Quote:
Originally Posted by MN Renovator
In the southern US, usually square footage is more expensive, typically homes don't have basements(which is where we normally put ducts and furnaces in the North), and people down there building houses don't think the public wants an air handler or furnace in a closet near the kitchen(noisy near the bedrooms or living rooms). There's more to it than that but if I had to move to the South for some reason and bought a house with ductwork in the attic, I'd seal up the attic, insulate the attic, and seal all the ductwork(so the air inside the ducts can't touch the air in the house). I'd likely remove it rather than just close it off though because insulating and sealing the attic would be easier. In the southern US I'd want the most cooling efficiency I can get and the winter isn't that cold so both of these coins add up to a mini-split setup. ..just don't forget to deal with solar gains through windows. I'd still do R60 in the attic, even down there, that way I don't have to care how hot the attic is.
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I've never understood this either. Our house had two heat pumps, 2 ton each. The main floor system had the air handler and all ducts in the attic. It blew 120F air for a minute at the beginning of each cycle. The condensate pan was primordial soup. Virtually all of them I've looked at eventually plugged up and overflowed condensate into the ceiling.
I replaced both units with window shakers during the remodel. The summer electric bill dropped by half so I never got around to installing a new heat pump.
Another odd thing is the regional preference for black asphalt shingles. I put a light colored metal roof over mine with a convective air gap. Also cut a 4 inch wide opening along the ridge, screened it, and covered with a ventilating cap. My summer attic temperatures dropped 30 to 40 degrees. A sealed attic is definitely a bad idea here. 150F is normal in a Georgia attic.
The new (single) air handler is going in the basement. All but two ducts are out of the attic. Those are heavily insulated and I may still block them off if the system performs as expected.
I am installing hydronic for primary heat to take advantage of the lower delta T. The air handler will be primarily for air purification in the winter.
I now have 38 windows in my house (about 15 before the remodel). The summer heat gain with premium windows isn't that bad.