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The U-Value Lowdown

Trying to decipher technical terms can be a bit daunting when starting your renovation journey. We’ve put together this article so you can get to grips on U-values and why they are an important factor into choosing the right windows and doors for your home.

What exactly is a U-Value?

U-values are used to measure the effectiveness of preventing heat loss from inside a building. The lower the u-value of a window or door means the slower the heat is able to transmit through it and so the better it performs as an insulator.

How would you measure that?

U-values are measured in watts per square metre, per degree Kelvin

(W/m²K). For every degree of temperature difference in the air for the inside and outside of the window or door, the U-value is equivalent to how many Watts of heat are lost.

For example – If the U-value is ‘1’ for every degree of temperature difference between the inside and the outside, that will mean that one watt of heat will escape your home.

But how does this benefit me?

As the colder months and darker days start to draw in, the benefit of a good u-value means that less energy will be required to heat your home for longer, creating a comfortable home with low running costs. 

What are the ResidenceCollection U-Values?

All 3 Residence Collection Systems can achieve 1.2 W/(m²K) with double glazing and our lowest is

0.74 W/m²K with triple glazing – The certified Passive House standards state that U-values for windows  should be below 0.8 W/(m²K).

Got any more questions? Head on over to our website where you can download a brochure or read our FAQs . You can also contact us directly on



At Residence Collection, we have a range of colours available and can offer everything from timeless classics like Grained White to modern favourites such as Eclectic Grey. Don’t forget, we also offer a dual finish that allows you to find windows and doors that look as good from the inside as they do outside.