Energy performance

Advancing consumers’
energy use

By introducing a new generation of roof windows, based on energy balance principles and rewarded for raising the bar in terms of energy efficiency, comfort and daylight, we also enable our customers and homeowners to gain significant energy savings.

A window is a building component like no other. Its transparency allows pleasant daylight into the building, attractive views to the outside and free solar heat gain into the building – summer and winter, and even on overcast days.

Energy balance a guiding principle in the future

The window is letting in free solar gain in to buildings, and as such, the energy performance of a window cannot be assessed solely on the basis of its insulation qualities. The calculation of the energy performance should therefore also be based on the concept of energy balance, defined as the difference between solar gain and heat loss throughout the entire year.

“Using energy balance as measurement for windows’ energy performance would take all the qualities of the window into account, and not merely its insulation. Looking at the entire window’s energy balance would open new opportunities for creating more comfortable and sustainable building solutions,” says Ulrich Bang, director of Public Affairs, the VELUX Group.

The energy balance of the window is no fixed value. It depends on a number of factors including geographical location of the building, the orientation of the window (North, South, East, West), the slope and size of the window and the quality of the pane.

Energy balance

A window's energy balance is the difference between the amount of heat from sunlight that the window transfers to your home and the amount of heat that escapes through the window.

New generation of roof windows

The new generation of VELUX roof windows are designed to maximise the heat gain through the window in the heating season and to retain the heat inside the building by using high-class energy panes and patented insulation design. It will contribute positively to the energy balance of your home, even on an overcast day.

“The new generation has been rewarded for raising the bar of window energy efficiency, increased comfort and bringing more daylight into people’s lives and will enable homeowners to harvest both significant energy savings and increased life quality indoors,” says Jørgen Tang-Jensen, CEO, the VELUX Group.

A wide range of blinds and shutters have also been designed to keep out the heat when the weather is warm, limiting the use of energy consuming air conditioning. 

1 m2

of a new VELUX roof windows is likely to be more energy efficient than 1m2 of your old roof construction


roof window will contribute positively to the energy balance of your home

Energy balance

is a calculation based on the solar heat gain (g-value) minus the heat loss (U-value)

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