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Rooflights: What Are U Values and Why Are They Important?

Increasingly, new build projects as well as existing buildings are maximising the use of natural light together with the thermal properties of modern glass, to create a revolution in how we look at heat retention and accessing light sources.

When you consider the costs involved in paying for artificial light and heat, especially at a time when energy prices are soaring so significantly, rethinking our approach to and reliance on these basic needs makes a lot of sense.

A U value tells us how much heat is lost from a building through different elements, such as windows, walls and floors.

It is a measurement of heat transference, also known as the “overall heat transfer co-efficient”, meaning the higher the number value, the more heat is being lost, and the less environmentally friendly the building is. A lower value therefore indicates greater insulating properties and is more energy efficient.

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If you would like further information about EOS, our products and how we can help, why not request a brochure.?

Calculating the U Value

The U value of a building element is calculated by working out heat loss for each component of the building. This is determined by the material used, its thickness, and its positioning.

Current building regulations in England and Wales allow for all non-domestic applications, the worst acceptable standard for the thermal performance (U-value) of rooflights in new build work is stated as 2.2 W/m2k. For refurbishment or domestic applications, this figure is reduced to 1.8 W/m2k.

Rooflights are made up of a number of different component materials that each have different properties when it comes to heat transference. Therefore, to find out the U value of this type of element, a number of factors need to be determined.

It is simply not enough to state the glass centre pane U value of the glass unit as this does not represent the U value of the entire rooflight product.

Equally, thermal comparisons between competing rooflight products can only be made when U values for the whole rooflight are considered. A poorly designed triple glazed rooflight product may in fact perform worse than a well-designed double glazed product albeit the centre pane U value of the triple glazed glass unit may be better than that of the double glazed glass unit.

Energy Effecient Rooflights.

Energy efficiency is at the core of our product range at EOS, each of our rooflights boasts U Values significantly lower than current and future building regulations. Our standard fixed products boast a 0.97 W/m2K U Value whereas our ECO Range is tested to a market leading 0.65Wmk system U Value.

In fact our U values are so low that official building standards permit you to increase the amount of glass within your roof area.

So, as well as flooding a building with daylight to naturally enhance the indoor environment, EOS rooflights ensure green energy efficiency by reducing the need for CO2-emitting artificial lighting, whilst guaranteeing that heat isn’t lost unnecessarily.

For green efficient skylights with low U Values, speak to the EOS Rooflights team today

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4.86 Average

201 Reviews

Anonymous

Friendly, helpful and informative customer service. Good product and quick delivery.

Posted 5 months ago

Kairen

Beautifully designed, high spec, and look fantastic. Simple website and helpful service from guys at EOS. Prompt delivery. This is a quality product.

Posted 5 months ago

Lee

Morning big thanks to Chris and his team, very helpful their product is by far the best complete roof light system out there. I highly recommend this company will be using them again, ps also very easy to install Kind regards Lee

Posted 5 months ago

Sarah

They were extremely efficient and most of all knowledgable about their products - they offered detailed information and were extremely patient with all my questions. They managed to ship the product very quickly and it arrived to us the same week. Very happy with EOS. The product itself is great!

Posted 5 months ago

Clifford Nicholson

Very efficient and easy to deal with.

Posted 5 months ago

Tim Lancaster

The roof light that I ordered arrived on time and appears to be very well made. The instructions were clear and my builder had no problems installing it, other than in getting it onto the roof as it is very heavy. The roof light looks good and I am glad that I was able to buy one with such a good U value as I wanted the light without the loss of heat.

Posted 5 months ago

Mark Harris

Great service, nothing is a hassle and super helpful

Posted 5 months ago

Carl Smith

Prompt delivery, excellent quality and easy to install, a great product.

Posted 5 months ago

Anonymous

EoS and their staff were very helpful in design and specification for a large skylight. They gave top quality support in the runnup to installation and were very accommodating in helping to source correct vehicle to crane in said (very heavy) skylight.

Posted 5 months ago

Kay

I'm delighted with my EOS roof lights. I had to choose roof lights that were slightly smaller than I wanted, due to design constraints, but the amount of light provided is wonderful and unexpected. The whole kitchen is lit up, even when the curtains are closed across our french doors. Many thanks EOS, A happy customers.

Posted 5 months ago

Timothy Rickford

Very happy with the service from EOS staff and quality of the product. Would definitely use again.

Posted 5 months ago

Anonymous

Great after sales support and service from knowledgeable staff. Also a really good quality product.

Posted 5 months ago

Anonymous

Excellent service! The windows are gorgeous and their staff are always so available and happy to answer questions on short notice, and I had a lot!

Posted 5 months ago

Sarah Willett

Really helpful on specifying size and advice on installing.

Posted 5 months ago

Anonymous

Really nice company - fast, efficient and pleasant in all my dealings with them. There was a delivery error and they worked hard to find a solution as quickly as possible and did everything they said they would. Really impressed all round - when you are having an extension on your house, you end up dealing with lots of suppliers. I wish they were all as good as EOS.

Posted 5 months ago

Rebecca Phillips

Eos gave us a really good service, good communication throughout, most importantly the roof lights are amazing - really good quality and look great

Posted 6 months ago

Luke Carroll

Ease of installation and provided a huge amount of light to our extension. We chose the electric opening option which is fantastic for ventilation.

Posted 6 months ago

Rebecca Phillips

Very good service but most importantly excellent quality roof lights, very pleased thank you

Posted 6 months ago

Anonymous

They delivered what I wanted!

Posted 6 months ago

Anonymous

Good service and communication, competitive prices. Very helpful and understanding.

Posted 6 months ago

Colin Nelson

Great product, helpful customer service staff who answered any question I had.

Posted 6 months ago