How Much Draught Proofing Do I Need?

How We Calculated This

For a typical 3-bed semi-detached house:

• External doors (2): 2 × 5.5m perimeter = 11m
• Internal doors (6): 6 × 5.5m = 33m (optional but effective)
• Windows (8): 8 × 3.5m average perimeter = 28m
• Letterbox, keyholes, cat flap: add 2–3m equivalent
• Total: approximately 45–60m

Types of Draught Proofing

• Self-adhesive foam strip: Cheapest (~£2–5 per 5m roll). Compresses into gaps. Replace annually
• Rubber (P, E, or D profile): More durable. £5–10 per 5m. Lasts 3–5 years
• Brush strip: Good for sliding windows and letter boxes. Long-lasting
• Compression strip (metal/plastic): Most durable for doors. Professional fit
• Under-door brush strip: £5–15 each. Screws to door bottom

Where to Draught Proof

• External doors: All four edges plus bottom threshold
• Windows: Opening edges where sashes meet frames
• Letterbox: Brush or flap cover
• Keyholes: Drop cover plate
• Loft hatch: Foam strip around perimeter
• Floorboards: Flexible filler between boards
• Pipework holes: Expanding foam or silicone sealant

Cost Savings

The Energy Saving Trust estimates draught proofing saves £45–60 per year on heating bills for a typical home. It’s one of the cheapest and most effective energy-saving measures, costing £50–200 DIY or £200–400 professionally installed.

Important Note

Do not draught proof rooms with open-flue gas appliances, as they need ventilation for safe combustion. Do not block trickle vents in windows — these provide background ventilation required by Building Regulations.