Condensation and Moisture on Windows – Causes and Solutions
Moisture on windows can have three completely different causes, each requiring a different solution. Identifying which type you have is the key to fixing it correctly.
Moisture or condensation on windows concerns many homeowners, particularly during the heating season. Before assuming your windows are faulty, it is essential to know that condensation has three distinct causes — each requiring a different solution.
Three Types of Window Condensation
On the inner surface (room side): classic sign of high indoor humidity and insufficient ventilation. The window is working correctly — the indoor environment needs correction. On the outer surface: morning dew on the outside is a paradoxically good sign — it means the window is very well insulated, keeping the outer pane cool enough to collect dew. No action needed. Between the panes: fogging inside the sealed unit means the perimeter seal has failed. This cannot be fixed without replacing the glass unit.
Inner Surface Condensation – A Ventilation Problem
Modern PVC windows are very airtight — their thermal advantage means natural air infiltration through gaps is eliminated. When older leaky windows are replaced with sealed PVC units, gravity ventilation may no longer work correctly, causing humidity to rise. The solution is improved ventilation: regular airing (10 minutes of intensive through-ventilation daily), checking ventilation grille clearance, and where the problem is persistent, installing trickle vents. Trickle vents provide controlled fresh air intake without heat loss, and hygro-sensitive models automatically increase airflow when indoor humidity rises.
Between-Pane Condensation – Glass Unit Replacement
Fogging between panes cannot be resolved by ventilation improvement or window adjustment. The glass unit seal has failed and the unit must be replaced. In most cases, only the sealed unit is replaced — the frame stays in place. Cost from 180 PLN. Early signs of seal failure include faint morning mist that clears by midday; later stages show permanent fogging and water droplets. Do not delay — the problem worsens over time and can cause mould growth on the frame. Contact Naprawa Okna 24 window repair for a free on-site diagnosis.
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Frequently Asked Questions
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.