How to Insulate Your Home to Cut Draughts

If you can feel a breeze around a window on a still day, you are heating the outdoors. Draught proofing your home is among the cheapest and most satisfying jobs in the house: the materials are inexpensive, the tools are basic, and you often notice a difference the same evening.

Draught proofing and insulation are related but not the same. Insulation slows the flow of heat through walls, roofs and floors. Draught proofing stops air leaking through gaps. You usually want both, and this guide covers each, starting with how to find the leaks.

One important point first: a home needs some ventilation. Do not seal up chimneys, extractor fans, trickle vents or the air bricks that ventilate floors, and take extra care with rooms containing open flues, gas appliances or wood burners. If in doubt, ask a qualified heating engineer.

Find the Draughts

You cannot fix what you cannot find. On a cold, breezy day, close all windows, doors and fireplace dampers, then work through the house.

Simple detection methods

• The hand test. Move your palm slowly around frames, letterboxes, skirting boards and pipe entries. Wet fingers feel cool air more easily.
• The candle or incense test. A lit incense stick held near suspect gaps will show smoke flicker or stream sideways. Keep it away from curtains and never leave it unattended.
• The paper test. Close a door or window on a strip of paper. If it slides out easily, the seal is poor.
• Look from outside. Cracked sealant, gaps around frames and missing pointing are visible clues.
• Thermal imaging. Some energy assessors and local schemes use thermal cameras, and you can sometimes borrow one from community energy groups.

Make a list as you go, room by room. Typical problem areas are:

1. Around and under external doors
2. Window frames and sash windows
3. Letterboxes and keyholes
4. Floorboards and skirting boards
5. Loft hatches
6. Gaps around pipes and cables where they enter the house
7. Chimneys and fireplaces
8. Extractor fan housings and vents (check they have working flaps)

Doors

External doors are often the biggest culprits.

Door edges

Self-adhesive foam or rubber strips are cheap and work well on well-fitting doors. For more durable results, fit brush or wiper strips along the bottom, and compression seals around the frame. Measure the gap before you buy, since seals come in various thicknesses.

Letterboxes and keyholes

A brush-style or flap letterbox draught excluder stops cold air blowing in. Keyhole covers are cheap and effective. If your letterbox is on an internal door, you can fit a simple internal flap.

Thresholds

A worn threshold lets air under the door. You can fit a draught excluder strip on the door itself, or replace the threshold if it is warped or damaged. A fabric draught excluder across the base is a low-cost temporary fix for interior doors.

Windows

Windows leak at the moving parts, at the frame and through the glass.

Casement windows

Check the rubber seals around the opening sashes. If they are brittle or flattened, replacements are available in several profiles. Match the groove shape of your frame. Clean the channel first, then press the new seal in without stretching it.

Sash windows

Traditional sash windows are notoriously draughty. Specialist brush pile strips can be fitted in the channels, and parting bead seals can help. Heavy or damaged sashes may justify a specialist restorer. If the building is listed or in a conservation area, check restrictions before altering the windows.

Frame gaps

Cracked or missing sealant between the frame and wall lets air in. Rake out loose material, clean, and apply flexible exterior sealant. Indoors, a thin bead of decorators’ caulk around architraves helps.

Secondary glazing and curtains

Temporary or removable secondary glazing film is an inexpensive way to reduce heat loss in older windows. Heavy lined curtains also help, but keep them from covering radiators.

Floors and Skirting Boards

Gaps between floorboards and skirting boards let air in from the void below. Options include:

• Filling narrow gaps with flexible filler or mastic.
• Using strips of wood or rope in wider gaps between boards.
• Sealing along the skirting with flexible caulk.
• Laying underlay and carpet or a rug over bare boards.

Do not block air bricks on the outside, as they ventilate the void and protect timbers from damp.

Loft Hatch, Pipes and Cables

Warm air rises, so gaps at ceiling level matter. Fit foam strips around the loft hatch frame and a catch to compress the seal. Add insulation on the loft side of the hatch if it is thin. Fill gaps around pipes with expanding foam or fire-rated sealant where pipes pass through walls and floors. Choose products suitable for the location.

Chimneys and Fireplaces

An unused open chimney is a major draught source. Options include a chimney balloon (an inflatable plug), a cap on top, or a register plate. Remove balloons before lighting any fire, and make sure there is still ventilation to the flue to prevent damp. If you use a wood burner or open fire, do not block the chimney at all. Ask a HETAS-registered installer if you are unsure.

Insulation: The Other Half of the Job

Once the leaks are sealed, insulation helps keep warmth in.

Loft insulation

Most homes lose a significant share of heat through the roof, and loft insulation is a common first step. Current guidance suggests a thick layer laid in two directions, but the exact depth depends on the material and current regulations. Check government guidance for your country. Do not squash insulation against the eaves, since air needs to circulate to avoid condensation.

Wall insulation

Cavity walls can often be filled by a registered installer. Solid walls need internal or external insulation, which is a larger project that needs planning, ventilation advice and sometimes permission. Always have a qualified person survey your property for damp and cavity suitability.

Floor insulation

Insulating under suspended timber floors can be done from below with netting and mineral wool, or from above when boards are up. It is a messy job but can reduce cold floors.

Hot water tank and pipes

A well-fitting jacket on a hot water cylinder and foam lagging on exposed pipes cut waste heat and protect against freezing.

Home Improvement Ideas That Suit Any Budget in 2026

A Simple Weekend Plan

If you want a fast, effective approach, try this:

1. Friday evening: do the draught hunt and list the problem areas.
2. Saturday morning: buy materials for doors and windows. Measure carefully.
3. Saturday: fit door seals, letterbox brush and keyhole covers.
4. Sunday: seal window frames, fill skirting gaps and fit loft hatch strips.
5. Afterwards: note how rooms feel, and monitor your heating bills over the next season.

Keep your receipts and make a note of what you fitted, in case you need to replace any strips in future.

Mistakes to Avoid

• Sealing everything. Rooms with fuel-burning appliances, kitchens and bathrooms need ventilation. Keep vents and extractor fans clear.
• Using the wrong sealant. Use sealants rated for outdoor or flexible joints where relevant.
• Skipping measuring. Seals that are too thick won’t let doors close.
• Ignoring damp. If you see mould or condensation after draught proofing, you may need improved ventilation.
• Overlooking safety. Fit working smoke and carbon monoxide alarms, especially if you have gas appliances.

Home Maintenance FAQs: What to Check and When

Frequently Asked Questions

Is draught proofing worth it?

It is generally a low-cost improvement that makes rooms more comfortable and can reduce heat waste. The saving depends on your property and how leaky it is, so we avoid quoting a figure.

Will draught proofing cause damp?

Done sensibly, it should not. Keep deliberate ventilation such as trickle vents and extractor fans working, and watch for condensation.

Can I draught proof sash windows myself?

Simple brush strips are DIY-friendly. Heavily worn sashes may need a specialist.

What is the cheapest way to stop draughts?

Door brush strips, letterbox covers, keyhole covers, sealant and removable window film are all inexpensive and effective starting points.

Conclusion

Draught proofing your home does not demand specialist skills, only a methodical walk around the house and a small handful of materials. Find the leaks, seal doors and windows, deal with floors and the loft, and add insulation where it makes sense. Keep ventilation where it is needed, and you will have a warmer, more comfortable home for little outlay.