Wolfgang

House was built in 1924 and has cold air returns throughout the first floor. Prior owner(s) decided to finish attic and ran Furn/AC duct to it. No cold air returns though. Colder than rest of house in winter, and in the summer have to use a window AC unit and open a window with a small exhaust fan to keep it cool.

I was thinking of putting in an inline (in duct) auxillary fan to push more air up there but am stumped on what to do about the return. Is there a way to have a passive type cold air return to vent to the crawl space or outside? I really dont want to have to run duct through the ceiling and first floor to the basement if I dont have to.

HVAC_Ryan

Seems simple but has the door been undercut? Back in the day before returns to every room they did this. Cold air migrated to floor, under door and back down to R/A. How big of a room are we talking?
Personally I'd steer clear of additional penetrations in such and old house. Even with a back draft damper there is infiltration.

__________________
"They must find it difficult...Those who have taken authority as the truth, rather than truth as the authority." - Gerald Massey

MetalBender

I owned a Craftsman home from 1922 and had the same problem. Right or wrong here's what I did. Insulated duct up through old chimney, no longer in use, with a booster wired in to furnace in basement. This fed two 12x16 rooms through the north wall. For a return I used two 3" PVC pipes cut into approx. 24" pieces and spliced together in side of chimney one by one, twice, for two 3" returns. Both returns I then ran under floor to bathroom on the south, and opened the floor. Used OEM gravity cover from house. Another heat duct and plumbing for bathroom came up from a pocket door cavity below also. Like I said, right or wrong, but it worked well.

Wolfgang

I think I might try going with a louvered door at the bottom of the steps going upstairs. I really dont want to cut into anymore ceilings and floors. If it doesnt work, than on to plan B...which I have no idea what it is at this time.

flashheatingand

The lack of return may be a contributing problem during the summer months, but I wouldn't think it's the reason that the attic is the coldest part of the house now. I would think that you aren't getting enough supply air & the t-stat location are the major factors. But, as an experiment, you might just leave the door to the area in question open 24/7 to see if that helps with the heating situation (or take it off temporarily). If so, then go with the louvered door.

Just a thought

Dr Heat

heat rises if it is cold upstairs maybe you need more insulation. Opening the door will rule out the need for a return.