Draught proofing: Stop losing heat through gaps you can't see

Draught proofing means sealing the gaps where cold air enters and warm air escapes. Uncontrolled air leakage can account for a significant portion of a home's heat loss (often up to around 20–30% in older or draughty properties), yet it is one of the cheapest and most effective improvements you can make.

Why draught proofing matters

Draughts make your home feel colder than it actually is. Cold air creeping in around windows, doors, and floors forces your heating system to work harder, drives up your bills, and creates that uncomfortable feeling of feeling cold, even with the heating on.

Sealing these gaps is one of the first things worth doing because every other improvement works better afterwards. Insulation performs better in an airtight home and heat pumps run more efficiently when they are not fighting air leakage. Draught proofing underpins everything else.

Where draughts come from

Most draughts come from small gaps that are hard to see but easy to feel. Here are the most common sources and what can be done about them.

	Common solutions	Typical difficulty
Modern windows	Improve sealing around the frame	Moderate
Sash windows	Secondary glazing, draught strips, or replacement with modern uPVC sash units	Professional recommended
Doors	Door sweeps (brush or rubber), threshold seals, rubber gaskets around the frame	Mostly DIY-friendly
Letterboxes and keyholes	Sprung-close covers, purpose-made draught excluders	DIY
Floors and skirting	Airtightness tape, foam sealant, gaskets between boards	Moderate - may require lifting floorboards
Chimneys	Chimney balloon (inflatable, reversible) or removable ventilated seal	DIY for balloons, professional for permanent sealing
Loft hatches	Foam strips or weather stripping around the frame	DIY
Pipes and cables	Filler, sealant, or expanding foam around entry points	DIY

What to be aware of

Many of the fixes in the table above are straightforward, but knowing where to focus is the hard part. The most significant draughts are not always the most noticeable draughts. Hidden gaps behind skirting boards, around pipe penetrations, and within the building structure often account for more heat loss than the obvious draught under the front door.

A professional air permeability test measures exactly how much air your home is losing and where. Without that data, you're often relying on assumptions, and often spending time on areas that make little difference while missing the ones that matter most.

It is also worth noting that not all airflow should be stopped. Homes need controlled ventilation to manage moisture and maintain air quality. Draught proofing seals the uncontrolled leaks. It does not replace the need for proper ventilation.

"Homes need controlled ventilation to manage moisture and maintain air quality, especially after draught proofing improvements. This may include trickle vents, extractor fans or whole-house ventilation systems."

Austin Bedford, Home Energy Expert at Furbnow

How Furbnow approaches draught proofing

Our whole-house survey includes an assessment of your home's air leakage - identifying where the biggest gaps are, which ones are worth sealing, and how draught proofing fits alongside other improvements like insulation and ventilation. We don't treat it in isolation because it doesn't work in isolation.

Stop paying for heat you're not keeping

A Furbnow Home Energy Plan identifies where your home is losing heat through air leakage and sets out the right fixes in the right order, so nothing gets missed and nothing gets done at the wrong time.