Radiant floor or ceiling in remodel?

GroundUp

The time has come. The better half has put her foot down and said we're either getting a new house or remodeling this one. I really don't care as I don't spend any time in the house anyway, but I'd rather not move all my tools/toys/guy stuff/etc and abandon everything I built here. We have a 40x40 detached with a 21x40 lean and radiant slab heat I built 8 years ago as an auto/welding shop and parking as there is no attached garage. Last year I built a 32.5x48 detached with a 12x32 lean and radiant slab heat for toy storage and a shop for my hydronic heating business. If we remodel, I'm going to add an attached garage as well (thinking 30x36) to get our vehicles out of my shop and that will also have a radiant slab. It would be attached on the walkout side of the house so I'm debating adding living space above the garage as well, which would obviously require heat/cooling too.

As it sits now, the house is 1400 sq ft with full walkout basement. Built in 1996 but essentially a doublewide without axles so just a 2x6 framed rectangle. Forced air heating/cooling aside from some underfloor in 2 rooms because the ductwork is butchered up and there's not enough airflow to that end of the house. I'm thinking if we do this remodel, I'll gut the whole house to the subfloor and start over with a blank canvas, including the heating and cooling system. I'd love to do a gyp overpour system but the load bearing is going to be an issue as well as the height. I would rather not be raising doors and messing around with the exterior too. As it sits now, my vision is an entirely new HVAC system with a 3 ton air source HP and LP backup- mostly for cooling but some light heating duty as well, and a complete overlay of the existing subfloor with warmboard or make my own with ripped 3/4" plywood and omega plates. Finished floor would be LVP throughout the house. I have enough height to get away with that if I play the cards right, but my sensible side says radiant ceilings with the same method are a better option. I hate overhead work, but it seems to me the comfort level would be superior and more likely to meet the design or recovery load as water temp can be raised higher. Main heat source is an outdoor wood boiler but the radiant slabs have electric boilers for backup and the proposed radiant in the house/attached garage would likely be the same, possibly an LP mod/con.

I know you probably didn't need most of that info, but I sure hate when someone asks for help and has no supporting information so I just gave you everything I could think of.

Jamie Hall

The thing which would concern me is -- can you get enough heat out of the floor, if you go that route? If your double wide is anything like the mobile home I once had the insulation leaves something to be desired, and I wonder about your heat loss.

Radiant ceilings are... OK... my father-in-law's house had them in some of the rooms. For my taste they sort of gave the illusion of being warm enough, but the floors stayed mighty chilly.

Panel radiators?

GroundUp

Jamie Hall said:

The thing which would concern me is -- can you get enough heat out of the floor, if you go that route? If your double wide is anything like the mobile home I once had the insulation leaves something to be desired, and I wonder about your heat loss.

Radiant ceilings are... OK... my father-in-law's house had them in some of the rooms. For my taste they sort of gave the illusion of being warm enough, but the floors stayed mighty chilly.

Panel radiators?

Yes, I can get enough out of the floor for design temp but it gets 20 degrees colder than design a few days a year and I would use the forced air as supplemental heat regardless of the primary. It's not a doublewide, but built like one. 2x6 walls with fiberglass batts, R48 roof, and the CMU basement has 3" of spray foam on the inside for an R21. Design heat loss at -20F is ~37,000 including the basement.

I have installed a few radiant ceilings and have been pleasantly surprised, but admittedly have not spent any amount of time in the homes to determine just how nice they are though I have heard nothing but praise from those customers. Being the floors are wood with heated space below, I don't foresee cold floors as an issue.

Panel rads are an absolute no.

hot_rod

I have retro fitted both floor and ceiling in the 1950 vintage home was had. I'm sure you know to get the structure as efficient as possible first, load calc on the upgrades home.
Do your design with maximum SWT at 120, or lower if you can. then you should be able to work within an A2WHP throughout the heating season. LP back up for HP break downs.

The idronics below was put together specifically for the purpose of low SWT systems, with upcoming low SWT heat generators.

Of the two systems I would still do floors over ceilings when possible. With ceiling radiant I could still notice cold areas under furniture, at the dining table, etc.
Heated floors are a must in bathrooms.

Or, no reason to not go hybrid, ceilings would be nice in sleeping areas, really not a lot of time spent walking around bedrooms:), The bed and furniture covers most of the floor anyways. Radiant ceilings are fast responding, so a light setback could be used for the bedrooms with ceiling radiant.

Living and bathing spaces I prefer floor heat.

https://www.caleffi.com/sites/default/files/file/idronics_25_na.pdf