Air Handler and ductwork in attic for upstairs heat and AC?
We have an 1800sq-ft two-story home in Boston area built in 1929, with single pipe steam heat, run off oil-fired boiler that is 40 years old and inefficient. We plan to switch to natural gas, install new high efficiency boiler and indirect hot water heater. our hvac man says he can rework first-floor radiators for forced hot water and add return lines, but very hard to get return lines from upstairs radiators without tearing house apart. Since we also want AC upstairs, he proposes installing an air handler in the unfinished attic with a heat coil (hydro air unit), and running a hot water pipe from new boiler up to attic to provide forced hot air heat via new ductwork in attic to and from the four upstairs rooms through ceiling vents. He will also tie this air handler to a new AC unit to be installed alongside house, to provide upstairs cooling in summer through that same ductwork.
So we would have a hybrid system, with forced hot water radiators on first floor and in finished basement, and forced hot air on second floor, both running off the same new HE boiler. And we would get AC in the process. (We have just done blown-in cellulose insulation in walls, and air-sealing, so house is pretty tight). This HVAC plan makes sense to me as a layman.
My major concern is the proposed ductwork in an unconditioned attic that gets mighty hot and mighty cold. We have a good vented roof. Is this system okay if insulated and sealed well? How much energy loss? Any alternatives?
Thanks for guidance!
Last edited by smithglobe; 07-08-2012 at 02:56 PM.
Reason: (fixed typos in headline and text)
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