Why is House Drafty

Stacey lives in a nice house that was built the same year I was born! It's in Winnipeg, Manitoba Canada where it can get bitter cold. Let Stacey tell you what the problem is:

"Hi. I'm in a 1,100 square foot one and one-half story house built in 1952.

During the colder months I feel a draft even when the heat is cranked. The furnace has been checked and works fine.

I've put plastic on my windows and caulked window seals.

I think I have too many or incorrectly placed cold air returns. My hydro bills are $300 +/- and it seems like I am heating my house more than I need to.

All vents are on the wall just above the floor except for the one floor vent specified in the picture."

This is the layout of Stacey's house. You may think the drawing is crude, but I'm here to tell you it speaks volumes. Image credit: Stacey

Stacey, your wonderful drawing tells me all I need to know. Congrats to you for realizing the placement of the heat vents might have something to do with the problem!

One of the reasons your house is drafty is because the heat vents are not located properly.

To get even heat, and cooling if you have AC, the source of the heat / cooling should be on the exterior walls.

This is where the heat loss and heat gain is, so you want to offset the heat or cold by flooding the exterior walls with either heat or cool air (if it's summer).

The return air ducts, in a forced-air system, should be on the opposite wall so the conditioned air is pulled across the room.

If the supply ducts (for both heat and cooling) are down low on the floor or lower portion of the wall, the return air ducts should be HIGH on the opposite wall so the conditioned air travels at a diagonal across the room heating or cooling your body.

If you have a basement and your furnace is located there, you should be able to get the ductwork relocated so the supply ducts are on the outside walls.

It's VERY IMPORTANT that heat loss calculations be done so you put in the correct sized duct and number of registers in each room. 

In other words, if a room has a Btu heat loss of say 2900 Btus, you MUST inject that many each hour for the room to stay at the temperature you want. A good furnace professional knows all about this.