AC and Radiant

John Jr

O.K has anybody had any problems with AC ducts dumping cold air into rooms. I have had this happen in two houses now. They dump cold air from the return and supply ducts. I have owners cover with plastic and they can’t believe the difference in room temp. What have others done with this problem.

John Jr

JudeNY

I close the supply vents and put the return filter in a white plastic garbage bag which cannot be seen. Yes, it makes a big difference.

Mark J Strawcutter

usually worse on first floor

Assuming attic AHU installation. Hot air rises to second floor and continues rising up thru 2nd floor supply/return ducts. Cools off in attic and falls down to first floor and out supply/returns there. Nice convection loop :-)

My SpacePak system has winter insert plugs for the supplies and I cut a piece of white foamboard (posterboard) the size of the filter for the return.

Previous house I just cranked the supply grille dampers closed and didn't do anything to the return.

Mark

BRUCE AVERY

Worse this year than most

Being in Maine we have a lot of hydronic heated houses that add A/C after the fact. In most cases we have just recommended that customers close the supplies as was suggested. This year we have had three houses with radiant not only sense the cold air, but actually have condensation dripping out of a couple of supply diffusers. We had them close the supplies then we ended up purchasing some vinyl sheet magnet that we cut to fit the return grilles. We only install mechanical air cleaners so the plastic bag trick on the return filter grille was not an option. The only problem is that some of our return grilles are aluminum, no solution there yet. Manufacturer's recommendation is to leave the fan in the "on" position or add electric heaters (with electric rates at $.1225 per KW that's not an option. If you hear of an other answers, especially on aluminum grilles I'd love to hear it!

Justin Gavin

just a thought

As mentioned close the supply vents or plug the high velocity holes and on the return grill cut a piece of scrap reflective bubblewrap or insultarp and tape it tight to a piece 1/4 " plywood fit to the space. It might cost a little initially but put in your price at the beginning and you won't have any problems.

Good Luck
Justin

Dave_4

condenation in mini ducts

Has anyone tried using dust collection blast gates , as Rockler woodworking sells , for winter time shutoffs in the 2 inch high velocity air ducts? Install at second floor ceiling level of ducts that run through closets to first floor.
And why not terminate the 2nd floor flex ducts into a piece of plastic pipe about a foot long,that extends down through the insulation on the attic floor to the room below. Then it would be easy not just to cap the pipe at the bottom but also to push a rod of foam insulation all the way up.
I'm just weighing the idea of not having 18 ice cold tubes down into my house. [If I wanted that I would not have gone.en up and filled all the gaps in the attic floor this summer. What a job moving insulation.] joe w.