Install cold air return.

[mscher]

Our very old two story farm house (with newer heart/air), does not have a cold air return up stairs. Basically the upstairs is a bedroom and bath (both with 1 heat duct each) and a hallway in between.

If I cut a hole in the hallway wall and the floor sill, there is a straight shot down between the studs, down to the basement, where the main air return is.

For attempting building code purposes, what would be the requirements, to create this return? whould there need to be duct or sheet metal between the studs, or could the area simply be sealed?

 

[NSBCraig]

Re: Install cold air return.

Not sure but you probably have to duct it one way or the other to prevent a chimney in case of fire.

 

[Bob_VT]

Re: Install cold air return.

I take it that you have forced hot air......

Is there a CAR in the first floor? Is there an open stairway to upstairs w/o a door?


I have an older farmhouse too. My main CAR is on the first floor and goes directly to the furnace. As far as the second floor goes the stairway provides plenty of "draft".

The individual vents in the rooms need a place for the air to return for efficiency.... It depends on how close the bottom of the door is to the floor to allow the cold air to flow out.

As far as the vent goes to the basement you mentioned it would all depend on your local codes. I do know a key thing is to hook it to the furnace.... on a side note of caution..... that is a direct attack at the second floor in the event of a fire and would ingite everything enroute if it is not lined.

 

[WizeOne]

Re: Install cold air return.

My house was code built in 1986 and the returns just run between the ceiling and floor, in between two floor joists, with no special ducting. So I assume thatwould not be an issue.

As far as clear passage up your wall, between studs, I don't think anyone could know for sure if their are no fireblocks in them. I would assume that older homes did not have them.

Being an old farm house, it probably has the old wood lath strips and plaster. I don't think that stud finders work very well on that type of construction.

I guess fireblocks are not even required today, in the National Building Code specs. I think that certain locals do require them however.

 

[mscher]

Re: Install cold air return.

I take it that you have forced hot air......

Is there a CAR in the first floor? Is there an open stairway to upstairs w/o a door?


I have an older farmhouse too. My main CAR is on the first floor and goes directly to the furnace. As far as the second floor goes the stairway provides plenty of "draft".

The individual vents in the rooms need a place for the air to return for efficiency.... It depends on how close the bottom of the door is to the floor to allow the cold air to flow out.

As far as the vent goes to the basement you mentioned it would all depend on your local codes. I do know a key thing is to hook it to the furnace.... on a side note of caution..... that is a direct attack at the second floor in the event of a fire and would ingite everything enroute if it is not lined.

There is a CAR on the main floor and the stairway is opened. Is the starway considered the CAR?

The main reason for this effort is the I get very little heat/cool flow from the bedroom duct. I thought about putting a booster fan on the duct, but wanted to make sure everything else is up to snuff ( as well as a country house could be)

 

[Bob_VT]

Re: Install cold air return.

If the bedroom is not sealed off you should get flow. Yes the stairway will work as a CAR or just a simple vent between the floor and the cieling below.

In every vent in the basement that comes out of the furnace there is a flap valve ..... it took a bit of adjustment but you just might have to balance the flow the way you like. You pop open a duct and install the "valve by drilling two holes.

I also insulated a few of my ducts that carry hot air the furthest distance (horizontal) away from the furnace to retain the heat.

 

[SS MAYFLOAT]

Re: Install cold air return.

Hot air rises and will force the cold air down the steps unless the doors are kept shut to those rooms. If they are kept shut, the blower can only blow in air to fill the room. Once it is full, it will increase flow back into unrestricted vents and stop flow to those upstairs rooms.

If you put a CAR in the hall in the upstairs, it may help, but you still may have problems if those doors are shut. You still need to have a way for the air to flow out of those rooms into the hall to find its way down the stairs.