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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

261 Reviews

MarkLaws

We are very pleased with our EOS Rooflights Our Builder was also very impressed with the quality and will use them in future

Posted 1 week ago

AlexanderWhite

Im very happy indeed. Instructions were clear, it went on a treat and looks great. It was a pleasure dealing with you, I shall recommend you

Posted 2 weeks ago

Anonymous

Very helpful customer service

Posted 3 weeks ago

JustinGourley

Most importantly of all, a great product - smart and clean design - looks superb. Service was excellent, very responsive - addressing questions quickly and adapting the design as needed. Fully recommend

Posted 1 month ago

Anonymous

We have had very good service from you delivery on time and fitting very easy.We are now enjoying the benefits of having the room flooded with light.Many thanks

Posted 1 month ago

KateAllen

EOS where very helpful throughout, the pricing was competitive with all the quotes we received and the walk-on rooflight was exceptionally well made. We prepared the opening using EOS details and plans and it came exactly as described and fitted perfectly (this seems obvious but surprisingly doesn't always happen). I would 100% use them again and would recommend EOS to others without hesitation. I am extremely pleased with the finished rooflight and it looks brilliant installed. My contractor said it was perfect and came exactly as described too, so good all round. No pictures at present but can provide later! It looks fab!

Posted 2 months ago

Anonymous

EOS supported with

Posted 3 months ago

AshleyNicholson

perfect , elegant and simple which is what we wanted. looks good. Builders told me easy to fit and fiiting instructions were appreciated as they were very clear

Posted 3 months ago

AsifAhmed

Excellent service, I had a few questions regarding installation and these were answered very quickly, very happy to recommend EOS!

Posted 4 months ago

NicoVatnikaj

Very happy with the service on time no delays

Posted 4 months ago

Anonym

Quick delivery and great product

Posted 4 months ago

SeanOwen

Looks great. Very solid, good quality. Service was wonderful, delivered in a couple of days as promised

Posted 6 months ago

Andy

We purchased a flat roof light last year and we're so glad we did. It's made such a difference to the light we get into the room and looks amazing too. Top product and great results. Our builder was impressed with it too and how quickly his question was answered when he was installing it.

Posted 6 months ago

Anonymous

As part of my build project I researched many companies looking for good quality skylights and a company that could offer both opening and fixed skylights. EOS fitted all my requirements. Both Elliot and Chris were consummate professionals in dealing with my queries and ensuring I got my delivery on time. The skylights were solidly constructed and we love them. The only thing I will say is that if you order a bespoke size, make sure you can wait 6 weeks from order to delivery.

Posted 7 months ago

IanGriffiths

Very pleased with rooflights . Easy to fit . Great communication both when ordering and delivering. Would definitely buy again.

Posted 7 months ago

PeterJaggard

Brilliant company to work with, always ready to assist, and very good communication. Excellent product, of great quality and looks brilliant, well pleased. Thanks to all at EOS

Posted 8 months ago

MadeleineBradbury

Delighted with our rooflights. EOS did everything they said they would do when they said they would do it. We were a bit nervous about doing our own fitting but we got precise, practical instruction diagrams and all went very smoothly

Posted 8 months ago

JeffereySmith

Excellent rooflights and easy to fit

Posted 8 months ago

AndrewHamilton

Excellent product, delivered on time. Would certainly use this company again,

Posted 9 months ago

Anonymous

Rooflights are high quality and fixing instructions clear.

Posted 9 months ago

PaulSeabright

A great product. The speed and efficiency of the online purchase and then the delivery of the items made the process a hassle free pleasure that is all to rare these days.

Posted 9 months ago