Cold air doesn't need a big opening to get in. A gap the width of a pencil around a window is enough to make a room feel chilly, even with the heat running.
The good news is most of these gaps are cheap and easy to fix. You just have to find them first.
Find the drafts before you fix them
You don’t need fancy tools for this. A few simple checks will tell you exactly where cold air is sneaking in.
- Hand test - Slowly run your hand around the edge of each window and door. A sudden change in temperature means air is moving through.
- Candle or incense test - Hold a lit candle or incense stick near the edges of a window or door on a windy day. If the smoke flickers or blows sideways, there’s a leak.
- Light test - At night, turn off the lights and have someone shine a flashlight around the outside of your windows and doors. Light getting through means air can too.
- Noise test - Open a window or door slightly and listen. If outside noise still comes through clearly once it’s closed, that’s a sign the seal isn’t doing its job.
The usual suspects
A few spots cause most of the trouble in a typical home:
- Windows - Old or worn weatherstripping is the number one cause of drafts here.
- Exterior doors - Gaps at the bottom are common, and easy to miss since you walk right over them.
- Electrical outlets - Outlets on exterior walls are a sneaky source of cold air.
- Attic hatches and vents - Warm air escapes here just as easily as cold air gets in.
Quick fixes you can do yourself
Most small drafts don’t need a professional. They just the right material for the job.
- Weatherstripping seals the moving parts of windows and doors, where they open and close.
- Caulking fills the small, non-moving gaps, like where a window frame meets the wall.
- Door sweeps close the gap under exterior doors.
- Foam outlet gaskets are a cheap fix for drafty outlets, and take about a minute each to install.
None of these cost much, and take an afternoon at most to get it done.
When it’s more than a quick fix
Sometimes the draft isn’t really about weatherstripping at all. Cracked frames, foggy glass between panes, or a door that doesn’t close flush anymore usually means the window or door has reached the end of its life.
Signs it’s time to consider a replacement instead of a patch:
- Condensation building up between panes of glass
- Frames that are warped, cracked, or rotting
- A door or window that's difficult to open or close
- Drafts that keep coming back no matter how many times you reseal them
If that sounds like your situation, consider replacing your windows and doors. New windows and doors are built to actually seal properly, instead of fighting a losing battle every winter.
FAQs
How do I know if my house has drafts?
Run your hand around window and door edges, or try the candle test on a windy day. If you feel or see movement, that’s a draft.
What's the cheapest way to stop drafts?
Weatherstripping and caulking. Both cost very little and can be done in an afternoon without any special tools.
Where do most drafts come from in a house?
Windows and exterior doors are the most common sources, followed by electrical outlets on exterior walls and attic hatches.
Can sealing drafts actually lower my energy bill?
Yes. Every gap you seal is less warm air escaping and less cold air getting in, which means your furnace doesn’t have to work as hard to keep up.
Should I caulk or weatherstrip?
Use weatherstripping for parts that move, like where a window or door opens and closes. Use caulk for gaps that don’t move, like around a window frame.
How do I know if I need new windows instead of sealing them?
If you’re seeing condensation between the panes, warped or cracked frames, or drafts that keep coming back after resealing, it’s usually time to replace rather than patch.
What time of year should I seal drafts?
Early fall is ideal, before the cold weather actually arrives and while it’s still comfortable to work outside.
