Placement of supply registers in basement

**Raymond Wand** · 11-17-2010, 08:07 AM

Looking for any research or other articles which would substantiate placement of supply registers at basement floor level rather than at the ceiling level.

Thank you.

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**Bruce Ramsey** · 11-17-2010, 03:37 PM

To some degree it might matter what season you have more of.

Here in the South we don't worry about heating. We only care about air conditioning. We only have temps below 40 F for about 30-45 days a year. Registers on the floor spewing air conditioning are poor designs.

Most of the basements in the South are walk out basements with only one wall fully below grade. We have different mositure concerns as a result.

Up in the frozen north where you bury you basements and spend 4-6 months heating, ceiling mounted registers probably makes more sense.

David Bell · 11-17-2010, 05:31 PM

The register cfm and throw is more important here. Just like on any other floor of the house the object for heating is to "wash" the outside wall with heat. The flow pattern should be strong enough to create a tumbling effect of the air, providing an even feel in the space.

**Markus Keller** · 11-17-2010, 06:59 PM

Sorry, don't recall reading anything in Manual D that addresses that. Running along the floor in the basement .. would mean they are running a trunk inside the wall along the floor? I'd be concerned about contamination in the event of any water seepage into the basement. Also the trunk could act as a good raceway for rodents. I'd also want the trunk line insulated so the metal isn't in direct contact with the concrete. Placement of furniture blocking air flow could also be an issue.

**Raymond Wand** · 11-17-2010, 07:41 PM

I should clarify that the supply registers would be approx. 12" above the floor and not in the floor but located on the wall.

**Garry Sorrells** · 11-18-2010, 12:48 PM

Look to system design concepts for air circulation at varying temp and density.
Look for books that are for the teaching of HVAC trade.
The key is book, n. ot online. Book will have more in-dept information.
Put in a call to your local trade school.

**Rod Butler** · 11-18-2010, 02:13 PM

Ontario? Locate the registers near the floor in the basement just like you would on the main level.

Also locate your returns at floor level as well to pick up the coldest air to return to the furnace.

**Robert Hronek** · 11-27-2010, 05:17 PM

The placement of registers is to compensate for air leaks and low insulation levels. In a tight, well insualted house there is not the need to bring vents to the outside walls.

I tight, well insulated home will not have the cold spots that require strong mixing strategies. If you are in the planning stages go for a tight well insulated home. Seal the sill plate and rim joist with spray foam. Shoving a piece of fiberglass up there is basically useless, no air stopping potential and doesn't really insulate.

For a warm basement floor insulate with 4" or more of rigid foam. A thermo-mass wall with 4" of rigid insulation inside the poured concrete acts as the insulation and a capillary break.

I like ceiling vents as they are not blocked by furniture. With a tight, well insulated house the air will not stratify like it will in a home that is poorly built.

**Ken Amelin** · 11-27-2010, 07:58 PM

Originally Posted by Raymond Wand

Looking for any research or other articles which would substantiate placement of supply registers at basement floor level rather than at the ceiling level.

The location of the register can be where you want it to be as long as it is designed properly. Supply air quantity is determined by the heat loss. Registers are selected to distribute that air quantity bases on throw and velocity. They can be located where ever you want them to be.

**Rod Butler** · 11-29-2010, 08:12 AM

Originally Posted by Ken Amelin

The location of the register can be where you want it to be as long as it is designed properly. Supply air quantity is determined by the heat loss. Registers are selected to distribute that air quantity bases on throw and velocity. They can be located where ever you want them to be.

At the risk of beating a dead horse . . .

Of course registers can be placed wherever you want but to improve comfort they should be place at the location of the greatest heat loss/gain; at the outside wall near windows. (The best external glazing still loses 12 times the amount of heat per SF than that of a very well insulated wall.)

Placing registers on inside walls and blowing to the outside wall is great for cooling but in a heating application it can be a major mistake. The idea is to eliminate drafts.

And a tight well insulated home will stratify and is compounded if the furnace selection is incorrect or inefficient.