What this comes down to
- New weatherstripping often fails because the door has stopped fitting, so the fit gets fixed first.
- The Department of Energy says to fix loose hinges, knobs and strike plates before weatherstripping.
- A porch light at night and a dollar bill shut in the door find most leaks without any tools.
- Doors account for 11 percent of the heat loss in a typical home, according to the State of Illinois.
- A door that seals on three sides and not the fourth is likely bent, and no strip will cure that.
- Perfect Work lists door jamb repair from $195 and replacement from $695, after the leak is located.
A draft around an exterior door is air finding a gap. The gap sits on one of five edges. They are the bottom, the latch side, the hinge side, the top and the frame behind the trim.
This guide traces a draft to its source the way a repair visit does. It draws on the Department of Energy, a national laboratory, the State of Illinois and ENERGY STAR. It covers the tests, the fixes and the cost.
Where does a draft around a door come from?
From five places. The bottom is the first to check, because sweeps wear and thresholds settle. The latch side leaks when the strike plate has loosened. The hinge side leaks when the hinges have let the door sag.
The top leaks when the door has dropped away from the head jamb. The fifth source is the frame itself. Gaps between the jamb and the wall framing let air move behind the trim.
The state guidance on doors puts them at 11 percent of heat loss in a typical home. ENERGY STAR says sealing leaks and insulating can save up to 10 percent a year. Its seal and insulate page counts the whole house, not one door.
How can I find the leak?
Three cheap tests find most leaks. Feel along the edges, or hold a tissue to the frame, with the windows shut and the exhaust fans on. At night, turn on the porch light, switch off the lights inside and look for light around the door.
The third test uses a dollar bill. Close the door on the bill and pull it. If it slides out easily, air is leaking at that spot. The Pacific Northwest National Laboratory lists all three in its guide to weatherstripping doors.
Test every edge, not just the coldest. A bill that grips at the hinges but slides at the latch means the door is not closing flat. That is a fit problem, not a seal problem.
Why does new weatherstripping not stop a draft?
Because the door has to fit the frame before any strip can seal it. The Department of Energy's weatherization job aid says to repair or adjust the door first. That includes loose hinges, knobs and strike plates.
The same sheet names daylight around the door and a loose fit as the first signs. A strip pressed onto a sagging door only hides part of the gap. The rest keeps passing air all winter.
The State of Illinois adds a useful check. After new stripping goes on, the door should seal on all sides of the jamb. If it does not, the stripping was poorly installed or the door is bent and may need replacing.
What fixes a draft at the bottom of the door?
A door sweep or a door shoe usually does. The PNNL guide describes a sweep as a brushed metal strip fixed inside an in-swinging door. Many are adjustable for an uneven threshold.
A door shoe has a vinyl insert that seals the gap and sheds rain. The guide calls it fairly expensive, and the door bottom may need planing. A bulb threshold wears under foot traffic.
When the sweep is new and the gap stays, the threshold may be worn or the door may be hanging low. The guide to threshold replacement covers that case. Either one needs carpentry, not another strip.
What fixes a draft at the sides and top?
A compression strip along the jamb does, if the door closes on it firmly. PNNL rates tension seal, a vinyl or bronze V-strip, as very effective on the top and sides. Magnetic tape works in the same places.
Illinois guidance says to run one continuous strip per side and meet the corners tightly. The strip should press firmly without making the door hard to close. PNNL calls felt the least effective.
Strips only work where the door meets them evenly. A door that needs a shove to latch has a fit problem first, and no strip will cure it. The guide to a door that won't latch explains.
When is the draft coming from the frame?
When the door seals well and cold air still comes in around the trim. PNNL says significantly colder air around a frame means weatherstripping alone may not be enough. Pulling the trim shows whether the rough opening was sealed.
Illinois guidance says a pre-hung door needs a square frame to seal and swing. It says to seal the frame to the rough opening with low or non-expanding foam. A frame rotted at the sill cannot hold that seal. The rotted door frame signs show how to spot it.
How do the common drafts compare?
| Where you feel it | Likely cause | Usual fix |
|---|---|---|
| Along the floor gap | Worn sweep or a door hanging low | New sweep or shoe, then adjust the door |
| At the sill under the slab | Worn or settled threshold | Adjust or replace the threshold |
| Latch side | Loose strike plate, door not closing flat | Tighten and reset the strike, then re-strip |
| Hinge side | Loose hinges, a sagging door | Tighten or shim the hinges, then re-strip |
| Top edge | Door dropped from the head jamb | Adjust the fit, then a compression strip |
| Around the trim | Gap between frame and wall framing | Pull the trim, foam the opening, check for rot |
| Seals on three sides only | Bent door or a frame out of square | Replace the door or reset the frame |
What does fixing a door draft cost?
Perfect Work Remodeling & Repairs lists door jamb repair from $195 and replacement from $695. Time on site is billed at $65 per hour, with a $99 minimum. These are starting prices, not quotes.
| The work | Starting price | What moves it |
|---|---|---|
| Door jamb repair | From $195 | Hinge side wear and how far the door has sagged |
| Rotted door frame repair, localized | From $249 | How far the rot runs into the sill and jamb |
| Exterior door replacement, installed | From $695 | Door type, size and frame condition |
| Handyman hourly rate | $65 per hour | Hours on site and materials |
| Minimum service call | $99 minimum | One visit and travel |
A sweep or strip swap is small work and runs at the hourly rate. A door that has dropped usually needs the hinge work in the guide to a door that won't close. A bent door or a rotted frame changes the job.
What cannot be determined from the surface?
Where air enters behind the trim, and how much. The Department of Energy's job aid confirms sealing with a blower door and a smoke test. Hand tests find only what shows at the edges.
It also cannot show that a door is bent until new strips fail to seal on one side. Only a fit check with the door closed settles that, and it takes a few minutes.
Door draft questions
Why do I feel a draft with my door closed?
Air is passing through a gap at the bottom, the sides, the top or the frame. Worn weatherstripping and a door that no longer fits are the usual causes. A dollar bill shut in the door and a porch light at night will show where.
How does Perfect Work find where a door draft comes from?
Perfect Work Remodeling & Repairs tests every edge with a paper strip. It also checks the hinges, the strike and the sweep. It looks behind the trim if cold air still comes in around the frame. A door that seals well is left alone.
Can a sagging door cause a draft?
Yes. The Department of Energy says to fix loose hinges, knobs and strike plates before weatherstripping. A door that has dropped leaves a gap at the top and latch side. Strips cannot close a gap that the hinges keep reopening.
What does a door draft repair from Perfect Work include?
Perfect Work Remodeling & Repairs lists edge tests, hinge and strike fixes and a seal check. A new sweep or strips are included. Door jamb repair starts at $195. Frame rot or a bent door is added once found.
Should I replace a drafty door or fix it?
Fix it when the door is straight and only the strips or fit are off. Replace it when it is bent or will not seal on all sides. Illinois guidance says insulated steel or fiberglass doors seal and insulate better than wood.
Does a storm door stop a draft?
It can help an old door in good condition. Illinois guidance calls a storm door costing about $200 or less generally worthwhile for that case. On a modern foam-core door it usually saves little energy.
Find the gap before you buy the strip
A strip bought before the leak is found is usually the wrong strip. Locating the edge that leaks takes ten minutes and a porch light. It keeps the money for the fix that matters.
A visit from Perfect Work Remodeling & Repairs starts with the gap and the fit of the door. The door repair services page lists the repairs that can follow once the cause is known.
Call Perfect Work at 630-297-7888 · Book a door check