Draughts coming through doors and windows
A draught coming through a closed window or door is a clear sign that the weatherproofing has failed somewhere in the frame. It's uncomfortable, it costs money in heat loss, and it's usually straightforward to fix once the actual cause is identified.
What causes draughts through closed windows and doors
There are several distinct causes, and identifying the right one matters - each requires a different repair.
Failed compression gaskets
The most common cause of persistent draughts through a closed frame. The rubber or foam gasket that runs around the opening edge of windows and doors is designed to compress and create an airtight seal when shut. Over time, gaskets harden, lose their profile, shrink at corners, or detach from the channel. Once compression is lost, air passes through freely.
This is the cause if the draught is consistent regardless of weather - if it's cold whether it's windy outside or not, gaskets are almost certainly involved.
Failed external perimeter sealant
The flexible bead running around the outside of the frame where it meets the masonry. When this cracks or lifts, gaps form between frame and wall. In windy conditions, air can be driven through these gaps into the reveal and appear to come through the frame. This tends to be more noticeable in windy conditions rather than simply cold ones.
Warped or distorted frames
Timber frames in particular can absorb moisture and distort over time, meaning they no longer close fully against the weatherseal. In this case, replacing the gasket alone won't fully resolve the problem - the frame may need adjustment. Aluminium and UPVC frames can also distort if poorly fitted originally, though this is less common.
Poor original installation
On some properties, particularly where windows have been replaced in the past, frames were never fitted with adequate perimeter sealing. There may never have been a proper joint between frame and masonry. This is worth checking on any property where the windows were replaced more than 15 years ago.
How to identify where the draught is coming from
Two simple methods work well for this:
Hand test: On a cold or windy day, slowly move the flat of your hand around the closed frame - the perimeter between frame and masonry, and around the edge of the sash or door leaf. Where you feel cold air, that's where the seal has failed. The location tells you whether it's the external joint (gap between frame and wall) or the internal gasket (gap at the sash edge).
Candle test: Hold a lit candle or lighter flame slowly around the same perimeter points. Movement in the flame indicates air movement. Do this carefully - the flame is for detection only, and should be kept well clear of anything flammable.
These tests help you describe the problem clearly before we attend, and they help us confirm the diagnosis on-site.
Energy efficiency and the real cost of draughts
Failed seals and gaskets have a direct financial impact. Cold air entering through frames means the heating system works harder to maintain room temperature - the heat you're paying for is leaking out through the same gaps the cold is coming in through.
On a typical semi-detached property with several windows showing draught failure, the annual heating cost increase can be meaningful. Gasket replacement and perimeter resealing are among the most cost-effective improvements a homeowner can make to the building fabric.
Why draught excluders and tape are not a solution
Temporary draught excluders - brush seals, foam tape, door snakes - address the symptom only and have a short lifespan. They also tend to interfere with the operation of windows and doors. The correct fix is to replace the component that has failed. A properly fitted gasket will last 15 to 25 years. A strip of foam tape around the frame will fail within a season or two.
The connection between draughts and condensation
Cold air entering around frames reduces the surface temperature of the inner reveal and glass. When warm, humid room air contacts these cold surfaces, condensation forms. This is why condensation appearing on window reveals or at frame edges is often caused by draught failure rather than general humidity. Addressing the draught reduces the cold surface temperature and usually reduces condensation in these locations.
The right repair for each cause
For failed gaskets: We remove the perished material and fit compatible replacement gaskets that restore correct compression. See our window and door seal replacement service for detail.
For failed external sealant: We fully remove the old bead and apply new sealant in the correct profile. See our external sealant replacement service for detail.
For warped frames or poor original installation: We assess what's needed - this may involve frame adjustment, new perimeter sealant, or in some cases recommending frame replacement if the frame itself is too far gone.
Frequently asked questions
Q1. What causes draughts through a closed window or door? Draughts through closed frames are almost always caused by a failed or missing compression gasket - the rubber seal inside the frame that presses against the sash or door leaf when closed. Over time, gaskets harden, split or shrink and no longer form a tight seal. Failed perimeter sealant on the external joint can also allow cold air in at the wall junction, though this is a secondary route. If the draught is felt around the frame edge itself, gasket replacement is usually the correct fix. Q2. How much heat and energy am I losing through a draughty frame? Draughts represent uncontrolled air infiltration - cold air replacing warm air continuously. While it is difficult to give a precise figure without a full energy assessment, a window with a failed gasket can make the room noticeably colder and place additional load on your heating. With energy costs at current levels in the UK, fixing draught entry points is one of the quickest returns on a building maintenance investment. Northern Seal & Joint regularly carries out seal replacement work in Yorkshire as part of thermal improvement projects. Q3. Can draught excluders or foam tape fix the problem? They can provide temporary relief but are not a long-term solution. Stick-on foam draught strips or brush excluders degrade quickly and rarely match the performance of a properly fitted compression gasket. They are also not a substitute for external perimeter resealing where the joint between frame and masonry has failed. If your windows have been poorly sealed for years, the frame reveals and surrounding masonry may also have moisture damage that a foam strip will not address. Q4. How do I identify exactly where the draught is coming from? Run your hand slowly around the closed frame on a cold, windy day - you should feel cold air where the seal has failed. A lit incense stick held near the frame will show air movement more clearly. Check both the frame-to-glass or frame-to-sash junction (gasket) and the frame-to-wall junction (perimeter sealant). If the draught is at the very edge of the frame where it meets brickwork, it is a sealant issue; if it is where the window closes, it is a gasket issue. Q5. How much does draught-proofing a window or door cost? Gasket replacement or external resealing on a single window is typically a relatively modest cost. The exact price depends on frame type, whether it requires gasket replacement, perimeter resealing or both, and the number of windows involved. Northern Seal & Joint provides written quotes covering all elements, so you are not faced with unexpected additions once work starts. Most residential draught-proofing jobs across Yorkshire are completed in a single visit. Q6. Will fixing draughts also reduce condensation on the glass? Partially. Condensation on the inner pane of a double-glazed unit is usually caused by a failed sealed unit, which Northern Seal & Joint does not repair - that is a glazing company job. However, condensation on the reveals, frame surround or wall corners is often linked to cold surfaces caused by draughts and poor sealing. Fixing the seal raises surface temperatures in those areas, which reduces the risk of surface condensation and the mould growth that typically follows.
Recent local work -
When draughts point to a bigger problem
Occasionally a draught is a symptom of something more than a failed seal or gasket. If you're experiencing persistent cold air infiltration alongside damp patches on the internal reveal, peeling paint or plaster around the frame, or visible gaps between the frame and the surrounding masonry, the issue may involve water ingress as well as air movement.
In these cases, a draught fix alone won't resolve the underlying problem. Water tracking through a failed external joint can saturate the reveal, damage the plaster, and in solid wall properties work its way further into the fabric of the building. Getting the repair sequence right matters - resealing without addressing any existing moisture damage can trap damp behind the new sealant.
If you're in Bradford, Leeds or Harrogate and the draught problem comes with any of these additional signs, a Building Leak & Damp Inspection may be the right starting point. We'll identify exactly what's failed, in what order it should be repaired, and give you a clear written report before any work begins.