Interesting that your installer says in floor heat is more expensive than hvac. I've loosely considered in floor heat but basically give it a pass because of the work involved. My house is open concept, rectangular shape and vaulted ceiling down the length - with a second floor "hallway" between the bedrooms is open on the one side that looks down onto the first floor. across the one side of the second floor are bedrooms, the other side as I said is vaulted ceiling coming up from the first floor - if you can picture that. Because it's so open my wood stove at one end of the house can heat the whole house with almost no difference in temp from one end to the other. (with the aide of 3 ceiling fans although normally I only run one fan.) The whole main floor is flagstone. But no underfloor heating. In my laundry room I actually had to lift up the flagstone when I did a renovation there - and found I could get them up without too much difficulty. But the thought of doing the whole house and putting in underfloor heating is not something I think I will go thru with unless I win the lottery! But I've always thought if I could heat that floor that would be the perfect heating solution. (Hence my surprise that your installer thinks hvac is cheaper to run than in floor. but maybe it's based on house design.)
These discussions always have a lot of perception involved. Perception of what's acceptable in regards to cost, efficiency, comfort, etc.
For example, my previous house had a thermostat in each room. The entire house was always the perfect temperature for the particular room you were in. The house temperature ranged 5F degrees. That was by design and personal perception.
Your house heats with wood with, according to your perception, "no difference in temp from one end to the other". I might walk thru your house and think differently because of my perception. Your perception might change slightly if you used a temp indicator and checked the temp of a piece of furniture in the same room as the wood stove, then checked a piece of furniture in the lowest, farthest room from the stove.
Our house temp varies 3F degrees with our floor heat, no zones, one thermostat centrally located. My perception is we have a large variance in temps. That perception is based on coming from a house that I could control in each individual room. Now the variance is out of my control and is noticeable. If I was to ever do another floor heat house it would be zoned. My current house should have 3 zones to get that ideal "perception" of proper heat in each area.
In regards to operational costs. Again, it's all about perception. I believe my HVAC guy. I am 100% sure I can heat my house cheaper with the air to air exchanger 90% of the time. I.e., temps above 10F degrees. I am 75% sure the propane fired high efficiency furnace will heat the house cheaper with temps below that 10F degree mark.
But, as he said, that won't make my floors warm. It is impossible for me to explain the feeling of radiant floor heat. The colder it is outside the warmer it feels in the house. It's equally comfortable regardless of what you are doing, standing, sitting, laying in bed, standing naked in the bathroom after a shower. It's that way because everything you touch is the same temperature. It's not colder over by the exterior wall. Your head isn't warmer than your feet. That is not obtainable with any type of forced air heat, including a wood stove.
Because you can't flip a switch and get instant satisfaction from floor heat it requires some pre-planning. An adjustment of the thermostat will take at least 24hrs to be truly reflected in your perception of warmth/coolness in the house. That has been the hardest thing to get used to. I was accustomed to instant satisfaction.
Best part of radiant floor heat is the non-invasiveness of it. In day to day use you never know it's there. No air blowing around. No noise. No dust/dirt. No vents to keep exposed. No strategic placement of furniture to get the best heat result. You can utilize every square foot of floor space.
I think it would be extremely hard to add hydronic floor heat to a house. But people do. So house design would come into play. We knew we were using it when we built. We are on a concrete slab.
I cut wood for 40 years. I never minded doing it. Now I never miss it and wouldn't even consider going back to it. Burning wood is not cheap and when compared to modern heating devices is rarely efficient.
