Roof Windows for the Home – What to Consider When Purchasing Them?
Windows are the showcase and "eyes" of every home. Skillfully integrated into the building's structure, they determine its aesthetics and give it a unique character. At the same time, they are responsible for thermal comfort, proper lighting of the attic, and the safety of the household members. However, purchasing windows is a significant challenge for many investors. The products offered on the Polish market differ significantly from each other – and not just in price.
What should you consider when choosing roof windows so that they serve reliably for many years in the capricious Polish climate? How to select joinery that is not only aesthetic but, above all, functional and energy-efficient? You will find the answers in the article below.
First – Material of Roof Windows
Roof windows are most commonly made from three types of materials – plastic (PVC), wood, and aluminum. Each of them has slightly different properties and purposes.
PVC (Plastic): These are the most popular, extremely durable, and maintenance-free roof windows. They usually come in classic white or in veneers that imitate wood. Profiles made of high-impact polyvinyl chloride are 100% moisture-resistant. A key advantage of PVC windows is their excellent thermal insulation and the fact that (aside from standard cleaning) they require no additional maintenance. They are the absolute number one choice for bathrooms, laundries, and kitchens in the attic.
Wood: Roof windows made from wood are valued mainly for their unique aesthetic qualities. Their beautiful and elegant appearance brings warmth and a traditional character to the interior. They are made from high-quality wood (coniferous and exotic species), protected during production with varnish stains. However, it should be remembered that wood – although beautiful – requires regular maintenance and refreshing of the paint coating every few years.
Aluminum: Windows with aluminum profiles or modern combinations of wood with aluminum external covers are gaining popularity. They blend perfectly with modern architecture (e.g., "barn-style" houses). Due to their high rigidity, they are excellent for large glazing, including knee windows.
In the OKPOL offer, you will find valued and technologically advanced models of PVC windows, perfectly suited to Polish conditions, including the series: KPVCN N22, KPVCU N22, KPVCP N22 and KPVCL N22.
Second – Technical Parameters and Polish Standards
Choosing the material is just the beginning. Equally important (and in the face of rising energy prices – the most important) are the technical parameters of the joinery.
The absolutely key indicator is the heat transfer coefficient for the entire window (Uw). The lower its value, the better thermal insulation properties the window has. In winter, it retains valuable heat inside, and in summer, it prevents the attic from overheating. According to the current Technical Conditions in Poland (WT 2021), the maximum allowable value of Uw for roof windows is 1.1 W/(m²K). By choosing energy-efficient models, you realistically reduce your heating bills.
Acoustic insulation is also significant, defined by the Rw (dB) coefficient. The higher it is, the more effectively the window dampens noise from outside. Standard windows exhibit Rw levels of 30-32 dB, which is sufficient for quiet suburbs. For homes located near busy streets, models with enhanced insulation (around 40 dB) are recommended.
Third – Comfort of Use in the Attic
The type of fittings used and the axis of rotation will determine daily convenience. Among roof windows, we most often distinguish:
Rotating Windows: A classic and the most popular solution. The axis of rotation is located halfway up the sash, making it easier to clean the outer pane from the room level.
Tilt and turn windows: The pivot axis is placed higher, so when opened, the sash does not enter the usable space of the attic – ideal for tall people.
Tilt and turn windows: Combine both functions, providing maximum freedom.
In modern construction, the aforementioned knee windows (reaching almost to the floor) and safe roof hatches facilitating chimney work are increasingly used. It is also worth paying attention to accessories – air inlets (micro-ventilation) that prevent mold formation, or easily washable coatings on the glass.
Fourth – types of security (including anti-burglary)
The feeling of safety in your own home is essential. High-quality roof windows are factory-equipped with safe glazing packages (e.g., with an external tempered glass, resistant to hail).
In the context of burglary protection, the key element is anti-burglary film (laminated glass from the inside), which, in the event of a strike, does not shatter into sharp pieces but cracks, keeping the glass in the frame. Additionally, reputable manufacturers use special reinforced bolts, key-operated handles, or locking buttons that prevent the window from being opened from the outside.
Fifth – operating costs and lifespan
Investing in roof windows does not end with their purchase and installation. It is worth considering the costs and time spent on their subsequent operation. High-quality PVC profiles (like those used in OKPOL models) are virtually maintenance-free – they do not require painting, and are resistant to mold and corrosion. On the other hand, if you choose wooden windows, you must account for the need for regular cleaning with special preparations, and approximately every 5 years – for a comprehensive and time-consuming renovation of the paint coatings. Therefore, the choice of the right material should be dictated not only by taste but also by the lifestyle of the household members.