I have a 1950’s split level Colonial(?), with HVAC Hot & AC system. I’ll be adding on a 2 car garage with an attached 12×12 room and 2, 2nd floor bedrooms. I had planned on a radiant heat system in accessable joist space and baseboards in the existing slab room. There would be 2 Spacepak systems, one for each floor. For quick heat the Spacepak would have hydronic coils.

Contractors I’ve spoken to insist that I keep the existing duct work, extend it, get a variable speed furnace and duct dampers to regulate the floors.Excerpts from some discussions: hot air is more efficient than hot water heat. That radiant systems are to slow to heat-up and that they run all the time to keep the water flowing, therefore less efficient than Hot air systems. That dry throats are caused by any system. I’ll need 2 boilers, one for the radiant, and one for the baseboard system. Spacepak leaks and is noiser than the other HI-V system.
Why change….
My furnace is on its’ last legs. The present duct work causes the ceiling in the basement to drop to 6′ 1″ in a 5′ X 18′ area. There’s lowered ceiling height in the slab area, where the duct runs to go upstairs, a 8′ X 12′ area.The 2nd floor never gets hot or cold enough. I’d like to eliminate the chimney to forgo a $1k repair. It will be easier to run pex than duct and I could heat my new garage slab. I’ll eventually save money on my Natural GAS heat because radiant is more efficient.
Have I spoken to the wrong contractors or am I missing something??
What is the forum opinion?
THANKS