Most door drafts are fixed by adjusting the threshold, replacing the door sweep, or replacing the perimeter weatherstripping, all of which cost under fifty dollars in parts. Replace the door when the slab is warped, the jamb is rotted, or the frame has racked out of square.
A drafty door is not usually a broken door. It is a door whose seal has gone out of adjustment or whose weatherstripping has compressed flat after a few thousand closings.
Diagnose it in ten minutes and you will often find you can fix it yourself for the cost of a sandwich.
Find where the air is actually coming in
On a windy day, close and lock the door and run the back of your hand slowly around the entire perimeter, an inch from the surface. The back of your hand is far more sensitive to moving air than your palm. Alternatively, hold a lit incense stick near the perimeter and watch the smoke. Where the smoke bends, air is moving. Do the full perimeter: the threshold, both sides, the top, and the hinge side. Then check the trim where it meets the wall, which is a different problem entirely.
Fix by location
| Where the draft is | Likely cause | Fix | Cost |
|---|---|---|---|
| Under the door at the threshold | Threshold out of adjustment | Raise the threshold with its adjustment screws | Free |
| Under the door, threshold maxed out | Worn door sweep | Replace the sweep | $15 to $40 |
| Along the latch side | Compressed weatherstripping | Replace the perimeter weatherstrip | $20 to $50 |
| Along the latch side, strip is fine | Door not closing tight enough | Move the strike plate slightly | Free |
| Along the hinge side | Hinges loose or door has sagged | Tighten hinges, add a long screw | Free |
| At the top corner | Frame racked or door warped | Adjust hinges, or replace | Varies |
| At the trim, not the door | Perimeter never insulated | Remove trim, foam the gap, reinstall | $20 to $60 |
| Through a glass insert | Failed insert seal | Replace the glass unit | $200 to $500 |
The threshold adjustment almost nobody knows about
Look along the top of your threshold, the metal or composite piece under the door. On most modern thresholds you will see a row of screws, typically three to five, set into the sill cap. Those are adjustment screws. Turning them raises or lowers the cap so it meets the door sweep. Over years, thresholds settle and sweeps compress, and the gap opens up. Raising the threshold a couple of turns per screw, evenly across all of them, frequently eliminates a floor draft entirely. Raise it until the door closes with light resistance and the sweep contacts along its full length, then stop. Too high and the door will drag and the sweep will wear out quickly.
When it really is time to replace the door
- The slab is visibly warped, so it touches at the top and gaps at the bottom or vice versa, and hinge adjustment does not correct it.
- The jamb is soft or rotted at the bottom, which means water has been getting in and the fix is structural.
- The frame has racked out of square, so no amount of weatherstripping closes the variable gap.
- The bottom of a steel door has corroded through.
- The door is a hollow-core or uninsulated slab that was never intended for exterior use.
- You have replaced the weatherstripping twice in five years, which usually means the geometry is wrong rather than the seal.
Ranges reflect typical Capital Region projects and are for planning only. Every Sundog quote is written, itemized, and free.
Frequently asked questions
How do I stop a draft under my front door?
Start with the threshold adjustment screws along the top of the sill, which raise the sill cap to meet the door sweep. Most people do not know these exist. If the threshold is already at its maximum and there is still a gap, replace the door sweep, which costs fifteen to forty dollars and takes twenty minutes.
How often does door weatherstripping need replacing?
Roughly every five to ten years on a door in regular use, sooner on a heavily used entry. The strip compresses permanently over thousands of closings and eventually stops springing back. It is inexpensive and it is the most commonly deferred door maintenance item.
Why is my door drafty at the top corner?
Usually because the door has sagged on its hinges or the frame has racked. Try tightening the hinge screws first, and replace one screw in the top hinge with a three-inch screw that reaches the framing behind the jamb, which pulls the door back up. If the gap remains, the frame geometry has changed and that is a bigger fix.
Is the draft coming from the door or from around it?
This is the key diagnostic and people get it wrong constantly. Air at the sash or the door edge is a weatherstripping issue. Air at the trim where it meets the wall means the gap between the frame and the rough opening was never insulated, which is a completely different fix and does not require a new door. Removing the trim and foaming that gap solves it.
Is it worth fixing an old door or should I replace it?
If the slab is straight, the jamb is sound and the frame is square, fixing it is a fifty dollar project that works. If the slab is warped, the jamb is rotted or the frame has racked, you are chasing a geometry problem with weatherstripping and it will never seal. Check those three things before deciding.
Services this relates to
Keep reading
Local pages
Questions about your own house?
A free measure and a written quote costs you nothing and gives you real numbers to work with.