Energy & EPC

Draught Proofing Your Home, The Cheapest Way to Cut Energy Bills

Draught proofing is the most affordable energy efficiency improvement you can make. This guide covers how to draught proof windows, doors, chimneys, and floors, with estimated costs and savings.

Published: 17 Mar 2026 · Updated: 17 Mar 2026 · 7 min read

Why Draught Proofing Is the Best Place to Start

Of all the energy efficiency improvements you can make to your home, draught proofing offers the best return on investment. It is inexpensive, often under £200 for a whole house if done yourself, quick to install, and immediately noticeable in terms of comfort and reduced heating bills.

The Energy Saving Trust estimates that draught proofing windows, doors, and blocking unnecessary draughts can save a typical household £60 to £90 per year on heating bills. For older properties with significant gaps, the savings can be higher.

Unlike major insulation projects, most draught proofing work can be completed as a DIY project in a single weekend.

What Is a Draught?

A draught is an unwanted flow of cold air into your home through gaps and cracks in the building fabric. Common draught sources include:

**Windows**, gaps between the window frame and the wall, or between the sash and the frame
**External doors**, gaps around the edges, the letterbox, and the keyhole
**Chimneys and fireplaces**, open flues allow warm air to escape and cold air to enter
**Floorboards**, gaps between boards and at the junction of floor and skirting board
**Loft hatches**, poorly sealed hatches allow heat to escape into the loft
**Pipework and cable holes**, where pipes and cables pass through external walls

Draught Proofing vs Ventilation

It is important to distinguish between draughts and ventilation. Draughts are uncontrolled air leakage through gaps that were never intended to be there. Ventilation is the deliberate, controlled flow of fresh air that prevents condensation, damp, and poor indoor air quality.

**Never block or seal:**

Trickle vents in windows (the small slots at the top of the frame)
Airbricks in external walls
Extractor fans in kitchens and bathrooms
Any purpose-built ventilation grille

Blocking intentional ventilation can lead to condensation, mould growth, and in properties with gas appliances, dangerous carbon monoxide build-up.

How to Draught Proof Windows

Sash windows

Sash windows are among the draughtiest window types. The most effective solution is brush-pile draught strip, which fits into a routed groove in the frame. For a professional finish, specialist sash window draught proofing companies can overhaul the window, replacing sash cords and fitting precision draught strips. This typically costs £150 to £300 per window but dramatically reduces air leakage while preserving the character of the window.

For a budget approach, self-adhesive foam strip can be applied to the frame where the sash meets it. This is less durable but costs under £5 per window.

Casement windows (hinged)

Self-adhesive rubber or silicone draught strip is effective for casement windows. Clean the frame, measure the perimeter, and press the strip into place along the closing face. Replace annually or when the seal starts to compress.

Gaps between frame and wall

If there are visible gaps between the window frame and the surrounding wall, fill them with decorator's caulk (for small gaps up to 5mm) or expanding foam sealant (for larger gaps, trimmed and painted over once cured).

How to Draught Proof Doors

External doors

**Bottom edge:** Fit a brush strip or rubber blade excluder to the bottom of the door. These cost £5 to £15 and screw or stick to the door's lower edge.
**Sides and top:** Apply self-adhesive rubber or foam strip to the door frame where the door closes against it.
**Letterbox:** Fit a letterbox brush or flap cover on the inside. Models with both a brush and a hinged cover are most effective. Cost: £5 to £15.
**Keyhole:** Fit a keyhole cover plate that drops over the keyhole when not in use. Cost: under £5.

Internal doors

Draught proofing internal doors is worthwhile where they separate heated rooms from unheated spaces, for example, doors to hallways, porches, or utility rooms. A simple fabric draught excluder along the bottom of the door is effective and inexpensive.

How to Draught Proof a Chimney

An open chimney is one of the biggest sources of heat loss in a home. If you do not regularly use the fireplace, fitting a chimney draught excluder can save £30 to £50 per year.

Options include:

**Chimney balloon**, an inflatable device that sits inside the flue and blocks airflow. Cost: £20 to £30. Must be removed before lighting a fire.
**Chimney sheep**, a thick felt pad on a wire frame that wedges into the flue. Reusable and easy to remove. Cost: £20 to £40.
**Chimney cap**, a permanent external cap fitted to the chimney pot. Suitable if the fireplace is permanently disused. Cost: £30 to £100 including fitting.

If you do use the fireplace, ensure the chimney is swept annually and never leave a draught excluder in place when a fire is lit.

How to Draught Proof Floors

Timber floorboards

Gaps between floorboards allow cold air to rise from the void below. Options include:

**Flexible filler strips**, pre-made strips of compressible material that push into gaps between boards. Effective and reversible. Cost: approximately £1 per metre.
**Decorator's caulk**, suitable for small, consistent gaps. Apply with a caulking gun and smooth with a damp finger.
**Underfloor insulation**, for accessible voids, fitting mineral wool or rigid insulation boards between joists addresses both draughts and heat loss. This is a more involved project but delivers greater savings.

Skirting board gaps

Gaps between the skirting board and the floor or wall can be sealed with decorator's caulk. This is a quick fix that makes a noticeable difference in draughty rooms.

Estimated Costs and Savings

Measure	DIY cost	Professional cost	Annual saving
Draught proof windows (whole house)	£20–£50	£100–£300	£25–£40
Draught proof doors (whole house)	£30–£60	£80–£150	£15–£30
Chimney draught excluder	£20–£40	£40–£80	£30–£50
Floor draught proofing	£20–£100	£150–£300	£10–£25
Total	£90–£250	£370–£830	£80–£145

These figures are estimates based on Energy Saving Trust and BEIS data for a typical three-bedroom semi-detached house. Actual savings depend on the severity of existing draughts, the heating system, fuel prices, and thermostat settings.

Does Draught Proofing Improve Your EPC?

Draught proofing alone is unlikely to change your EPC band because the Standard Assessment Procedure (SAP) does not directly measure air permeability in most domestic assessments. However, it contributes to overall thermal performance and complements other measures, such as insulation and double glazing, that do improve the SAP score.

Check your current EPC rating and recommendations on Property Passport UK. If your EPC lists insulation measures alongside draughts as an issue, addressing both together will deliver the greatest improvement.

Where to Start

1. Walk through your home on a cold, windy day and feel for draughts around windows, doors, and at floor level

2. Prioritise the worst offenders, external doors and windows in frequently used rooms

3. Purchase draught strip, excluders, and caulk from any DIY store

4. Work methodically room by room, most homes can be fully draught proofed in a day

Draught proofing is the foundation of any energy efficiency plan. It costs very little, delivers immediate comfort, and makes every other improvement, from insulation to heat pumps, work more effectively.