the equipment should be factored in as well. A bunch of mini splits is a lot more complex a system than a simple boiler and a circulator pump.

I am thinking out loud a bit here but: you might consider a ceiling fan. In heating season, set to draw air up, at low speed (and possibly adjusting where the minisplits direct the warm air). The idea is cool air is drawn up, forcing warmer air down outside walls, and more consistent temperature throughout, including less feeling of radiant cool from cold surfaces. Can't say how much it would help in terms of comfort but I can say this for sure - would be a lot less expensive up-front cost and easily reversible if you don't like or can always just leave it. To me would be worth trying for a hundred or two bucks. A lot less than hydronic baseboard. (It won't directly lower heating costs but if you are uncomfortable at a given temperature, it's likely you're setting temperature point above what would be needed if more even throughout)