Types of Windows on the Market – How to Choose the Ideal Roof and Facade Windows?
Choosing the right joinery is one of the most important decisions when building or renovating a house. Properly selected windows not only illuminate interiors but primarily safeguard the household budget by minimizing heat loss. The modern market offers a vast selection of solutions that must meet stringent legal requirements.
According to the current standards WT 2021, the maximum heat transfer coefficient (Uw) for facade windows cannot exceed 0.9 W/(m²K), and for roof windows 1.1 W/(m²K). What types of windows can help meet these standards? Below we present a comprehensive classification.
Classification of Windows by Material
PVC Windows (Plastic) – made from high-impact polyvinyl chloride. Their profiles are divided by internal chambers, which provide excellent thermal insulation. Depending on the thickness of the outer walls of the profile, these windows come in three classes: A (highest), B, and C. They have gained immense popularity due to their excellent thermal parameters, attractive price, moisture resistance, and easy maintenance. They are the most commonly chosen windows in energy-efficient construction.
Wooden Windows – produced from high-quality softwood (e.g., pine) and exotic wood. They are protected with eco-friendly varnish stains, giving them resistance to external factors. Valued for their natural, noble appearance, which gains character over time. Wood features excellent insulation properties but requires regular maintenance (cleaning and renewing the paint coatings).
Aluminum Windows – increasingly chosen in modern construction, especially for projects with large glazing. The rigidity of aluminum allows for the creation of slim and very durable profiles. Modern systems with thermal breaks enable them to achieve insulation parameters compliant with WT 2021 standards, and an additional advantage is the lack of maintenance requirements.
Types of Windows by Location in the Building
The key criterion for classification is the installation location, which defines the window's construction:
Facade Windows – the basic type of joinery installed in the vertical walls of the building.
Roof Windows – installed directly in the roof slope. They provide up to 50% more natural light than vertical windows of the same area.
Knee Windows – combine the advantages of vertical and roof windows, illuminating the floor in the attic.
Roof Hatches – serve a dual function: they illuminate the attic and provide safe access to the roof (e.g., for a chimney sweep).
Balcony and Terrace Windows – large-scale glazing that also serves as exit doors.
Window Automation and Smart Home Accessories
A modern attic is an intelligent attic. To facilitate the daily operation of roof windows (especially those installed high, out of reach), automatic control systems are increasingly used. By utilizing dedicated accessories, such as control modules ISC I22 and advanced weather sensors (e.g., models IGCV I22), we gain the ability to remotely open windows and integrate them with a smart home system. These modules can automatically close the window in case of detected rainfall, ensuring the safety of the interior.
Types of Windows by Opening Method
The method of opening should be adapted to the ergonomics of the interior and guarantee comfortable ventilation in accordance with the standard PN-83/B-03430.
Facade Windows:
Swinging – open inward across their entire width.
Tilt-and-Swing – the most versatile; they can be fully opened or tilted from the top for ventilation.
Tilt – open from the bottom outward, allowing for ventilation even on rainy days.
Sliding (HS / PSK) – mainly used in terrace joinery; the wings slide parallel to each other, saving space in the living room.
Roof Windows:
Rotating – a classic solution with a pivot axis in the middle of the frame. The rotation of the wing facilitates safe cleaning of the outer glass.
Tilt – the pivot axis is located at the upper edge, so the open wing does not take up space inside the room.
Rotating-high-axis – the pivot axis is raised to about 2/3 of the window height, making it easier for tall people to approach the edge of the window freely.
Rotating-tilt – premium class models with two independent pivot axes (at the top for free viewing and in the middle of the frame for cleaning).
Construction and Number of Panes vs. Energy Standards
The construction of the window directly translates into its thermal and acoustic parameters. The most commonly found are single-frame windows (composed of one frame and one wing). More complex constructions, such as cross windows, box windows, or frame windows, are now almost exclusively used during the renovation of historic buildings.
As for glazing packages, the WT 2021 standards have pushed windows with weaker parameters out of the market:
Double-glazed windows – consist of two panes of glass separated by a space filled with noble gas. They are suitable for utility buildings or modernized facilities where thermal requirements are somewhat more lenient.
Triple-glazed windows – the current standard in modern single-family home construction. Two chambers filled with argon or krypton drastically reduce heat escape, ensuring compliance with WT 2021 requirements and providing high energy efficiency.