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Heat loss through skylights – is this an issue?

28 April 2016
There is a common fear among many homeowners that heat loss through skylights in the colder months is a key factor that makes homeowners avoid installation.

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Allegedly, a skylight in the roof of a house will tend to lose between 35 and 45 per cent more heat in the winter; but these figures are most relevant to non-thermally broken skylights.

As the warm air in a house soars towards the ceiling of your home it comes into contact with the cold surface of the skylight. As the air cools it forms a significant draft loop that can greatly harm the temperature levels below; known as convection heat loss.

In dual-paned skylights that aren’t thermally broken, the warm air still rises upwards until it meets the cold upper surface. The warm air then falls to be replaced by more warm air from below. In the event that the two glass panels have more than a quarter of an inch of space between them, it can circulate air more intensely, creating an even bigger problem.

Radiation is another big issue for non-thermally broken rooflights. The supporting frame that fits between the roof structure – known as an integral upstand – simply increases the surface area and therefore the potential for further heat loss.

Fortunately, at Sunsquare we are world leaders in the design, manufacture and installation of flat roof skylights, boasting the only weather facing product range to hold the BSI Kitemark for weather testiness, wind loading and air permeability.

We’re therefore able to provide a solution to skylight heat loss through dual-pane skylights and through the rooflight’s supporting frame.

Thermally broken flat rooflights

Every Sunsquare skylight that leaves our manufacturing facility is thermally broken, helping your homes to stay warmer and drier whilst enjoying the abundance of natural light that floods into your interiors below.

The extruded aluminium profile that our rooflights are made from transmits heat and cold very efficiently. As we’ve already discussed above, if the external temperature can control the skylight frame it opens up both heat loss and condensation issues for your home.

Our roof windows are thermally broken using multiple polyamide insulating sections and are factory-glazed with a 24mm argon-filled and soft coat low-E insulating glass unit.


At Sunsquare, our upstands don’t just sit there to help your skylight look architecturally stunning, they give you and your property tremendous energy benefits too.

Although a Sunsquare upstand is an optional purchase, we find that many of our clients take advantage of them as we are able to accurately calculate the U-value of every upstand that leaves our factory.

Each upstand is fully insulated with a U-value of 0.58 and zero per cent chance of condensation. The insulating foam that forms the core of the Upstand is a highly sophisticated chemical compound foam, tested to take into account all possible weather scenarios on flat roofs.

It’s not only energy efficient, it makes sure your skylight fits and fits properly. The upstand is external to the rooflight itself, unlike many other companies that sell their rooflights with integrated upstands.

The issue with integrated upstands is that in the event of a problem with the skylight or roof membrane, the roof structure itself will often need to be compromised to fix the problem.

With Sunsquare’s improved BSI Kitemarked designs it’s never been easier to overcome the drawbacks of heat loss through skylights, allowing you to make the most of the natural light without having to compromise on colder, less comfortable living environments.

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