With windows and doors responsible for around one fifth of a building’s energy loss, the choice of material and specification is more important than ever.

At JELD-WEN we provide a range of energy efficient windows and doors that not only keep the heat in, but also insulate homes against outside noise.

Thermal efficiency in windows and doors

Thermal transmittance values are declared in the form of either a U value or a Window Energy Rating (WER). Both are means of compliance with Building Regulations. WERs are commonly specified for replacement windows, with the rating of the product clearly identifiable. U values are used commonly on new builds with the window and doorset specification driven from SAP calculations by the building designer or architect.

U Values

A windows thermal performance is a windows’ whole U value not just the value of the centre pane U value. U values are determined by reference to EN14351-1 and window type is a single frame and fixed sash.

We offer a range of U values depending on the project type to meet new build and other project and regional requirements.

Energy ratings

Energy ratings offer an alternative method of assessing thermal performance and are currently available across all JELD-WEN window ranges.

Independently certified by BRFC they provide:

  • a simple method for comparing the overall energy performance of windows;
  • measure U value, solar gain and air leakage
  • are classified with A+ being the highest, achieved by us on Stormsure Energy+ range
  • are consumer friendly as are used on other consumer products.