Any Suggestions

R.Cronstruction

I am bidding on a job with a unique situation. I am rebuilding a 15 x 21' old addition, due to rot, no insulation, 6'6" ceilings etc. Anyway, the total house is 1120 SF, has very little heat, a small electric wall unit in the part i'm remodeling and a wood fireplace, and the customer would like to install a heating, and possibly A/C system. The house is built on stilts and at high tide water can be 6" from the bottom of the floor joists, and there is no attic space so any ducts would have to be outside the wall or on the roof and no room for a furnace inside so it would have to be outside, kind of rules out forced air system. If i went HWBB boiler would have to be outside.

I am leaning toward a Mitsubishi "Mr. Slim" because of the heat and cooling combination. Since heat is their primary concern are there any hi efficency electric wall units available, or natural gas wall units?

any other suggestions would be appreciated as well.

A.D. Const

As for heating I would recommend radiant heat, for AC maybe you'll be able to tie to existing or install the Mitsubishi (or fujitsu)mini-split you where talking about. I have not seen wall mounted gas mini-split. For radiant you don't need a boiler you can use a tempra tankless water heater or standard heater whatever is more convenient.