Originally Posted By: Fitter30
has the equipment cooled and heated the house to your satisfaction over the years, if your going to be in your house for more that 5 years, if you have good thermpane windows and good attic insulation I would pick the same size equipment at a 15seer as unit. if your gas furnace is a standing pilot unit you have to look at the btu output not input to size the furance.its on the nameplate by the burner. furnace, ac coil, condenser and freon lines have to be change.
15 SEER??!? That's awful lousy in my world. I love split ductless systems. Inlaws have multiple of them in their home (the lack of ducting makes installs much more straightforward in their type of hurricane-proof Caribbean home). Ive installed SD units in my home now as well, and theyre absolutely wonderful and quiet. Getting rid of the ducting has major ramifications on system design, operation, and efficiency/losses.
In a 1000 sf home, a decent sized SD may be all that is necessary for AC.
Then the heating system could be optimized (do they make mod/con units for forced air?), and the system would be much higher efficiency.
SD may not be viable based upon home layout, etc. But its sort of a matter of what parts are on the out, and what is the best solution to resolve. Ive seen plenty of homes with multiple HVAC systems to support the overall home (often an upstairs and downstairs unit, for example), as well as homes that use hydronic with forced air AC or split AC. I suspect hydronic with split AC is actually the highest possible efficiency, which is why I went that way in our home.