Home>Discussions>INSULATION & HVAC>cold first floor bedroom—where to locate a cold air return?
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cold first floor bedroom—where to locate a cold air return?

I have a first floor bedroom that was an older 1950's-60 addition to the main circa 1920 house. It has a poured crawl space underneath that is open to the main basement through an old basement window opening approximately 30 inches square. The room is 13'-6" x 11' and has one heat vent in the wall near a corner. Heat source is an older gas forced air system. Currently there is no cold air return in this room. The heat register is about 30' from the furnace. The main duct work is rectangular and has two short 90° branches just before it enters the crawl space under the bedroom and runs parallel to the south wall just a few feet in from the wall. The current register for the room is close to the southwest corner. Should I relocate it in the floor closer to the end of the main duct? And where should a cold air return be located relative to the heat register?

Any thoughts are much appreciated as it is really cold back there.

Re: cold first floor bedroom—where to locate a cold air return?

You could try installing a better quality supply grill. Some better grills (commercial style) can flow up to 30% more air, without changing the size. You could also increase the register size.

IF you have a central return now, a return won't make that much difference as long as the door to that room is undercut adequately to allow air out when it's shut. IF you have returns in the other rooms now, just locate the return wherever its' easiest. Location is't that critical, but it should be on the opposite end of the room.

Another way to improve comfort is to balance the system. IS there a room that's warmer than the rest? IF so, you could install a simple butterfly damper on that branch, and reduce flow to that room. Reducing airflow to one room will increase flow to the others. Repeat adding dampers and reducing flow until all room heat up eveenly.

Re: cold first floor bedroom—where to locate a cold air return?

The return should be closer to the inside wall opposite the supply if possible. Because heat rises it's better to put a heat return on the floor to pull back the colder air at floor level. If you have a cased coil instead of an air handler for A/C then the floor should be fine for both heat and A/C. Most retros that use an air handler are in the attic and returns and supplies go in the ceiling. If you have an air handler be sure to close the return and supply off during the winter so not to lose any heat. With this being said a lot has to do with the way the house is laid out,(floorplan). The closer to the main the better but I wouldn't expect to much of a difference as 30 feet is far but not unreasonable. Another return and that room should have 2 six inch supplies or 1 seven inch supply

Re: cold first floor bedroom—where to locate a cold air return?

Yep -- ditto Sten's post.
Also , the ducting that runs to that room should be checked for leaks and sealed. If that crawl space is not well insulated then the duct work could also benifit from bieng wrapped with insulation.

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