basement heating -- duct placement

[James Owens]

I'm refinishing a Canadian basement and I need to decide where to put the heating vent in each of two rooms. The simplest thing would be to set them in the ceiling. I plan to insulate the ceiling with R12 and then cover it with acoustical tile. I'm also putting a return vent at floor level in the opposite corner of the larger room (there's no easy way to run a return vent to the furnace from the small room).

Obviously the walls will be insulated. The floor is OSB on sleepers, open at one end to provide air flow (and I may cut some floor vents at the opposite end to improve the flow).

Will this be adequate, or is it advisable to run the heating ducts down the partition wall and place the outlet vents near floor level? This would require a "bump" near the ceiling in each room, to get the duct down from the joists and into the wall, so I wouldn't do it that way unless there were a significant advantage.

-- "For it is only of the new one grows tired. Of the old one never tires."

-- Kierkegaard, _Repetition_

James Owens, Ottawa, Canada

[Joseph Meehan]

Assuming you have a heated living space above and are going to heat the basement full time, why are you planning to insulate the ceiling?

Sorry I don't have an answer to your distribution questions. There is enough of a difference between your area and mine, I would only be guessing about distribution, but if it were me, I would try to get those ducts down to floor level.

[James Owens]

I thought if I put the ducts at ceiling level, the heat would dissipate upwards before it had a chance to warm the basement properly. The upstairs would be heated by the regular ductwork in part, but in part also by this rising heat. That would cause the thermostat to shut off the furnace sooner than if the upstairs were heated by ducts alone. (I'm assuming here that the heat loss by conduction through the floors would be significant -- maybe that's where I'm going wrong?)

The same would apply if the ducts were at floor level, but to a lesser degree since the air would have some time to dissipate its heat in the basement before it reached the ceiling. Therefore I was considering insulation mainly for the first option.

That was my thinking, but I am asking for other opinions.

OK, thanks.

-- "For it is only of the new one grows tired. Of the old one never tires."

-- Kierkegaard, _Repetition_

James Owens, Ottawa, Canada

[Jeff Prevett]

I saw a segment on TV dealing with heating a basement. It was on Just Ask Jon Eakes on HGTV Canada.

He said that the best way to heat the basement is to put the hot air vents in the ceiling and put the returns near the floor. The return pulls the cold air off of the basement floor, thus moving the warm air (from the top of the room) to the bottom of the room. It has to do with the preception of warmth. By indirectly heating the lower part of the room and pulling the cold air out of the room, your feet are not as cool and thus you feel warmer.

Now to add my input.

I agree with Jon. If you put the hot air vents on the floor, a few bad things might result. First, you mention having to build a sofit for the pipe. I find the less sofits, the better (visually and, well, it's easier to build). Second, if you have AC, you will have little air change in the basement while it's running. The cold air would enter the room at the bottom and stay along the floor and return to the furnace leaving the top of the room stale.

Jeff

[James Owens]

Did he say anything about insulating the ceiling? It s sounds like there would be no point, since the hot air is pulled down by the vacuum effect of the return air duct.

One of the rooms won't have a return air duct unless I go through some hoops to do it. I wonder if I should run a computer fan to pull the cold air into the storage room next door.

-- "For it is only of the new one grows tired. Of the old one never tires."

-- Kierkegaard, _Repetition_

James Owens, Ottawa, Canada

[Jeff Prevett]

I would not insulate the ceiling. There isn't any insulation between my 1st and 2nd floor. However, you might want to insulate to reduce noise (ie from say a home theatre in the basement). But you mentioned that you're using a suspended ceiling so the acoustic tiles will reduce the noise. Also, insulation in a suspended ceiling is not really a good idea; It will make it harder to do things above the ceiling in the future (one of the reasons people put suspended ceilings in basements in the first place).

It won't be a big problem, just leave the door open when not using the room. Try to then install the return near both rooms. The problem with using a computer fan is the extra cost to operate the fan as well as the noise. You mention a storage room. Maybe you can route the return through that room.

One last thought. Make sure that the area of the returns doesn't exceed the area of the hot air vents (i.e., if you have 3 hot air vents measuring

1"x10", make sure that the total returns are not bigger than 30 sq. in.) Better to have the returns a little smaller. This is because you could end up with backdrafting problems (with the furnace and hot water heater).

Jeff

[bambam]

I'm a contractor in Calgary. Usual practice is heating vents in the ceiling; cold air returns at floor level. (Cold air dropping moves out of the room, pulling warm air down.)

I recommend supplementary electric baseboard heat, thermostat controlled. Beats trying to balance hot air heat between two and even three levels. Also, good in the summer when the furnace is off.

No reason to insulate the ceiling, no reason to build a sub floor.

Ken

[Joseph Meehan]

You are kidding, right. Just incase you are not, a computer fan will not even begin to make a dent. Don't bother. You could try a bathroom vent fan, get a high volume, low noise one.

[James Owens]

Thanks. In my case the subfloor was required for levelling. I had to custom-rip the sleepers in short lengths; one of them works out to about

3" at one end and 0.5" at the other over about 11 feet (the worst case). Most of them average about 2", but in no case was I able to use a parallel cut.

-- "For it is only of the new one grows tired. Of the old one never tires."

-- Kierkegaard, _Repetition_

James Owens, Ottawa, Canada