When you’re relaxing at home on a chilly evening, nothing is more frustrating than feeling a sudden cold draught sneaking in around your windows. Many Dorset homeowners experience this, particularly in older properties or when double glazing hasn’t been serviced for years.
But what do these draughts or cold spots actually mean? Are they just a nuisance, or could they be signs of a bigger problem — like failed window seals? In this post, we’ll break down what window seals are, why they fail, and what your options are if you’re noticing unwanted chills in your home.
To understand the problem, it helps to know how double glazed windows work. A standard double-glazed unit consists of two panes of glass with a sealed gap in between. That gap is usually filled with air or an insulating gas such as argon, which reduces heat transfer and keeps your home warmer in winter and cooler in summer.
The window seals are the all-important component that:
Hold the panes together and keep the gas or air trapped inside.
Prevent outside air from entering your home.
Stop warm indoor air from escaping into the cold outdoors.
Block moisture intrusion that could lead to condensation, mould, or damp.
In short, without working seals, your windows can’t perform their job. Your heating system has to work harder, your rooms become less comfortable, and you may start to notice condensation between the panes.
One of the most common symptoms of seal failure is a draughty window. You might feel a chill on your face or hands when you sit near a particular window, or notice one area of the room always feels colder than the rest.
Why does this happen?
Perimeter seal failure – If the rubber or silicone sealant around the glass has cracked, shrunk, or come loose, it creates tiny gaps where cold air can enter.
Glazing unit failure – When the internal seal between the two panes of glass is compromised, insulating gas escapes, reducing thermal efficiency. The glass feels colder, which creates the sensation of a “cold spot.”
Frame or installation issues – Sometimes it’s not the glazing at fault, but poor installation or shifting frames that create gaps where air leaks through.
While not every draught is caused by failed seals, draughts and cold patches are a strong indicator that your windows need a closer inspection.
It can be tempting to live with a minor draught, especially if it’s just in one room. However, ignoring failed window seals almost always leads to bigger problems:
Rising heating costs – Energy efficiency is one of the biggest selling points of double glazing. With broken seals, that efficiency is lost, costing you money every month.
Reduced comfort – Even with the heating turned up, you may find certain rooms never get truly warm. This can be especially uncomfortable in bedrooms during winter.
Moisture and mould problems – Moisture entering through failed seals encourages condensation. Over time, this can cause mould growth, which isn’t just unsightly but also harmful to health.
Further window damage – Once seals break down, the entire window unit can deteriorate more quickly, leading to full replacement being necessary sooner than expected.
Simply put, acting early saves money, energy, and stress.
The good news is that not every draughty window requires a full replacement. Depending on the condition of your windows, repairs can often restore comfort and efficiency at a fraction of the cost of new windows.
Seal replacement: If the perimeter seal has cracked or shrunk, resealing the unit can often resolve the draught without touching the glass.
Glazing unit replacement: If condensation is trapped inside or the gas has escaped, swapping out just the double-glazed unit (while keeping the existing frames) is usually a cost-effective fix.
Minor adjustments: Sometimes, loose hinges, warped frames, or poor fitting can cause draughts. Adjusting or repairing these areas can solve the issue.
In some cases, full window replacement is unavoidable — especially if:
The frames are rotting, warped, or structurally unsound.
Multiple units have failed, making piecemeal repairs less cost-effective.
The windows are very old and lack modern efficiency standards.
Most Dorset homeowners are relieved to hear that repairs are often the first port of call, and only if windows are in very poor condition is full replacement necessary.
Living with draughts or cold spots is not only uncomfortable, it’s also costing you money. Whether you’re in Bournemouth, Poole, Christchurch, Weymouth, or Dorchester, failed window seals are a common problem — but one that can be fixed.
By acting quickly and arranging for a repair, you’ll restore warmth, save on energy bills, and prolong the lifespan of your double glazing.
If you’ve noticed draughts or cold spots near your windows, chances are your seals need attention. Don’t wait until the problem gets worse — get a professional repair and enjoy a warmer, more efficient home.