Roof Windows

A roof window is an opening system that's integrated into the structure of a building. It's also often referred to as a Velux, after the name of the world's leading roof window company. Chosen for their look or if standard windows can't be fitted, roof windows let a lot of light into the interior and generate energy savings.

Why install a roof window?

There are many reasons why you might want to install roof windows: the look, structural constraints, energy or acoustic performances, etc.
  • A feeling of space and an obstacle-free panoramic view
Roof windows are pleasant to look at, make a room seem larger and make an interior space look much more modern. If they're large or act as an extension of a window on the front of a building, they provide a greater view of the surroundings.
  • More interior light
Roof windows create an additional light source that lets up to 40% more light into a room, making them a perfect solution for creating an aperture in a dark room. Creating an overhead aperture also lets in daylight for longer, regardless of which direction the window is facing.
  • Light and well-ventilated lofts
Installing a roof window is a perfect solution for refurbishing lofts or attic rooms in which standard windows can't be fitted. Roof windows are designed to adapt to the pitch of a roof, whether it's 15° or 90°. There also solutions to prevent overheating in lofts during the summer: thicker glazing significantly enhances thermal efficiency and can also be tinted to filter the sun's rays. Roof windows also allow a loft to be vented easily, thereby preventing heat from building up.
  • Energy savings
Replacing old windows with more insulating models usually cuts heat loss in a room by 13%. Roof windows are very energy-efficient and provide optimal thermal insulation, thereby creating significant energy savings. This thermal saving quickly offsets the price of the initial outlay on roof windows.
  • Effective sound insulation
High-quality glazing in roof windows also provides good sound insulation. This is ideal for shielding you from surrounding disturbances such as traffic noise. If you fit roof windows in a bedroom, the effective sound installation ensures a good night's sleep.
  • Optimal ventilation
A Velux window allows you to ventilate obstructed rooms or create an air flow in rooms that already have another window. This refreshes the air more effectively and ensures better temperature control in a room. Roof windows are also an excellent solution for a room such as the bathroom, which has high humidity but not enough ventilation to maintain healthy air.

The different types of roof windows

A wide range of roof windows are available on the market. Each type has its benefits, whether in terms of thermal and sound insulation, quality or comfort.
  • Wood, PVC, aluminium… which type of material is best for roof windows?
There are all types of products: roof windows made from wood, aluminium or PVC are the most common, although there are also windows with a zinc or polyurethane-coated wood frame. Although wood looks very good, it's expensive and this type of material requires regular maintenance. PVC is less attractive but easier to maintain day to day and is more affordable. PVC roof windows also provide good thermal and sound insulation.

Another alternative is aluminium windows, which are more attractive than the PVC version while also offering comparable insulation. Aluminium is hard-wearing, doesn't rust and is easy to maintain. Its price is a good middle ground between the cost of wood roof windows and PVC windows.
  • The opening mechanism
There are three main categories of roof windows based on the opening mechanism.
- Projection opening: the bottom of the window is pushed towards the exterior. This is the ideal solution for roofs with a gentle pitch (up to 55°). The projection system also has the advantage of not taking up space in the room.
- Rotation opening: the top of the window is pulled downwards on a swivelling central axis. Rotation is a simple solution that's suited to all types of pitches, although it slightly intrudes into the room.
- Lateral opening: the roof window is opened to the side (like a standard window, except that it opens outwards rather than inwards). This can be useful if you want to allow access to the roof.
  • Manual or motorised opening mechanism?
Roof windows can have a manual opening mechanism (the frame is moved directly by hand) or a remotely motorised mechanism to control the opening of windows that are out of reach or to open all windows using a remote control. The motorised mechanism can be electric (the roof windows are fitted with a motor) or solar-powered.
  • The type of glazing
When choosing your roof window, you'll need to select the type of glazing you want. Obviously, single glazing costs less than double or triple glazing. Nevertheless, it may be worth spending more, as the window's thermal and sound insulation depends on the quality of the glazing. The cost will be quickly offset by the energy savings made and the greater comfort that good-quality glazing provides. Good glazing limits heat loss during the winter, prevents overheating in warm weather and filters sound from the outside for maximum comfort in your home. Check the thermal rating of the windows before making a choice, as well as the soundproofing rating.
  • Roof window options
Many accessories are available for roof windows, which you should select based on the window's position in your home and the frame's position relative to the sun. There are blackout blinds for shading your home regardless of how sunny it is, mosquito nets that allow you to keep your roof windows open without letting insects inside and a whole range of different styles of blinds for all tastes: curtain blinds, Venetian blinds with slats, Roman blinds, pleated blinds, sunscreen blinds, patterned blinds, etc. There are also outdoor roller blinds that block out the light during the day and maintain thermal comfort in your home. They can be electric or run on solar power. Discover all our products

Roof windows and security

Like all openings to the exterior, a roof window provides a potential entry point for burglars. This means it's important to have a high-quality installation that guarantees security and reduces the likelihood of an intrusion taking place via the roof. Most roof windows include a locking bolt, with or without a key, to prevent rotating windows and projection windows being opened from the outside.

Some models are even reinforced and allegedly impenetrable, including reinforced hinges and burglar-proof glazing that even stops bullets. Laminated safety glass provides better resistance to impacts, and a roof window provides additional security. An alarm system can also be installed in roof windows.

Legislation UNI ENV 1627 categorises roof windows into six classes, ranging from 1 (windows that can be opened using simple small tools) to 6 (roof windows that can withstand blows from an axe, grinder, hammer drill, etc.).

A few rules to follow when installing roof windows

Before installing roof windows in your home you'll need to submit a declaration to your local town hall. Although you don't need a building permit for roof windows, you must follow certain rules, notably those stated in the local urban planning regulations ("PLU"). The town hall may also ask you to comply with specific dimensions for your roof windows or install protective bars or guardrails.

You must also respect your neighbours' privacy and comply with the distances stated in the urban planning regulations concerning adjoining properties. Lastly, if you're installing roof windows in a multi-occupancy building you must obtain the co-owners' approval before beginning the installation, particularly if it changes the look of the building.

Roof windows can have standard dimensions or be made to measure. According to the thermal regulation RT 2012, the glazed surfaces must amount to around 17% (one sixth) of the habitable surface area in a new building. This can be a single roof window or several small windows, which can be square or rectangular, etc.

The position of the windows also needs to be carefully considered: if opened manually, the window needs to be a maximum of 2.20m from the floor so it can be accessed. The height also depends on the pitch of the roof: the less this is, the higher the window needs to be.

Lastly, to ensure perfect sealing and optimal isolation it's best for the installation to be carried out by professionals, particularly because working on a roof can be hazardous for homeowners who want to do the job themselves but are inexperienced and don't have the proper equipment.

Smart roof windows for optimal comfort and management

Smart roof windows, the latest innovation, have added another dimension to the home. Using sensors, smart commands and a Wi-Fi connection it's easy to optimise the opening and closing of roof windows. For example, the app developed by Velux in partnership with Netatmo lets you control your Velux Windows remotely, as well as intuitively.

The automatic adjustment controls the opening of your roof windows according to the indoor environment measured by the sensors (temperature, humidity, air quality). This allows you to maintain optimal comfort, healthy air and an ideal temperature in all circumstances. The remote management feature enables you to check the position of the Velux windows at any time, while the proactive smart system controls the opening of the roof windows according to the weather.

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