[radtek]

I instinctively closed all the vents in the rooms I don't use last year but then opened them up when I read somewhere that this was bad for the duct-work. This duct work needs a little TLC so I'm afraid to put too much strain on it- but am I correct? I've been cooling areas of my house that are never used.

rad

 

[beenthere]

Not the best thing for an A/C or heat pump.

Leave them at least 1/2 way open.

 

[radtek]

They've been wide open for at least a year. I keep the doors of the rooms open too.

So I guess open is best!

 

[beenthere]

Yes.

Its easier on the whole system.

 

[sweaty]

Seal your ducts with foil tape on every seam and hole. Remove the register covers and seal the gap between the ducts and the drywall, especially on the returns. You'll get more of the conditioned air that you're paying for to go where you'll feel it.

 

[radtek]

Should I seal any gaps with expanding foam or regular caulk?

I could seal with the expanding on the outside of the ducts (in the attic) and either still use it inside or just use some DAP silicon.

 

[sweaty]

Seal metal ducts with the foil tape. After you've done that, I would bury attic ducts with insulation. Heavily insulate the rest of the attic, as well. It's a job you do once and it saves you money forever.

 

[radtek]

I have another question-

In these rooms I have turned the ceiling fans on high even though they aren't used. The doors remain open and they are at the end of fairly short hallway (8').

At the opposite end of the hallway is the return for the AC.

I understand that "air" doesn't like to turn corners... However, would it be better to leave the fans off in the rooms so the "cold" air can flow out the doors and along the floor's surface towards the return?

Or possibly have smallfans blowing the air out of the rooms?

Possibly a little more efficient?

 

[beenthere]

If the rooms aren't used.

I'd turn the fans off. The fans are normally used to prevent stratification. Don't really need to worry about that in rooms that aren't used. So you save a few dollars by not running those fans.

Doubt it will make any difference in how easy the air makes it to the return. Cooler air going to the return may or may not help the system.