Both bring daylight from above, but they perform different jobs

One of the first decisions when specifying a roof window is whether it needs to open.

For many projects, a fixed roof window is exactly what is required. Its purpose is simply to bring natural light into a part of the building where conventional windows cannot achieve the same result.

Fixed roof windows can also offer greater flexibility where particularly large glazing sizes or higher thermal-performance glazing configurations are required.

Opening roof windows add another benefit: ventilation.

They can be particularly useful where warm air naturally accumulates at high level, allowing air to be released through the roof and helping create natural air movement through the building.

Motorised operation makes opening roof windows practical even where they are well above normal reach, and they can potentially be integrated with wider building control systems depending on the project requirements.

But an opening unit is not automatically better.

If ventilation is already being adequately provided elsewhere, adding an opening mechanism may introduce functionality that the project does not actually need.

Other considerations include the required opening area, roof pitch, window size, glazing specification, controls and how the opening roof window fits within the building’s ventilation strategy.

Harmony is available in both fixed and opening configurations, allowing different roof windows within the same project to perform different roles while retaining a consistent architectural appearance.

The best starting point is simple: decide what you actually need the roof window to do, then specify around that requirement.