New build tri-level; 861 sq ft top, 2068 middle and 1950 lower (half exposed) Looking at heat pumps on all three or radiant in floor lower with tankless water heat (electric or gas???) Thoughts on radiant with tankless??? Too expensive for middle floor radiant so must stay with heat pump. Western NC temps. Other suggestions for heat/air....heat pumps vs furnace. Tankless vs hot water heater?

Tankless heaters are very efficient and fairly expensive. Be sure to use a good quality water treatment system in order to keep the heater from scaling up. I don't know where in western NC you are, but I am near Clay county and the water here is quite hard and "lively". Copper piping does not hold up well here.
Radiant heat has been around for over fifty years, and is enjoying a come back recently. It has always been a wonderful method to provide quiet comfort, but it too is fairly expensive. Be sure to get several references for whom ever you may hire. An improperly insulated slab,a design or piping problem at the outset would be nearly if not completely impossible to overcome later. Using a seperate tankless heater to heat the water in the radiant loop sounds like a great idea if you can keep the outlet temperature set low enough. Thermal shock to the boiler (yankless heater in this case) should not be an issue.
Heat pumps in my opinion are ideal for this part of the country. Please do yourself a favor and insist that your builder use an HVAC contractor that handles good quality equipment. It takes the same amount of labor to install good equipment as it does bargain brand.
Your electric utility should be able to help you with specific information and any rebates or incentives available on heat pumps, water heaters, appliances, or any other energy star rated products. Good Luck!

Thanks Gary.....our water is a bit hard, inline filter handles most. HVAC guys suggested 2 ton top floor, 3.5 middle and 1.5 for half buried lower level. Still thinking OF 5 ton middle to handle air conditioning for lower if I go the radiant heat. Grew up in the 60's and 70's with infloor radiant heat under slate....IT WAS FANTASTIC, which is why I am looking now.....if affordable. Any thoughts on propane fired tankless vs electric?

five tons for the middle may be to large. Remember your not only cooling but removing the humidity as well. If the unit runs and cools to fast, the humidity will not be removed and you will find yourself unconfortable even though the room is cool. Also the benifit of having smaller units is the energy savings as the smaller they are the more efficent the system when running.
Depening on what area of the country you live in gas can be more or less expensive then electrical methods of heat. Also remember if the power goes out no heat at all with electrical while depending on the system you installed you may still get some heat out of a gas unit though convetive heating of the water.

Thanks for the comment on the larger unit. Have ruled that out as I know long term would not be happy. Will have gas logs for when power goes out (Ice storms every year here). Direct vent or ventless??? Looks like going with three smaller units is the plan. Had suggestion today to install pex in floor and add radiant when budget allows.

The direct vent works the best as far as efficency. Also allows you to place it anywhere you can get the gas to.
Just be real sure you clean the catilitic converter before you turn it on. It will produce a large amount of CO as it burns off the dust.
The Pex idea is a good one if you can afford it.

Thanks again. I read where most articles state the ventless burns the hotest and does not need to have glass doors closed all the time. Not concerned about oxygen depletion as room is very large, 17' tall ceilings and loft opening from above and open stairway on opposite side of loft. Apparently ongoing debate on ifficiency.

Why worry about efficiency when you have 17-foot ceilings? I guess you LIKE paying utility bills.

But you ought to see the view!! Only one room, opened above to second floor, great window wall south and west, gas fireplace in center which will then heat upstairs.