Why Are My Windows Letting in Cold Air? 7 Things to Check

As the colder weather arrives, keeping your home warm and comfortable becomes a priority. If you notice cold draughts coming from your windows, feel a chill when sitting nearby, or find it difficult to maintain a comfortable temperature, your windows could be the cause.

Draughty windows do not always mean you need to replace them completely. In many cases, the problem could be caused by worn seals, loose fittings or minor damage that can be repaired.

At East Lothian Glass & Glazing, we help homeowners identify glazing problems and find practical solutions to improve comfort and performance. Here are seven things to check if your windows are letting in cold air.

1. Check the Window Seals

One of the most common causes of draughty windows is worn or damaged seals.

Window seals help prevent cold air from entering your home and warm air from escaping. Over time, rubber seals can deteriorate, become brittle or pull away from the frame, leaving small gaps where cold air can enter.

What to look for:

• Cracked, flattened or brittle rubber seals.
• Visible gaps around the opening window.
• Cold air entering around the edges of the frame.
• Seals that appear loose or damaged.

If the seals are worn, replacing them may help improve the window’s performance without the need for a complete replacement.

2. Inspect the Window Frames for Gaps

Even if your window glass is in good condition, gaps around the frame can allow cold air into your home.

These gaps may develop where the window frame meets the surrounding wall, particularly if the original sealing material has deteriorated or the installation has shifted over time.

What to look for:

• Cracks between the window frame and the wall.
• Gaps around the edges of the frame.
• Damaged or missing external sealant.
• Signs of dampness or water ingress around the window opening.

Small gaps may be repairable, but larger gaps or signs of water ingress should be assessed to establish the underlying cause before resealing.

3. Check That Your Windows Close Properly

If your windows do not close tightly, cold air can find its way inside even when the glass and frames appear to be in good condition.

Over time, hinges, handles and locking mechanisms can wear, become loose or fall out of alignment. This can prevent the window from closing securely against its seals.

What to look for:

• Handles that are stiff or difficult to operate.
• Windows that do not close flush with the frame.
• Loose hinges or faulty locking mechanisms.
• Gaps that remain visible when the window is closed.

A faulty handle, hinge or locking mechanism may be repairable. Having the window inspected can help determine whether an adjustment or replacement component is required.

4. Look for Damaged or Deteriorating Window Frames

Damaged frames can affect how effectively your windows keep out the cold.

uPVC frames may develop damaged seals, loose joints or other defects, while timber window frames can deteriorate through prolonged exposure to moisture and weather.

What to look for:

• Cracks or damage to the frame.
• Loose joints or separating frame sections.
• Soft, decaying or damaged timber.
• Water staining or signs of moisture around the window.

Not every damaged frame needs to be replaced. Depending on the extent of the problem, repairs may be possible. However, significant deterioration can affect the window’s structural integrity and may make replacement the more suitable long-term option.

5. Check for Condensation Between the Glass Panes

Have you noticed misting or condensation trapped inside your double-glazed windows?

Modern double glazing consists of two panes of glass separated by a sealed cavity. If the seal around the glass unit fails, moisture can enter the cavity, causing persistent misting or condensation between the panes.

This is different from condensation forming on the room-facing surface of the glass.

What to look for:

• Misting that cannot be wiped away from either accessible glass surface.
• Condensation trapped between the panes.
• Cloudy patches that remain even after cleaning.
• A noticeable deterioration in the appearance of the glass.

A failed sealed unit can affect thermal performance. In many cases, the glass unit can be replaced without replacing the entire window frame, provided the existing frame remains in suitable condition.

East Lothian Glass & Glazing can help you explore replacement glazing options for your home.

6. Consider Whether Your Existing Glazing Is Suitable

Sometimes, cold windows are not caused by a fault at all. Older or less thermally efficient glazing can leave the glass surface noticeably colder during winter.

Single glazing and older double-glazed units may provide less insulation than modern glazing systems. When warm indoor air comes into contact with a cold glass surface, the area around the window can feel uncomfortable, even when there is no actual draught.

What to consider:

• Whether your windows are single or double glazed.
• The age and condition of the existing glazing.
• Whether condensation frequently forms on the room-facing glass.
• Whether rooms near the windows feel colder than the rest of the house.

Depending on your property and the condition of your windows, upgrading the glazing or installing replacement windows may improve comfort and thermal performance.

The most appropriate solution will depend on the existing frame, the glazing specification and your home’s requirements.

7. Check for Draughts Around Window Openings and Sills

The final area to investigate is around the window sill and the junction between the frame and the surrounding structure.

Cold air can sometimes enter through gaps beneath the sill, around the window opening or through deteriorated sealing materials. These issues can be mistaken for a problem with the glass itself.

What to look for:

• Cold air that seems to come from beneath the sill.
• Cracked or missing sealant around the window.
• Loose or damaged trim.
• Gaps where the window meets the surrounding wall.

A careful inspection can help identify whether the problem relates to the window, the installation or the surrounding building fabric. This is important because replacing the glass alone will not resolve draughts caused by gaps elsewhere.

Should You Repair Your Windows or Replace Them?

The right solution will depend on the cause of the problem and the overall condition of your windows.

Repairs may be suitable if:

• The window seals have deteriorated.
• The handles, hinges or locking mechanisms are faulty.
• The frame is generally in good condition.
• A double-glazed unit has failed but the existing frame remains sound.

Replacement may be worth considering if:

• The frames are significantly damaged or deteriorated.
• Multiple components are failing.
• The windows are no longer performing as required.
• Repairing the existing windows would not provide a satisfactory long-term solution.

A professional assessment can help you understand your options before committing to a larger investment.

How East Lothian Glass & Glazing Can Help

At East Lothian Glass & Glazing, we understand how frustrating draughty windows can be, particularly during the colder months.

Our team can help you explore suitable options for your property.

If you live in East Lothian or the surrounding area’s and have noticed cold air coming through your windows, we are here to help.

Don’t let draughty windows make your home uncomfortable this winter.

Contact East Lothian Glass & Glazing today to discuss your window concerns and request a quote.