Monthly Archives: April 2017

What should you look for in an energy efficient bi-folding door?

red brick house

Bi-folding doors have become increasingly popular in recent years, and it’s no surprise.

Not only do they lighten up a room significantly, but they create a rather enviable inside/outside space. By folding the doors fully back, you have an uninterrupted view out into your garden, essentially bringing your garden into your room and vice versa.  But as bi-folding doors take over an entire wall space, on top of the aesthetic appeal, you should also ensure that your doors are energy efficient, helping keep your home as warm and comfortable as possible, whilst keeping your bills low.

So, what you should look for in an energy efficient bi-folding door?

Quick Slide Ltd very kindly provided their thoughts on this subject as follows.


U-values measure how effective a material is as an insulator. The lower the U-value, the more efficient the material. The more efficient the material, the lower your energy bill will be. With bi-folding doors you generally want a value of 1.4 or lower to ensure that you have optimal thermal performance. There are a variety of energy efficient bi-folding doors, with low U-values. For example, WarmCore doors have been developed to achieve a U-value of 1.4W/m2K with double glazing, and a U-value of 1.0W/m2K with triple glazing.

Weather Testing

A suitable weather resistant bi-folding door should have undertaken a weathertightness test, more formally known as a BS6375 Part 1. This tests the air permeability (varying levels of air pressure are applied to the material, testing the amount of air leakage), watertightness (water is sprayed at varying pressures to see at what point it starts to penetrate) and wind resistance (varying levels of wind pressure are applied to see what the maximum resistance levels are). Purchasing a bi-folding door that has undertaken a weathertightness test, ensures you the peace of mind that your doors will keep your home fully insulated from all weather conditions.

Polymide Thermal Barrier

Aluminium bi-folding doors that have been upgraded to polymide thermal barrier technology over old resin thermal barrier give at least a 30% improvement to thermal efficiency. The advanced profile technology creates a thermal transmittance barrier between the cold outside and the warm inside.

CE Marking

All UK manufactured bi-folding doors should be CE marked. In order for a product to receive this accreditation, the manufacturer must present evidence under a series of categories, this includes thermal and weathertightness. Therefore, you can rest assure that any door you are purchasing with this marking, will be within the UK standard for both thermal and weathertightness.

Quick Slide Ltd have not paid for this article, nor have we paid them. The views expressed are their own. Other companies wishing to publish informative articles should submit them to the editor. 

Read more about their Bi folding doors here, their website claim they are

A well-established business specialising in the manufacture of sliding sash windows, casement windows and doors, bi-folding- and sliding patio doors in PVC-u, Aluminium and Timber. We work with professionals to ensure we provide our trade partners with the highest quality of windows and doors throughout the UK at all times.

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