Question

I live near Toronto, Canada ... and it can get cold in the winter. Today, it's -10C outside, and I've seen it get as cold as -17C. Though it could be worse, I know people from Winnipeg!

Anyway, one of the bedrooms upstairs in our house is colder than the other rooms, usually by about 2C. For instance, when the master bedroom is 22C, that room is 20C. I suspect it's because our home has a forced-air furnace system and that bedroom is the only room upstairs without a cold air return duct. (Darn builder didn't put one there!)

So, aside from actually installing a duct – tricky – what else can we do to address the situation?

I was considering additional attic insulation for the house (going from R-32 to R-50)... would that make a big difference?

... or else replacing the window in that room; it's 4x3 feet, approx. and double pane, nothing spectactular, just builder typical. Would a good window make a big difference?

Would removing the drywall and using spray-foam insulation have a marked effect? Two of the walls for that room are outside walls.

I'd like to know what you think of the above ideas, as well as any I haven't thought of. Thanks!

Answer 1

To be honest, 20C is plenty warm enough, our house is usually 17-19C, except in areas we spend a lot of time sat still (like in front of my TV). Some simple and less invasive remedies are to hang heavy curtains (drapes) in front of the window, get thicker sheets or wear a sweater. Is there a reason why the room needs to be so warm?

Addressing your questions directly, I'd probably treat the attic, then the windows, then the walls in that order, this is based on the cost, mess and efficiency of the treatments.

Attic insulation is a simple and cost effective way to warm the whole house. If you have less than 250 mm (10") of insulation, consider laying some more, especially with a 35^o difference between inside and out. You don't even need to take up the old stuff, just lay the additional insulation on top, at right angles to the original and don't pack it down - the trapped air is doing the insulation not the fabric.

For a given area, windows account for far greater heat loss than walls, so if the window is old or the cavity is blown replacing it can have a huge benefit. If it is fairly modern it will be of less benefit. Aluminium frames in particular are excellent conductors and efficiently transport heat out of the room to the outside. A simple way to check if your windows could be improved is to hold your hand about 10 cm (4") from the pane, if you can feel the cold it is probably not doing an optimal job. The latest triple-glazed units have U values comparable to basically-insulated walls so hold the heat very well.
One complication with triple glazing is that they are such efficient insulators, that they limit the heating effect of the sun, so overall can actually be counter-productive on a sunny elevation. If your window is North facing (or South facing down under) then triple glazing is a big win though.

If you have no cavity insulation, then you could hire someone to come round and inject your walls with it. I'm not up on the codes in Canada I'm afraid, but I've seen services in the UK and US that will cut a hole into the wall (for timber frames there'll typically be a hole between each upright) and blow insulation into the cavity, this is less invasive than ripping off all the drywall and the holes can simply be patched and skimmed.

Answer 2

We just recently moved into a freshly renovated house. The one thing missing was the attic insulation, and it was really noticably colder in those rooms. After we put a total of nearly 40cm styrofoam insulation there, it's fine now. As Rich said already: attic, then window, then wall.