Loft space heating, a/c, balancing

Old 12-15-05, 03:08 PM
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Question Loft space heating, a/c, balancing

I hope this will be an interesting question. I have read a lot of this board and people seem so thoughtful and helpful:

My wife and I have lived for 2 years in condo unit in a converted 1820's mill in Rhode Island. It's a 5-story brick structure with 12' ceilings, lots of high windows, etc. In this environment, (16F this morning) we are pretty concerned about our heating! (And the summers can get hot, too).

Our heating system is central forced hot air and a/c.

The layout of the unit is a rectangle, with 3 rooms along the outside wall: a large living room, a study/guest room, and a bedroom in the corner of the building with two brick walls. These rooms all have full-height ceilings and ceiling fans.

Parallel to these rooms are a series of small rooms, all under a drop-ceiling, which acts as a small attic area. These are a closet, a kitchen, a bathroom, a washer/dryer area and another bathroom which has a brick wall and connects to the bedroom. There is a small hallway, also with a drop ceiling, which runs between these rooms and the full-height rooms.

The heating unit is above the drop ceiling, closest to the living room, and farthest from the bedroom. The ductwork is primarily rectangular sheet metal, with 10" flex leading to the room registers (pretty saggy, but not more than 8' for any room). The single return is in the ceiling of a penetration between the kitchen and the living room. It uses 24" x 24" filters and its duct is a large (20" diameter?) flex duct, which runs back and around to connect to the far side of the heating unit.

The warmest part of the house seems to be the "attic" space, unfortunately. Next is the living room. Finally, the bedroom is never as comfortable, summer or winter, as the living room. Hence, the question of balancing the vents.

All of the 12' rooms have the registers at the TOPS of the walls, at about 10'. This really isn't conducive to bringing the heat down, even with the ceiling fans. It would have been nice if the registers had been brought down near the floor to bring the climate control to where the people are! But it's pretty clear that the developers were in a rush to get their work done, and weren't that careful about a lot of details.

Actually, the coldest room has always been the bathroom off the bedroom, but today I patched a length of 6" flex into one of the bedroom ducts and put it through the drop ceiling of the bathroom. This has already seemed to help a lot!

I also adjusted the balance a little: I mostly closed one of the TWO registers for the living room, and pulled out some very dirty register filters in the bedroom. Now the bedroom seems more liveable, but the living room isn't as warm, and the heat has been running almost constantly (on auto) since then. (of course, it IS cold out!)

One of the problems has been all along that the system, both summer and winter, seems to be struggling to meet our demands on it, running constantly, costing a lot, but not doing a great job at climate control.

After all of this prologue, I do have some questions that I hope people here can help me with:

1) Should I add another return in the bedroom? My wife likes to sleep with the door closed, and I have a strong concern that the pressure in there is preventing the hot air from entering. For example, if I open the bedroom door a crack, there is a strong flow of air out into the hallway where the unit's only return is. If another return is called for, should I

a) Turn one of the two heating registers into a return register and just connect it to the main return? This would be nice because it would be easy. But would it restrict the amount of warm air too much?

b) Run a nice big duct down into the open closet in the bedroom? It would be easier to run it to about 5' because of an existing shelf, but I could bring it down by the floor if that would really be a benefit.

c) Do both, install a y-valve and change where the air is drawn from by the season.

d) Change one of the top heating ducts to a return duct, and run a new heating duct down the closet, but open a register out the other side... under the bed?

e) Just cut a hole in the ceiling tile in the closet, and another one in the existing return flex duct, and use the whole darn "attic" as the return, and maybe recover some of that warm air up there while I'm at it?

f) Would I need to put another filter on the register for the return?

2) I'm guessing insulation is in order for the uninsulated duct work up in that attic. It's pretty hard to negotiate around up there - cramped and using loose boards laid over the 2x4's, although it *seems* stable at least. I'm wondering if using a self-adhesive duct insulation like Therm-Well would be ok. I'm concerned about my ability to use the Reflectix "staple tab" stuff up there. I would of course foil-tape all of the leaks first. Would I need to worry about any condensation if I were to insulate? We've not had a problem with that, at least.

3) Is there a possiblility the furnace just isn't putting out hot enough air? Using a thermometer, I am measuring 90F coming out of the vent in the bedroom. It doesn't really feel too warm to the touch. I'm used to really hot forced hot water radiators, though, and I just don't know what I should be getting.

4) Do I need those little filters that sit in the registers? There's really no way to replace them, and I think they are getting blocked. As far as the filter in the return in the kitchen, that thing gets so plugged up with olive oil (we've been successfully doing Atkins for years!) that I should really change it more frequently than every month. I guess the kitchen was not a good location for the return!

5) Any other recommendations?

Thanks in advance for your advice!

Old 12-15-05, 05:15 PM
airman.1994's Avatar
Join Date: Dec 2005
Location: VA
Posts: 5,795
Received 8 Votes on 8 Posts
Man that's a lot!
1. Return should never be in the kitchen!
2. Filter in the register throw them out before you kill your unit!
3. If door is under-cut no return needed
4. 90f Hope this is a heat pump!
5. Attic should not be that warm (leaky supply duct)
6. Have an HVAC company inspect duct and size of System
7. Did I get them all
Old 12-15-05, 09:32 PM
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thanks for the quick reply! of course, more questions now!

I think you did hit them all...

Do you think I should move the main return out of the kitchen? How about if I make one of the bedroom supply ducts the return? I'm afraid to use one of the ones from the living room because the distance is too short to the furnace: less than 10'. I guess I could extend it around to connect to the original return...?

I don't think it is a heat pump, but how can I tell? I cannot even see the name on the device, as it is wedged in really out of the way. I guess it would behoove me to find out exactly what it is.

Supply duct IS really leaky. I plan to hit it with a roll(s) of aluminum tape. What about insulation? Is the sticky kind ok?

I had an HVAC company in to do an "annual check" as recommended by the building manager. They said it was "fine", but I didn't have this list of questions for them.

I guess undercutting the door to the bedroom would be the easiest step 1 for me to do... but now I'm more worried about moving that return. Perhaps I could move extend it to the laundry area -- that has louvered doors.

Any other thoughts... anyone? Before I do something major?

Thank you airman!

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