Try New York thermal. They are located in Canada and have many distributors in the NE. They have150 K btu propane “condensing” boilers that hang on the wall. I have one that heats 7000 Sq foot house with radiant tubes under the floor. The exhaust is just vapor and is relatively cool.
My son has one of the boiler system that works extremely well with radiators.
No pilot light. Works well with the balancing of the OATvs temp in house.
Very efficient!
Recommend this brand highly. Others out there as well. Look up “condensing “ heaters.
My son tells me that my pevert exbrother in law has one and wants me to look at it, I’ll take a pass I can’t stand the poof.
This seems to be an Ideal solution to my problem because I only need freeze protection and back up for my pellet stoves. The main thing is reliabilty I don’t want to go to FLA and come back to a frozen house.
Thanks for the pointer.
Bill