Self-Adhesive Sealing Strips: The Small Fix That Cuts Winter Heating Costs

On a January evening, the room appears to be heated, the radiator is hot and the thermostat shows the right temperature – yet you still keep your jumper on. We all know that slightly absurd moment when we turn the heating up a notch, unable to work out why the living room remains cold by the window. Often, the culprit is neither the boiler nor a complex appliance: it is a gap of just a few millimetres between the opening window and its frame. A self-adhesive sealing strip, fitted in minutes, can reduce these air leaks and stop you from heating the outdoors. It may seem like an insignificant job, but its impact can be unexpectedly noticeable.

The small air leak quietly driving up heating use

A draughty window does not necessarily rattle or show obvious signs of movement. More often, you notice it when a curtain flutters, your ankles feel cold beside the sofa, or the same draughty sensation returns every morning. The heating then constantly makes up for this subtle heat loss, especially in older homes where the window joinery has aged. A self-adhesive sealing strip will not turn an old window into a premium model, but it does narrow the gap through which cold air enters. It is only a minor detail, certainly. Yet when the same issue affects several windows, it can make a significant difference across a heating season.

In her flat in Lille, tenant Claire had got into the habit of placing a throw along her bedroom windowsill. “I thought it was normal in a 1970s block,” she says. Once she had fitted foam sealing strips to two windows and added a door draught excluder, she mainly found that she could turn the thermostat down slightly without sacrificing comfort. Depending on the condition of the property, the energy used and the number of openings involved, the saving may amount to a few tens of euros – and sometimes considerably more over a year. In an energy-hungry house heated by electricity, every avoided degree genuinely matters.

The reason is straightforward: a heating system is not only working against the outdoor cold, but also against moving air. Whenever there is an unwanted air inlet, warm air escapes and cold air replaces it. The system starts up again, time after time. It is not dramatic, but this is exactly the kind of expense that gradually becomes embedded in an energy bill. The French Agency for Ecological Transition notes that reducing the heating temperature by one degree can cut energy consumption by around 7%. Restricting draughts makes it easier to tolerate that reduction without shivering.

A five-minute DIY job with no complicated tools

Before buying anything, first locate the leak. On a cool day, slowly run your hand around the frame, or hold a light sheet of paper close to it: if it moves while the window is shut, there is probably an air leak. Next, measure the width of the gap to be filled. DIY shops sell foam, rubber and silicone sealing strips, usually on rolls costing just a few pounds. Clean and dry the fixed frame, cut the required length, peel away the backing film and stick the strip in place without stretching it. Five minutes is enough for a straightforward window.

The most common mistake is choosing the thickest strip in the belief that it will insulate better. Many people have done this, with frustrating results: the window no longer closes properly, the strip becomes misshapen, or the handle has to be forced unnecessarily. It is better to select a thickness that matches the actual gap, even if that means trying a small piece before fitting the whole strip. Let us be honest: hardly anyone really does that every day. Even so, checking the condition of seals at the start of autumn can prevent a long season of overheating your home. A flattened, loose or cracked strip no longer does its job.

The sensible approach is to deal first with the rooms where discomfort is most noticeable: the bedroom, living room, entrance hall or a corridor beside an external door. There is no need to redo everything at once. Sealing just one window properly is enough to assess the difference, particularly on waking up or during windy evenings.

“The best DIY job is often the one you forget once it is done: you no longer think about it, because you are finally warm without touching the thermostat.”

• Choose a sealing strip that is compatible with the gap between the frame and the window.
• Apply it to a clean, dry and dust-free surface.
• Test that the window closes before removing all the backing film.
• Check the bottoms of doors too, as these are often overlooked.

A few pounds today, a habit that changes winter

This DIY measure is no substitute for insulation work where walls, glazing or the roof are in very poor condition. Nevertheless, it offers a valuable advantage: it is accessible to tenants, reversible in some cases, inexpensive and immediately noticeable. Once air is no longer entering around the bottom of windows, people often stop compensating by turning up the heating. Comfort becomes steadier, less harsh and almost calmer. That feeling has value which is not always visible on an energy-use statement.

It can be useful to compare your bills before and after winter, without expecting miracles in the first week. Weather, time away from home and heating habits also affect the figures. Still, the principle remains sound: tackling small losses prevents you from continually demanding more from your heating system. A roll of sealing strip can cost less than a takeaway ordered on an exhausting evening, while quietly doing its job for several years. The same approach can then be applied to doors, roller-shutter boxes and cable or pipe penetrations.

Perhaps the most valuable part is the realisation that saving energy does not always begin with a major purchase or an intimidating renovation. Sometimes, it starts by running your hand near a window and noticing a draught you had eventually accepted. In many households, these small improvements do more than reduce spending: they restore a sense of greater control over the home. Which room in your home always feels a little too cold despite the heating?