Glass Unit Replacement – When Is It Needed and What Does It Cost?
Permanently fogged glass, moisture between panes or frost on the inside of the unit – these are signs of a failed glass unit seal. Learn what a glass unit is, how to tell failed seals from normal condensation, and what replacement costs.
Fogged glass that doesn't clear even after several sunny days, moisture trapped between the panes, or visible droplets inside the unit – this is not dirt or temporary condensation. It is a sign of a failed glass unit seal. The problem is confined to the sealed space between the panes and cannot be fixed with a cloth or window cleaner. The only effective solution is glass unit replacement.
What a Glass Unit (Insulating Glass Unit) Is
A glass unit (IGU – Insulating Glass Unit, or in Polish: pakiet szybowy / szyba zespolona) consists of two or three glass panes bonded with a spacer bar and sealed at the edges. The cavity between the panes is filled with dry air or a noble gas – usually argon or krypton – which improves the thermal insulation of the window. The seal comprises two layers: a flexible butyl inner seal and an outer sealant (polysulphide or silicone). A desiccant (silica gel) inside the spacer bar absorbs any residual moisture in the cavity.
Symptoms of a Failed Seal – Normal Condensation vs. Failed Unit
External condensation (normal): Water vapour condenses on the outer pane surface in humid conditions and disappears within hours. Can be wiped from outside. No repair needed.
Internal surface condensation near the frame (warning sign): Forms on the room-side pane surface, usually in winter, and typically disappears in warmer seasons. Often caused by insufficient ventilation or over-tight seal rather than a failed unit.
Failed glass unit (replacement required): Fog or droplets are visible between the panes, in the sealed cavity. Cannot be wiped away from either surface. Does not clear after days of sunshine. May leave mineral deposits or streaks on the inner glass surfaces. This is a definitive diagnosis: the edge seal has failed, moisture has entered the cavity, and the desiccant in the spacer bar is saturated.
Unit Replacement vs. Full Window Replacement
Glass unit replacement means the frame (PVC, aluminium or timber) stays in place – only the sealed glass unit is replaced. A technician removes the old unit from the glazing bead, inserts a new one made to measure, and reseals. Full window replacement is only necessary when the frame itself is damaged, deformed or so old that replacing the unit alone would be a half-measure.
What Replacement Costs
Approximate prices including labour: small window (up to 0.5 m²) from 150–300 PLN; standard single-sash window (0.5–1.5 m²) from 250–500 PLN; double-sash or balcony door (1.5–3 m²) from 400–900 PLN; large terrace or sliding window (above 3 m²) from 700–1 500 PLN+. An accurate quote requires on-site measurement. Non-standard shapes (triangles, arcs) and three-pane units cost more.
How Long Replacement Takes
Replacing one glass unit takes 30–90 minutes on site. The window is ready for normal use after 24 hours (sealant curing time). Custom-sized units typically take 5–10 business days to manufacture and deliver.
Frequently Asked Questions
When is glass unit replacement necessary?
Replacement is required when there is permanent fog, moisture or droplets visible between the panes – in the sealed cavity that cannot be accessed from either surface. If fogging clears within hours or is only on the outer surface, the unit has not failed.
Is replacing the glass the same as replacing the glass unit?
Colloquially yes, but technically no. In a PVC window the entire sealed unit – spacer bar, gas filling and edge sealant – is always replaced as a whole. You cannot replace just the glass pane without the spacer and sealing system.
How long does glass unit replacement take?
30–90 minutes per unit on site, plus 24 hours for sealant to cure. Custom orders require 5–10 business days. Contact Naprawa Okna 24 window repair for a free on-site quote.
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Everything you need to know about our window and door repair services
Yes, the initial diagnostics and our technician's visit to assess the work are completely free. No hidden costs and no obligations. If you decide to proceed with the service, the technician will provide a clear quote on site, explain all the details, and if needed – can start work immediately and complete the repair during the same visit.
Absolutely! We provide a warranty for both the services performed and the materials used – in accordance with applicable regulations.
We cover all of Poland, with a particular focus on major metropolitan areas: Warsaw and surroundings, Kraków and Małopolska, Łódź area, Poznań and surroundings, Katowice and all of Silesia (Sosnowiec, Gliwice, Chorzów, Bytom, Zabrze, Tychy and 30+ cities). Call us – we'll call back within 15 minutes to arrange a visit.
The price depends on the type of window, the nature of the issue, and the materials needed. Upon arrival, the technician will provide an exact quote on site with no hidden fees, and you decide whether you want to proceed with the work.
Booking a free diagnostics is very simple. Just call our contact number or fill in the registration form – either way it only takes a few minutes.
In most cases, repair is sufficient: replacing seals or hardware, sealing, adjustment, cleaning and lubricating the mechanisms. This is a much cheaper solution than installing new windows.
Repair is cheaper because you don't need to buy a new window, remove the old one, dispose of it, or carry out finishing work after installing a new unit. Repair saves both time and money, being a significantly more cost-effective solution.
We service windows from all major manufacturers, including: Rehau, Veka, KBE, Schuco, Salamander, Aluplast and many others. Our technicians undergo training on the specific mechanisms of each manufacturer.
Yes, we accept all major payment cards, bank transfers and cash. Payment is made after the work is completed.
Yes, we provide services all year round. During winter, we carry out window servicing using special methods to avoid cooling down the rooms and ensure maximum comfort.
Balcony door adjustment for PVC or aluminium doors starts from 80 zł. It includes precise 3D adjustment of hinges and fittings, eliminating sagging, draughts and closing issues. Free on-site diagnostics – the technician will quote on arrival.
Yes. We specialise in sliding and HST terrace door service for all major systems: Schüco ASS 70/77, Aluprof MB-77 HS, Aliplast Imperial. We replace load rollers, repair tracks, adjust closing pressure and service drive mechanisms. From 150 zł.
A window ventilator (trickle vent) is a ventilation device fitted in or above a window frame, providing a constant supply of fresh air without opening the window. Since 2021 (Polish building regulations WT 2021), ventilators are mandatory in new buildings. We install pressure-controlled, humidity-sensitive and acoustic ventilators – from 80 zł each.
After your enquiry we call back within 15 minutes and agree a time. In most cities (Warsaw, Katowice, Łódź, Poznań, Kraków) a technician arrives the same or next working day. For urgent cases such as a fallen hinge or jammed door, we aim to arrive within a few hours.