Sub-floor radiant heating or baseboard radiators for 500 ft 3rd floor apt?
I just bought a home that needs new heat on the top floor apartment. It is small 1 bedroom about 500 S.F. I am looking for best way to heat the place with city gas available at the meter. I like the gas fired wall hanging heaters that I have a place for and get good gov't incentives. I found one (triangle) that also has dom. hot water (DHW) in one boiler. Can I use this with pex lines on the baseboard to supply heaters in bedroom, Kitchen/dining, living, and bathroom rooms? But today I was just reading about warmboard and similar items that would run pex on the floor to heat whole house. Can I do this in bathroom under tile and under laminate floating floor? I read it only uses 90degF water so it operates boiler at best efficiency.
Lastly, is this overkill since there is a second floor apartment below the floor that is heated separately? I could probably get away with elecreic space heaters given the small space, but how do I calculate the cost differences?