Condensation Between Window Panes

If fog, mist or droplets are inside the sealed space between the panes and cannot be wiped from either the room side or the exterior, this indicates a problem with the seal of the insulating glazing unit.

It is important first to establish which surface the moisture is on. Condensation on the room-side or exterior surface has different causes from moisture genuinely trapped between the panes.

What does condensation between panes mean?

An insulating glazing unit consists of at least two panes separated by a sealed cavity. Its edge-seal system limits water-vapour penetration into that cavity. If the seal no longer performs this function, moisture can enter the space between the panes and become visible as fog, mist or droplets.

This symptom concerns the glazing unit itself and does not automatically mean the whole window has failed. The frame and sash may remain serviceable.

How can you distinguish between-pane condensation from surface condensation?

• Between the panes – the mark cannot be reached or wiped from either accessible side of the glass.
• On the room-side surface – moisture is on an accessible inner surface and can be associated with factors including surface temperature, indoor humidity and ventilation.
• On the exterior surface – temporary condensation can occur under suitable temperature and humidity conditions and does not by itself indicate glazing-unit seal failure.

Identifying where the condensation sits matters because moisture genuinely inside the sealed cavity is the symptom associated with loss of glazing-unit seal integrity.

Why can moisture enter a glazing unit?

Insulating glazing units use an edge-seal system designed to limit water-vapour penetration into the cavity between the panes. If that system ceases to perform as intended, moisture can enter the cavity.

We do not determine the cause from the age of the window alone. The condition of a unit can depend on factors including manufacture, installation, service conditions and possible damage, so the individual case needs assessment.

Can a misted glazing unit be cleaned?

If moisture is inside the factory-sealed cavity, ordinary cleaning, wiping or ventilating the room will not remove it. It is not contamination on an accessible glass surface.

Once loss of seal integrity is confirmed, we select the appropriate solution for the construction and condition of the unit. In a typical service situation this means replacing the affected glazing unit without replacing the whole window.

How do we diagnose the problem?

We check whether the mark is genuinely between the panes or on one of the accessible surfaces. We inspect the glazing unit and its installation and establish the parameters needed to select the appropriate solution.

If the assessment confirms a glazing-unit problem for which replacement is appropriate, the full scope of that service is described on our Glass Unit Replacement page.

Does the whole window need replacing?

Not because of between-pane condensation alone. If the frame and sash are in suitable condition, a glazing-unit problem can be addressed without replacing the entire window. We determine the work required after assessing the particular window and unit.

What can you check yourself?

Check both accessible glass surfaces. If moisture can be wiped from either side, it is not inside the glazing unit. If visible mist or droplets remain between the panes and cannot be reached from either side, the unit's seal integrity should be checked.

There is no need to remove glazing beads or dismantle the sash for this initial check.

What solution may be required?

After confirming loss of seal integrity, a new glazing unit suitable for the existing window is commonly selected. Its specification depends on the construction and dimensions and on requirements such as thermal performance, safety or other glass properties.

The symptom alone is not enough to specify a particular unit build-up or gas fill. The appropriate solution is selected after measurement and identification of the existing glazing.

Brands we work with

Regardless of the window or door manufacturer, we most often service wear-and-tear components that naturally degrade over time.

• VEKA, Salamander, Aluplast, Rehau – European PVC systems, among the most commonly found in Polish residential construction.
• Drutex, Oknoplast, MS Więcbork – Polish manufacturers found in newer residential developments.
• Schüco, Aluprof – aluminium windows and HST patio doors used in modern construction.
• Roto, Winkhaus, Maco, Siegenia – manufacturers of hardware and multi-point locking systems.
• Velux, Fakro – roof windows commonly installed in detached houses.

We use original spare parts or high-quality replacements — depending on the manufacturer and component availability.

How does our service work?

The service process is simple and transparent — six steps from first contact to warranty:

• Contact – fill in a short form or call us. We call back within approximately 15 minutes.
• Free on-site diagnostics – a technician arrives at the agreed time and assesses the condition on site.
• We explain the cause – we show you exactly what needs to be repaired.
• We present the cost – after diagnostics we provide an exact quote. No hidden fees.
• We carry out the repair – after your approval we complete the work, most often during the same visit.
• You verify the result – we test the outcome together. You receive a service report, a warranty on the work performed, and the manufacturer's warranty on original parts.

Where do we diagnose condensation between panes?

We serve Warsaw, Krakow, Katowice and other regions covered by our service. You can check the current coverage on our Cities page.

How much does it cost to solve the problem?

The cost depends on the dimensions and specification of the required glazing unit and the work involved. Diagnostics and the technician call-out for assessment are free. Before paid work begins, we provide a quote for approval.

You can find indicative prices on our pricing page.