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Performance · The problem library

Why is my house so draughty, and where should I look first?

Recently reviewed·Reviewed June 2026, next review December 2026

Draughts are the visible part of air leakage, which is one of the largest sources of heat loss in older UK homes. The leaks are rarely where homeowners look first. Floors, loft hatches, unsealed pipework, chimneys and downlighters often leak more than the windows that get blamed. A methodical inspection costs nothing and reveals most of them in an afternoon.

Editorial confidence
High confidence. Multiple regulator, government or academic sources agree.
Evidence status
Recently reviewed · reviewed June 2026 · next review December 2026
Monitoring
Annually, plus whenever Approved Document L airtightness guidance or ATTMA TSL1 is updated.
Evidence drawn fromBuilding standards: ADL, ADFProfessional bodies: EST

You may not need to read the rest of this page

You probably already have enough to act if:

  • Curtains move when windows are closed
  • Loft hatch and chimney have never been sealed
  • Suspended timber floors meet the wall without a sealed perimeter
Open the airtightness guide

This is probably the wrong page for you if:

  • The property is a recent airtight new build
  • There are open-flued combustion appliances and no plan for ventilation upgrade

Pre-1980 typical air permeability

10-15 m³/h·m² @ 50Pa

Source: Building Regulations; Approved Document L · Indicative range for un-retrofitted UK housing measured against the Part L test; targeted draught-proofing typically halves this.

Who this advice is for

Applies to

  • Pre-1980 UK houses with suspended timber floors and uninsulated lofts
  • Properties with original sash windows and unsealed loft hatches
  • Houses with redundant chimneys or unsealed service penetrations

Not intended for

  • Modern airtight new builds (different remedies apply)
  • Buildings reliant on background ventilation for combustion appliances
  • Diagnosing damp rather than air movement

What it usually looks like

These are the symptoms readers describe most often. None of them alone is diagnostic, but together they build a picture.

  • Cold feet near windows and skirting
  • Curtains move when shut
  • Difficult to keep rooms warm despite heating running
  • Visible draught around the loft hatch

Most common in: Victorian terrace · Edwardian semi-detached · Interwar semi (1920s–1930s)

Before you buy anything

Watch the house respond as you scroll.

These checks are listed in the order we would work through them. The illustration on the left changes with each one, so you can see what each check is actually addressing before deciding whether it is worth doing.

Heat leaves through every uninsulated surface. The room cools faster than the boiler can refill it.

01

Walk the house on a cold, windy day with a piece of thin tissue

Tissue moves where you cannot feel the draught. Most leakage points become obvious in fifteen minutes of methodical checking.

02

Inspect the loft hatch and any access panels

An unsealed loft hatch is often the largest single leak in the entire house. Foam strip and a simple latch cost very little.

03

Look at floors that run over an unheated void

Suspended timber floors can be the second largest leak. Sealing the perimeter between floor and wall is more effective than insulation alone.

04

Check the chimney, even if it is decorative

An open chimney is a permanent draught path. A chimney balloon or sheep solves it without removing the fireplace.

05

Consider an airtightness test before any major fabric work

A blower-door test gives you a numerical air leakage rate and a map of where it is happening. It is the only way to know whether the work was worth doing.

Before you spend money

The cheapest answer is usually the one nobody sold you.

  1. 01

    Walk the house with a lit candle on a windy evening

    Air leaks reveal themselves immediately. Half an hour with a candle gives a better leak map than most paid surveys.

    Free
  2. 02

    Seal the loft hatch, chimney and service penetrations first

    These three account for the majority of whole-house air leakage in older UK homes; a £30 hatch seal and a chimney balloon often outperform any window upgrade.

    £30
  3. 03

    Add brush strips to letterboxes and exterior doors

    Doors and letterboxes are the most felt draughts and the easiest to fix; ten minutes' work changes how the hall feels for the rest of winter.

    Free
  4. 04

    Use removable seal strip on the worst windows for a season

    Reversible, cheap and reveals whether a window genuinely needs replacing or just needs the gap closing.

    Free

What we recommend, and why

Every recommendation explains why it comes first, the evidence behind it, how confident we are, and when it would not apply.

01

Find the leaks before sealing anything

Why this comes first

Most leakage hides in places homeowners do not check first: loft hatches, floor perimeters, service penetrations and chimneys. A methodical walk-through with thin tissue costs nothing and reveals where work is worthwhile.

Evidence

EST draught-proofing guidance and Part L airtightness commentary both treat leakage diagnosis as a precondition for any meaningful sealing programme.

EST · ADL

Confidence

High confidence. Multiple independent sources agree on the direction and the order.

Exceptions
  • Properties where a blower-door test is already commissioned
Next step
See the draughts walkthrough
02

Respect required ventilation when sealing

Why this comes first

Sealing without retaining required background and combustion ventilation causes condensation, mould and in some cases dangerous flue-gas spillage. The right airtightness target depends on what ventilation strategy replaces uncontrolled leakage.

Evidence

Approved Documents F and L together set the rule: as airtightness improves, designed ventilation must take over from accidental infiltration.

ADF · ADL

Confidence

High confidence.

Exceptions
  • Properties without combustion appliances and with excess natural ventilation
Next step
Read the ventilation guide

The trade-offs

Every choice gives you something and asks for something back.

  • Targeted DIY draught-proofing (hatch, chimney, doors, skirting)

    You get

    A noticeably warmer feeling house for under £100, and a clear sense of what is left to fix.

    You give up

    A weekend, the patience to do it properly and the willingness to do it twice if the first pass missed gaps.

  • Professional airtightness improvements (tapes, membranes, sealed perimeters)

    You get

    A measurable cut in air-change rate and a fabric ready for a heat pump or MVHR.

    You give up

    Several thousand pounds, the discipline to do this alongside controlled ventilation, and a season of disruption.

  • Replace windows and doors

    You get

    Better acoustic and thermal comfort and an end to the worst single-source draughts.

    You give up

    A five-figure cost that rarely pays back on energy alone, and the risk of leaving leakier areas (loft, floor, chimney) untouched.

Real homes that faced this

Publicly documented UK projects that ran into the same problem and reported what happened.

We did not run these projects. Each links back to the original publisher so you can read the figures in context and judge for yourself what carries over to your home.

How we'd approach this

Seal the boring stuff first; only then talk about windows.

If this were our house we would do the unglamorous half-day work before anyone quoted us for anything. A sealed loft hatch, a chimney balloon, brush strips on the front door, foam round the service penetrations. None of it is interesting and almost all of it pays back inside a winter.

We would then walk the house in the worst weather we could find, candle in hand, and write down what is left. The honest list is usually shorter and cheaper than the one in our heads. Most 'draughty' houses turn out to have three or four real leaks rather than a building-wide problem.

We would resist the urge to seal everything. A house with combustion appliances or active condensation needs controlled ventilation, not less ventilation; over-sealing without a plan is how you trade draughts for mould. The right answer is targeted airtightness paired with a deliberate way for fresh air to enter.

Evidence behind this page

Every recommendation on this page is traceable to its source. Click a publication to read the original.

Products that may help

Only consider these once the checks above have been ruled out. A product fitted into the wrong cause is rarely satisfying.

House Summary

The cheapest answer to draughts and air leakage is usually the one that addresses the cause rather than the symptom. The list above is in the order we would work through it, because the checks at the top tend to rule out the most expensive mistakes further down.

Related decisions
Next Best Step

Insulation; the upgrade that decides everything

Take the next step