More glass is not automatically the whole answer.

As building performance becomes increasingly important, triple glazing is often seen as the obvious upgrade from double glazing.

But when selecting roof glazing, the best solution depends on more than simply counting panes of glass.

A high-performance roof window is a combination of the glazing, frame, thermal breaks, spacer system and the way all those elements work together.

Triple glazing can provide a significant improvement in thermal performance and can be particularly valuable where reducing heat loss is a priority. However, a well-designed thermally broken frame with correctly specified double glazing may also provide an appropriate solution for many projects.

There are other factors to consider too.

Solar heat gain can be beneficial in some situations and undesirable in others. A roof window can receive considerably more direct solar exposure than a vertical window, so the Solar Heat Gain Coefficient, or SHGC, can be just as important as insulation performance.

Visible Light Transmittance also affects how much daylight enters the building. Selecting increasingly high-performance glass without considering the wider project requirements can sometimes reduce one of the main reasons the skylight was installed in the first place: natural light.

Size, pitch and whether the roof window is fixed or opening can also influence the glazing options available.

The key is to treat glazing as part of the overall roof window specification rather than selecting it in isolation.

Harmony Roof Windows are available with a range of double and triple Low-E glazing configurations, allowing the specification to be tailored to the climate, building design and performance objectives of the project.