Windows: Stopping the Draft You Can Feel
Alright, we've been doing doors and V-strip for a few lessons now. Let's get back to windows, because windows are where a lot of you are actually feeling this problem. You walk by in January, your hand's near the glass, and there's just cold air moving. That's what we're fixing today.
First thing: figure out where the draft's actually coming from before you touch anything. Same rule as always, diagnose before you fix. People grab a caulk gun and start going at the frame when the problem's actually the sash not sitting tight, or a lock that isn't doing its job. Slow down for a minute and find it.
Find the draft
Cheapest tool for this is your hand. Close the window, run your fingers slowly around the whole frame, top, bottom, both sides, where the two sashes meet in the middle. You'll feel it, especially on a cold day. If you want to get fancier, a lit candle or incense stick will show you the air moving, the flame or smoke will flicker right at the leak. I don't usually bother, my hand's good enough for me, but if you've got kids helping you it's a fun way to get them into it.
Write down where you found leaks. Most old windows have more than one.
The sash lock nobody uses
Here's the thing almost nobody checks, and I'm including myself for about a year. That little lock where the top and bottom sash meet in the middle, the one you flip to lock the window shut. A lot of people never touch it. They just push the window down and call it closed.
That lock isn't decoration. When you flip it, it actually pulls the two sashes together and snugs them tight against each other and against the frame. Without it, there's a gap right at that meeting rail, and that gap is a super common spot for a draft, right along with being the spot that makes the window rattle every time the wind kicks up.
I'll tell you the embarrassing version of this. My own bedroom window rattled every time it got windy, for about a year. I complained about it constantly. My kids knew about it. I kept meaning to look at it and never did, because I'd built it up in my head as some bigger project. Finally one Saturday I actually looked at the lock and it was just loose, barely catching. Fifteen-dollar part at the hardware store, twenty minutes with a screwdriver, done. A whole year of noise and cold air for a fix that cheap. So check your lock first. Genuinely, before you do anything else on this list, go flip your sash locks and see if they're even catching properly.
Weatherstripping the sash itself
If the lock's fine and you're still feeling air, the weatherstripping between the sash and the frame has probably worn out or was never there to begin with, especially on older wood windows.
For the channels where the window slides up and down, I like a V-strip, same stuff we talked about for doors. Cut it to length with scissors or a utility knife, peel the backing, and press it into the channel so the V opens toward the gap. Close the window and check that it's not so tight the sash won't move. You want contact, not a fight.
For where the sash meets the frame at top and bottom when it's closed, a compressible foam or rubber strip works better than V-strip. Press it onto the clean, dry surface, let it cure if it's adhesive-backed, don't touch it for a few hours.
I've said this before but it's worth saying again here: skip the cheap felt stuff. It flattens out in one season on a spot that already gets a lot of friction and movement, and you're back at the hardware store come next fall. Spend the couple extra bucks on V-strip or rubber and only do it once.
Caulking the frame
If your draft's coming from where the window frame meets the wall, not the moving parts, that's a caulk job, not a weatherstripping job.
Clean out any old cracked caulk first with a putty knife. Make sure the surface is dry. And check the temperature on the tube before you start, this matters more than people think. I caulked a whole window one February morning because I had the time and didn't want to wait. It never cured right. By March it was peeling off in strings and I did the whole thing over. Read the tube, and if it's too cold, wait for a better day or do it inside if you can.
Run a bead along the gap, smooth it with a wet finger or the putty knife, and leave it alone while it cures.
What this won't fix
If your window is a double-pane and you're seeing fog or moisture between the panes, none of this helps. That's a blown seal and it's a replacement job, not a weatherstripping job. I know because I spent an evening once trying to reseal a foggy window myself before finally admitting defeat. Save yourself the evening, that one I'd already lost before I started.
Before next time
Do the hand test on every window in your place and write down what you find. We'll fix them next lesson, so just gather the information for now.