If you can feel cold air around your windows, your home is losing heat — and money.
Window draughts are one of the most common causes of uncomfortable rooms in UK homes. Even modern double glazing can allow air through if seals, frames or installation gaps have failed.
The good news: most window draughts are fixable without replacing the entire unit.
In this guide, you’ll learn how to identify the source of the draught and how to fix it properly.
Why Do Windows Let in Draughts?
Draughts usually come from one of five areas:
- Worn or compressed rubber seals
- Gaps between frame and wall
- Failed external silicone
- Poorly adjusted hinges or locks
- Gaps between opening sash and frame
Cold air follows the path of least resistance. Even a 1–2mm gap can cause noticeable airflow.
If you’re unsure whether the issue is condensation rather than air leakage, see Condensation vs Damp: How to Tell the Difference
Step 1 – Find the Exact Source
Before sealing anything, identify where the air is entering.
On a windy day:
- Run your hand slowly around the frame
- Use tissue paper or incense to detect airflow
- Check corners carefully
- Inspect both inside and outside
Common problem areas:
- Top corners of opening windows
- Between frame and plaster
- Under window boards
- Around hinges
Accurate diagnosis prevents unnecessary work.
Fix 1 – Replace Worn Window Seals
If the rubber gasket feels:
- Hard or brittle
- Flattened
- Shrunk at the corners
- Loose in the groove
It needs replacing.
Most uPVC windows use push-fit wedge or bubble gaskets.
Remove a short section and measure it before buying replacements.
If you’re unsure how to choose correctly, see Best Weatherstripping for uPVC Doors (seal selection principles apply to windows too).
Fix 2 – Adjust Window Hinges or Locks
If the window closes but does not compress tightly against the seal, cold air can pass through.
Check:
- Does the handle feel loose?
- Is there visible daylight when closed?
- Does pressing the frame reduce the draught?
If pressing reduces airflow, compression is the issue.
Hinges or locking cams may need adjustment or replacement.
This is common in older uPVC casement windows.
Fix 3 – Seal Gaps Between Frame and Wall
If air is entering between the frame and brickwork or plaster, the issue is installation-related.
Internal Gaps
Use decorator’s caulk between:
- Frame and plaster
- Frame and window board
Remove cracked material before resealing.
External Gaps
Inspect the external silicone line.
If cracked, lifting or missing:
- Remove failed sealant fully
- Clean and dry the surface
- Apply exterior-grade frame sealant
- Smooth to create a continuous barrier
If you suspect a deeper cavity behind the frame, see Best Expanding Foam for Door and Window Gaps
Fix 4 – Temporary Measures (Short-Term Only)
If you need a quick fix during winter:
- Self-adhesive foam strips
- Thermal window film
- Heavy lined curtains
These reduce airflow but are not long-term solutions.
They are best used while arranging a proper repair.
Fix 5 – Check the Window Locking Mechanism
Multi-point locks pull the sash tight against the frame.
If:
- The handle does not fully engage
- The mechanism feels loose
- The window moves slightly when locked
The internal gearing may be worn.
Replacing the locking strip can restore compression.
When Draughts Indicate Larger Problems
Seek further investigation if:
- The frame moves visibly in the wall
- Brickwork around the window is cracked
- Water enters during heavy rain
- Condensation forms between double glazing panes
If moisture appears inside the glass unit itself, read Why Is There Condensation Inside My Double Glazing?
Prevention Tips
To prevent future draughts:
- Inspect seals annually
- Replace gaskets every 10–15 years if needed
- Reapply external silicone every 5–10 years
- Keep drainage channels clear
- Avoid slamming windows
Small maintenance checks prevent heat loss later.
Quick Checklist
If stopping window draughts:
- ✔ Identify exact airflow source
- ✔ Replace worn rubber seals
- ✔ Reseal external frame gaps
- ✔ Adjust hinges if compression is weak
- ✔ Avoid temporary fixes as permanent solutions
Related Guides
- Best Weatherstripping for uPVC Doors
- Best Expanding Foam for Door and Window Gaps
- How to Seal Gaps Around a Front Door Frame
- How to Stop a Draught from a Front Door
- Condensation vs Damp: How to Tell the Difference
Draughts around windows are rarely caused by the glass itself.
They come from seals, compression or installation gaps.
Fix the source properly — and you restore comfort, reduce heat loss and protect your home long term.