U-Values

Definition

A U-Value is a measure of air-to-air heat transmission (loss or gain) due to thermal conductance and the difference in indoor and outdoor temperatures. As the U-Value decreases, so does the amount of heat transferred through the material. The lower the U-Value, the better.

To satisfy clients needs for greater sustainability and thermal efficiency, a u-value calculator has been made available, providing specific thermal performance relating to the Jedson range of composite door styles and sizes.

Breakdown of Calculation

The composite door u-value calculator opposite is based on known u-values given by the individual part manufacturers. The tables below show the u-values of the relevant parts of the door, and the area of the glass for each style. The area of the glass is fixed regardless of overall door size.

Component U-Value
Door Outer
Solid door blade
Standard Double glazed unit
Double glazed unit with Warm Edge spacerbar
Double glazed unit with Warm Edge, Softcoat and Argon Filled
1.60 w/m²K
0.85 w/m²K
1.80 w/m²K
1.50 w/m²K
1.30 w/m²K
Door Style Area of DGU
Bordesley, Cleve, Margam
Bourn
Cartmel
Boxgrove Two
Boxgrove Four
Glastonbury, Ewenny
Glastonbury Three, Ewenny Three
Pershore
Old Pershore
Balmerino, Old Balmerino
0.37m²
0.51m²
0.48m²
0.06m²
0.30m²
0.11m²
0.35m²
0.05m²
0.08m²
0.22m²