What exactly are U Values and how are they calculated?

What does ‘U’ Value mean and how is it Calculated?

In the Winter months, many of our clients talk to us about the thermal insulation properties of our windows, doors and roofs. Obviously, the less insulating a product, the more energy that is lost, resulting in higher energy bills. It is therefore important for higher quality, more efficient aluminium products to be distinguished from lower performing products when customers are choosing their new doors and windows.
So, how is thermal performance calculated? Well, the most commonly used measurement in the construction industry is U value. U values are a measurement of heat transfer throughout a material, divided by the difference in temperature across the structure. The resulting units are W/m2K – the lower the u value, the better insulated the structure is.

Points to consider

Whilst the product itself can have an exceptionally low u value, the standard of the fitting plays a massive part of the overall performance of the window/door – poor quality bridging materials, air gaps and even the mortar can considerably affect the insulation properties. NOW Aluminium offer a supply only service but your builder/fitter can follow our simple set-by-step instructions to install our high performing products to the highest standards.

Understanding ‘real world’ u values

Whilst many competitors market their products with ‘headline’ u values, the actual performance of each of their products is likely to fall short. At NOW, we would suggest being wary of such figures as in reality, each bespoke bifold door will have a different u value performance to another. For information purposes, our glazed NW1 aluminium bifolding door system has a standard u value of 1.4.

If you have any questions regarding thermal insulation, feel free to get in touch with one of our sales advisors who will be happy to help.