VELUX Window Letting in Cold Air? Causes & Fixes

During colder weather, homeowners often become much more aware of their roof windows. A room that felt perfectly comfortable during summer may suddenly seem cooler around the VELUX window, leading to an obvious question: is cold air getting in?

Sometimes it is. But a cold sensation around a roof window is not proof of an air leak. Understanding the difference between a genuine draught, normal ventilation and cold air movement across the glazing can prevent unnecessary repairs and help identify problems that really do need attention.

Why does my VELUX window feel draughty?

There are several possible explanations. Some relate to normal operation, while others can indicate maintenance or repair is required.

Common possibilities include:

normal airflow through the ventilation system
cold air moving down the surface of the glazing
worn or damaged seals
the sash not closing correctly
an operating or locking problem
poor insulation around the window opening
age-related deterioration of the roof window

First question: can you actually feel moving air?

There is an important difference between an area simply feeling colder and being able to identify a stream of air entering around a closed window. That distinction can help narrow down the likely cause.

Cold glass can feel like a draught

This is something that can easily be misunderstood, particularly with older glazing.

During cold weather, the inside surface of a roof window can be cooler than the surrounding walls. Indoor air next to that glass cools, becomes denser and moves downwards.

That movement of cooler air can sometimes feel like a draught even though outside air is not actually passing through the window.

Cold downdraught

Indoor air is cooled by the glazing and moves downwards. The window can feel draughty even though there is no obvious gap to the outside.

Actual air leakage

Outside air is physically entering through or around part of the closed roof window or surrounding installation.

Could it simply be the VELUX ventilation system?

VELUX roof windows are designed to provide ventilation. Depending on the model, fresh air can be introduced through a ventilation flap or control bar while the main window remains closed.

In colder weather, that incoming air will naturally feel cold.

This is different from an uncontrolled draught caused by deterioration or a window that is not sealing correctly.

How do I know if the seals are worn?

Window seals are exposed to years of compression, temperature changes and everyday use. Over time they may become worn, damaged or less effective.

Possible signs include a localised draught around part of the closed sash, increased external noise, whistling in windy weather or a change in how securely the window appears to close.

Our guide to a VELUX window making a whistling noise looks more closely at the connection between wind, airflow and seals.

Does a draught mean I need new VELUX seals?

Not automatically.

It is tempting to assume that every draught is caused by a failed seal, but the sash may not be closing correctly or air may be moving through another part of the installation.

Replacing a seal without identifying the source of the draught can therefore fail to solve the problem.

Could the VELUX window be slightly open?

A window does not need to look obviously open to allow noticeable airflow.

If the sash is not seating correctly into the frame, or the locking mechanism is not pulling it into its normal closed position, a small gap may remain.

Look for changes such as:

the window becoming harder to close
the handle or control bar feeling different
one side appearing to close before the other
a visible uneven gap around the sash
new rattling or movement during windy weather
the window no longer feeling secure when closed

If the mechanism is stiff, do not simply force the window closed. Read our guide to a stiff VELUX window that is difficult to open.

Can poor insulation around a roof window cause cold spots?

Yes. The comfort of a roof window installation depends on more than the glass and frame.

The junction between the window and the surrounding roof also needs to be properly insulated. If insulation around the opening is inadequate or has been disturbed, surfaces around the window can become colder.

That can create uncomfortable cold areas and may also increase the likelihood of condensation in certain conditions.

The coldest point may not identify the source

Air can travel through hidden gaps before becoming noticeable inside the room. Feeling cold air beside the frame does not always mean the visible frame or seal is where the problem begins.

Why is my old VELUX window colder than a newer one?

Roof window technology has changed considerably over time. An older window may have glazing and thermal performance that is noticeably different from a modern replacement.

Even if an older window remains functional and weatherproof, the inside surface of its glazing may become colder during winter than that of a more modern unit.

This can increase the sensation of cold near the window without necessarily indicating that it is physically leaking air.

Can failed glazing make a VELUX window feel cold?

Problems with the glazing unit can affect the performance of the window. One of the most obvious signs of a failed sealed glazing unit is persistent misting or moisture trapped between the panes.

If your window is both unusually cold and visibly misted between the panes, the glazing deserves closer inspection.

Depending on the age and condition of the overall window, the appropriate solution may involve the glazing or potentially a complete replacement roof window.

Why is condensation appearing around the cold window?

Condensation occurs when moisture in indoor air meets a surface cold enough for water vapour to condense.

Roof window glazing is often one of the colder surfaces in a room during winter, so condensation can become more noticeable when outdoor temperatures fall.

That does not necessarily mean the window is leaking.

If condensation is part of the problem, see our guide on how to reduce condensation on VELUX windows.

Could the cold air be coming from the roof rather than the window?

Potentially. A VELUX window forms part of a larger roof construction.

The surrounding roof, insulation, internal lining and installation details can all affect thermal comfort around the opening.

This is one reason diagnosing a draught solely by touching the inside frame can be misleading.

Can I test a draught myself?

You can make some useful observations without dismantling anything.

When the weather is cold or windy, note:

where you can feel the coldest area
whether you can feel actual moving air
whether the ventilation flap is open
whether the window is fully closed
whether the draught changes with wind direction
whether the window whistles at the same time
whether the glass is misted between the panes
whether there is condensation on the room-side glass

These details are much more useful than simply reporting that the window "feels cold".

Should I seal the window with silicone?

No, not without knowing what is causing the draught.

Applying silicone, expanding foam or another sealant to visible gaps can interfere with ventilation, drainage or moving parts and may simply hide the symptom.

Roof windows are designed systems. A problem should be diagnosed before material is added around them.

What about temporary draught-proofing tape?

Temporary products may appear attractive during winter, but care is needed. Covering ventilation openings or sticking materials to seals and moving components can create other problems.

If a window is producing an obvious uncontrolled draught, finding out why is a better long-term approach than continually covering it.

Can AR Windows repair a draughty VELUX window?

AR Windows provides specialist VELUX repairs and VELUX maintenance.

If the problem relates to a serviceable component and the window remains in suitable condition, repair or maintenance may be appropriate.

The aim is not to replace a complete window unnecessarily. Equally, repeatedly repairing an ageing roof window with several unrelated problems may no longer be the most economical solution.

Repair may make sense

The window is otherwise sound and the draught can be traced to a suitable repairable or serviceable component.

Replacement may make sense

The window is older and the draught is accompanied by poor glazing, deteriorating timber, repeated faults or other significant age-related problems.

When should an older VELUX window be replaced?

There is no single age at which every VELUX window must be replaced. Condition and performance are more useful than age alone.

Replacement becomes more worth considering when several problems occur together:

persistent draughts
failed or misted glazing
damaged or deteriorating timber
repeated leaks
stiff or worn mechanisms
poor thermal comfort
multiple repairs becoming necessary

A new roof window can address several of these issues in one project rather than continuing to replace individual components on an ageing unit.

Can regular servicing help?

Routine servicing gives an opportunity to inspect the condition and operation of a roof window and identify deterioration before it becomes more disruptive.

It cannot stop a window ageing, but maintenance can help keep serviceable components working correctly and highlight when further repair should be considered.

AR Windows offers one-off maintenance as well as planned care through our Annual Service Contract.

What should I send AR Windows?

If you contact us about a cold or draughty roof window, provide as much useful information as you safely can.

Ideally send:

a photograph of the complete window
a photograph of the VELUX product code
the approximate age if known
where you feel the draught or cold
whether it only happens in windy weather
whether the window closes normally
whether it also whistles or rattles
whether the glazing is misted
details of condensation or previous leaks

Do not climb onto the roof or lean outside the window to investigate it yourself.

Cold or draughty VELUX window?

Send AR Windows your VELUX product code, photographs and details of where you feel the cold air. We can help determine whether maintenance, repair or replacement is likely to be appropriate.

Contact AR Windows View VELUX repairs

Final thoughts

If your VELUX window feels cold, do not immediately assume that outside air is leaking through it. Cold glazing, natural air movement and the window's ventilation system can all create sensations that feel similar to a draught.

A strong or newly developed draught around a fully closed window is different. Worn seals, closing problems, insulation or the wider installation may need to be investigated.

Identifying which of these is happening is the key to deciding whether your VELUX window simply needs attention, can be repaired or has reached the point where replacement offers the better long-term solution.

FAQs

Draughty VELUX window FAQs

Why can I feel cold air from my VELUX window?

The sensation may be caused by normal ventilation, cool air moving down the surface of cold glazing or genuine air leakage. If you can identify a strong draught around a fully closed window, it is worth investigating.

Does a draught mean my VELUX seals need replacing?

Not necessarily. Worn seals are one possible cause, but the sash may not be closing correctly or the airflow may originate elsewhere around the installation.

Why does my VELUX window feel colder in winter?

The glazing becomes colder as outdoor temperatures fall. Indoor air can cool against the glass and move downwards, creating a cold downdraught even when the window itself is properly sealed.

Should I put silicone around a draughty VELUX window?

Not without identifying the cause first. Applying sealant in the wrong place can interfere with ventilation, drainage or moving components and may not address the source of the problem.

Can an old VELUX window be made less draughty?

It depends on why it feels draughty and the condition of the window. Some problems may be serviceable or repairable. Where several age-related faults are present, replacement may provide the better long-term solution.

Can AR Windows inspect a draughty VELUX window?

Yes. AR Windows provides VELUX maintenance and repair services and can advise whether a particular problem is suitable for repair or whether replacement should be considered.

Why is my VELUX window letting in cold air?