Cold Bedrooms

[Mikeyboy]

I have a forced air system and I had guests sleep over this past weekend and when they shut the bedroom doors on the 2nd floor at night, their bedrooms got really cold. The reason is because there are no cold air returns in the bedrooms. My cold return is on the low side on the 1st floor and high above on the 2nd floor.

What can I do prevent the rooms from getting so cold when the door is shut. I know I can cut the bottom of the door so air can pass but I wanted to see if there were better solutions than than.

Do those louvers work when I can put a hole through the wall to allow air to come out of the rooms?

[Marc46]

Yes,.........you can cut a pass-through return above the door, and cover with stamped face louvers on both sides.

Another option is to do a cross-over return, which is in the ceiling.
You simply install a grille box on both sides of the door, and connect the 2 boxes together with flex duct.

You must have very tight fitting doors!

[Mikeyboy]

I want to remove cold air so whatever I do needs to be on the low side.

I do not have space about the door to cut anything. I could only install a vent on the low side of the door but cutting into the door.

Is it better to install a vent on the low side of the door or undercut the door? Which is better to remove more cold air out of a room when the door is shut?

Would installing a vent on both sides of a wall help remove cold air out when the door is closed?

[leejosepho]

Is it better to install a vent on the low side of the door or undercut the door? Which is better to remove more cold air out of a room when the door is shut?

Would installing a vent on both sides of a wall help remove cold air out when the door is closed?

The only way to actually *remove* cold air from a room is to pull it out mechanically, and that is usually done with a cold-air return. Short doors and/or vented doors and/or vents through the walls can offer a path for air to flow, but no air is actually going to pass through such an area unless or until there is first either an absolute flow of air *into* a room to force it out or an actual draw in the hallway to pull it out. More than likely, your forced-air flow into a room is not an "absolute" than cannot be easily restricted, and neither is your hallway an effective cold-air return. So, you are probably going to end up having to install either cold-air returns or powered vents somewhere along the bedroom walls.

[Mikeyboy]

On the 2nd floor, I have a return on the high side of my master bedroom and on the ceiling in the 2nd floor hallway. I have one other high cold return on the 1st floor. I also have a cold return on the low side underneath the stairs on the 1st floor too.

During the winter, I completely cover both high returns on the 2nd floor because it seems to suck all the warm air back into the return instead of keeping it on the 2nd floor.

Since the only returns in use during the winter are the ones on the 1st floor, will installing Short doors and/or vented doors and/or vents through the walls help pull enough cold air out of the bedrooms on the 2nd floor when the doors are closed.

If so, which is the best method?

[leejosepho]

Since the only returns in use during the winter are the ones on the 1st floor, will installing Short doors and/or vented doors and/or vents through the walls help pull enough cold air out of the bedrooms on the 2nd floor when the doors are closed.

If so, which is the best method?

Short doors or vented doors would only be passive and would not make much difference unless the cold air in the rooms is actually being pulled by some other part of the overall system, and they would certainly not be as effective as leaving the doors open altogether. Powered vents in the walls would definitely actually *pull* air from those same rooms, but the overall effect would still be dependent upon some other part of the overall system actually pulling the air farther along and back to the furnace. One end of my living room tends to be cold, and I use a powered vent to address that problem. However, I do not know what would be best in your case.

[Mikeyboy]

What do you mean by powered vent? Is this one of those vent boosters to pull more heat out of the ductwork? Or is this a standalone thing that you connect to a wall to pull cold air out of a room? Or one you connect to your roof? Where can I get this powered vent?

[jadnashua]

One thing that will help is to turn the fan on and run it all the time. It's less obtrusive with a multi-speed fan since it wouldn't be at max speed (and it save money - a good reason to opt for the variable speed fan on an air handler/furnace).

either shortening the doors (note, especially if it is a hollow core, there are limits on how short, or you'll not have anything holding the door skins on the bottom!) or putting in a vent to allow air to be pulled out of the room should help. The existing return will pull some air out of the rooms. Note, though, that if your return ducts were sized for all three of your mentioned ducts to be connected, shutting off two of them could be starving your furnace and shortening the life of the fan assembly while decreasing the overall ability of it to blow air out. Restricted air in means less air out...while using more energy trying to do its job.

[Mikeyboy]

Then what can I do to keep warm air in the 2nd floor instead of it getting sucked into the high returns on the 2nd floor?

Has anyone used a wall fan to install in between a room wall and hallway so air can be pulled out when the door is closed? If I undercut the door or install vents in the door, privacy becomes an issue with sound.

[Ian Gills]

This sounds like a tall tale. Have you checked the attic insulation above that room?

All the cold areas in my house (when the doors were shut) were due to a lack of adequate insulation in the attic, especially on those areas with more than one external wall.

I have yet to insulate my kitchen. I am too big to get through the access area for that room in the attic and need to persuade the wife to go instead.

[leejosepho]

Restricted air in means less air out...while using more energy trying to do its job.

Oops! A restricted fan or pump motor draws less power, not more ... and that is why the rpm increase when a sweeper is plugged up!

[leejosepho]

What do you mean by powered vent? Is this one of those vent boosters to pull more heat out of the ductwork? Or is this a standalone thing that you connect to a wall to pull cold air out of a room? Or one you connect to your roof? Where can I get this powered vent?

I just did a search for "room ventilator", and this is the first link that popped up:
http://www.tjernlund.com/retail/aireshare.htm?gclid=CPPC66jQ-JcCFSMeDQodYGcCCg

[jadnashua]

Running the fan continuously helps. That heated air at the ceiling gets pushed/pulled back through the system and comes out the (hopefully) lower vents, preventing stratification, filtering the air better, and evening out the temperatures. Try it for a day or two, as it is as easy as flipping the switch on the thermostat control. Otherwise, you have no other choices but to add vents. You could add them in the floor, but that would take more work. You could offset them into a room below, but it would transmit noise more. There are ducts made up of insulated panels (not metal) that would limit that, but not prevent it. You might need to check with the inspector on the local fire codes first, though.

You could put booster in-line fans to force air into those rooms (you might get some whistles as it escapes though restricted gaps).