Is Your Home Leaking £1 Coins Through Tiny Gaps?

Before buying another heater, find out where the warm air from the one you’ve already got is escaping.

There is something particularly irritating about sitting in a heated room and feeling a cold draught around your ankles.

The heating is on. The thermostat seems satisfied. Yet you are considering another jumper, a higher temperature setting or perhaps a small electric heater beside the chair.

Before reaching for the thermostat, try reaching for a notebook.

Your home may have a collection of small, unwanted air leaks: a poorly fitting door, a tired window seal, a letterbox that never quite closes or a loft hatch with a gap around its edge.

None looks especially dramatic. Together, they deserve investigation.

This autumn, turn draught-proofing into a little household detective work. The question is simple:

Where is air moving when you haven’t deliberately invited it to?

The mystery: why is a heated room still uncomfortable?

A room’s temperature tells only part of the comfort story.

Moving air carries heat away from your skin. Cold surfaces can also make you feel chilly, even when the air around you is reasonably warm. That means a cold feeling near a window does not automatically prove that outside air is coming through a gap.

Sometimes there is a leak. Sometimes room air is cooling against the glass and sinking towards the floor.

The distinction matters. Replacing a window seal will help with an air leak; it will not transform the insulating performance of the glass.

Good detective work starts with evidence, rather than buying the first product labelled “energy saving”.

Assemble your draught detective kit

You do not need an expensive instrument to begin. Gather:

• A notebook or your phone.
• A torch.
• A tape measure.
• A narrow strip of lightweight tissue.
• A pencil for marking locations on a simple room sketch.

Choose a cool, breezy day, with external doors and windows closed as they normally would be when the heating is on. Keep the home’s ventilation operating normally.

Slowly move your hand around suspect joints. Hold the tissue near a gap and watch for movement, keeping your own breathing away from it. Look for daylight around closed external doors.

A fluttering tissue is a clue, rather than a precise measurement. Check several nearby positions before deciding where the air is coming from.

Use tissue rather than a candle or incense stick: you can investigate without introducing a flame or smoke.

Give each discovery one of three labels:

Fix: a clear, accidental gap.

Investigate: something damaged, inaccessible or of uncertain purpose.

Keep clear: an intentional ventilation opening.

That third category is essential.

Case one: the front door with several escape routes

A front door can have more than one draught problem. Examine the perimeter, threshold, letterbox and keyhole separately.

Suitable remedies include correctly sized perimeter seals, a threshold brush or flap, a letterbox brush and a purpose-made keyhole cover. The door must still close and lock easily. Energy Saving Trust

Imagine a hallway where the family regularly turns up the heating because the stairs feel cold. The obvious suspect might be the radiator. But the detective exercise reveals that the letterbox flap stays partly open after each delivery.

That is a useful discovery: a specific fault with a specific remedy.

Before ordering anything, measure it. A replacement that nearly fits can leave you with almost exactly the same problem.

Case two: the window that needs attention, not immediate replacement

Inspect the join between the opening window and its frame, then the junction between the frame and wall.

Look for damaged seals, failed sealant or a window that no longer closes evenly.

Opening windows need seals matched to the gap; sliding sash windows generally need suitable brush seals. A strip that is too thick can prevent proper closure, while one that is too thin leaves the leak. Energy Saving Trust

For older properties, there can be considerable value in repairing and draught-proofing original windows. Historic England identifies this as a relatively inexpensive, minimally intrusive improvement, with secondary glazing another option where appropriate. Historic England

The practical lesson is to identify the fault before choosing the scale of the solution.

A failed seal and an entire failed window are different purchasing decisions.

Case three: the forgotten hatch above your head

The loft hatch is easy to overlook. We walk beneath it every day without thinking of it as part of the boundary between the heated house and a colder space.

Check whether it sits squarely and closes firmly.

A suitable perimeter seal can reduce leakage, while insulation on the hatch itself addresses heat passing through the panel. These are complementary jobs. The Centre for Sustainable Energy recommends considering both. Centre for Sustainable Energy

Seal the hatch, while preserving the roof space’s required ventilation.

Keep the inspection manageable. You do not need to venture across an unboarded loft to decide that a hatch needs closer attention.

Case four: the holes hidden behind ordinary household objects

Pipe penetrations are often less conspicuous than doors and windows.

Look where accessible water or heating pipes pass through external walls or floors, including beneath sinks and behind removable cupboard panels.

For ordinary small gaps, an appropriate sealant or filler may be suitable. Floorboard and skirting gaps can also need flexible materials that accommodate movement. Centre for Sustainable Energy

However, identifying the hole comes before filling it.

A gap around a water pipe is different from an opening associated with a boiler flue, electrical equipment or a construction detail requiring a particular fire-resistant seal. If its function is unclear, put it on the “investigate” list and seek suitable advice.

A tube of sealant is useful. It is not a diagnosis.

Case five: the fireplace that is decorative but still connected to outdoors

An unused open fireplace deserves attention.

A chimney can remain a route for air movement even when nobody has lit a fire for years. Purpose-made removable draught excluders can help, but the chimney must retain appropriate ventilation to avoid damp problems. Historic England specifically advises against completely sealing the flue. Historic England

Any removable excluder must come out before a fire is lit. Energy Saving Trust

Do not improvise by stuffing the opening with old cushions or packaging. If the chimney’s condition, connections or future use are uncertain, ask a chimney professional.

This is one suspect that deserves a careful interview.

The crucial distinction: draughts and ventilation

Here is the rule that should sit at the top of your notebook:

Reduce unwanted leakage while maintaining the ventilation your home needs.

Ventilation removes moisture and indoor pollutants. Cooking, washing, showering and breathing all add moisture to indoor air; inadequate ventilation can allow it to accumulate and contribute to condensation and mould. GOV.UK

Keep these clear and functioning:

• Window trickle vents and purpose-provided wall vents.
• Kitchen and bathroom extraction.
• Airbricks ventilating suspended timber floors.
• Combustion air supplies and appliance flues.

Internal door undercuts may also provide necessary airflow between rooms. They should not automatically be treated as faults to seal. Energy Saving Trust

In some older homes, accidental gaps may be providing much of the existing ventilation. Extensive sealing therefore needs a ventilation assessment, particularly where there is already condensation, mould or poor air quality. Government guidance for England makes clear that energy improvements should not worsen ventilation. GOV.UK

If an intentional vent feels excessively draughty, investigate its design and the wider ventilation arrangement with a competent professional.

My perspective: impressive technology still needs the basics

At home, I have invested in solar panels, battery storage, a heat pump and insulation. It is easy to become interested in the larger pieces of equipment: how much electricity we generate, when the batteries charge and how efficiently the heating operates.

Yet the basic question remains:

How well does the house retain the warmth we put into it?

That is why this detective approach appeals to me. It brings household energy back to something tangible: observe, identify, make a suitable change and check the result.

As a teacher, I also like the opportunity for children to take part. They can draw a floor plan, record clues and help compare the same location before and after a repair. Adults can handle the fitting and any work requiring tools or access equipment.

It becomes a small investigation with a useful outcome.

Are £1 coins really escaping?

The title is a metaphor. A gap does not have a fixed price attached to it.

Its effect depends on its size, exposure to wind, indoor and outdoor temperatures, heating pattern and the rest of the building.

Avoid promises that a particular strip of foam will save every household the same amount.

Instead, assess three things:

Comfort: has the unwanted air movement reduced?

Function: does the door, window or hatch still work properly?

Value: was the improvement worth its cost?

For illustration only, suppose a repair costs £20 and eventually saves £10 a year. Its simple payback would be two years. Those are example figures, not a forecast for your home.

Bills are also affected by weather and heating habits, so a single cheaper day does not prove the size of a saving.

Your weekend challenge: solve three small mysteries

Rather than attempting the entire house at once, choose three confirmed problems.

Your investigation sheet could look like this:

Location	Evidence	Next action	Result
Front-door letterbox	Flap stays partly open	Check and repair or replace	Recheck after next delivery
Bedroom window	Tissue moves at one closing edge	Inspect seal and alignment	Repeat test in similar weather
Loft hatch	Uneven fit around frame	Assess closure, seal and insulation	Check operation and leakage
Bathroom wall vent	Purpose-provided opening	Keep clear	No sealing required

Photograph each problem before changing anything. Keep product details and measurements together.

Afterwards, revisit your list. A repair that worked is worth recording; one that failed is evidence that the original diagnosis or chosen material needs another look.

If you rent, report defective fittings to your landlord and agree alterations before making permanent changes.

Before you buy more heat, investigate the gaps

Draught-proofing rarely produces the excitement of a new heating system. There is no impressive display on a letterbox brush and very little glamour in a well-fitting loft hatch.

But small maintenance jobs can make a home more comfortable and reduce avoidable heating demand.

The aim is a warmer home with healthy, deliberate ventilation.

So, before buying another heater, take a slow walk around the one you already live in.

A notebook, a strip of tissue and a little curiosity might reveal where your next useful home improvement should begin.