Finding a furnace small enough ~22,000btu/h
A 1,100 sf home in Seattle I am working on needs a new furnace. The gas line is in place, the metal ducts were all sealed and insulated to R-15 and the walls and floor were also insulated to R-13 and R-30. Depending upon how tight the envelope becomes in the last wave of air sealing, the home will require ~22,000 – 24,000 btu/h, given my calculations with Manual-J 8. Now the trick is to find a nice furnace to put in there. Project’s priorities for the furnace:
Sealed combustion condensing
AFUE of 90% or greater
Will accommodate a return-side fresh air intake or similar
Can anyone suggest a current line of furnace to accomplish this?
Current water heater is electric, but will probably need replacement in the next 5 years or so. Combined hydronic is theoretically possible, but finding the right contractor and design on this type of thing would be really important. Maybe that contractor is you.
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