Quality glazing has a significant and noticeable effect on energy efficiency, keeping your home warmer and your bills lower. But what exactly makes double glazing energy efficient? On this page, Future Windows Ltd explains the three main factors which contribute to the performance of our products. Having been manufacturing and installing windows, doors and conservatories for more than 30 years, we ensure expert quality and performance, whatever your requirements. Among other things, our skillset covers uPVC windows, aluminium windows, aluminium doors, bi-fold doors, patio doors, French doors, composite front doors and various conservatory styles.
Covering Burgess Hill and all surrounding areas from our base in Horley, we provide complete services for customers in the South East. We work on homes of every size, age and design, and are sure to have the perfect solutions for your property.
Introduced in 2004, the Window Energy Rating (WER) system provides grades from A to G, with A being the best. Since 2010, replacement windows must have a minimum WER rating of band C to comply with building regulations. A Door Energy Rating (DER) system was introduced in 2011 to grade bi-fold doors, composite front doors and all other door types.
WER and DER ratings consider the following:
U-value measures how easily heat can pass through a material. The lower the U-value, the greater the insulation provided by the material in your Burgess Hill property. For example, modern double glazing can achieve a U-value as low as 1.4W/m²K (heat loss in watts per square metre of material), while triple glazing can reach 0.6W/m²K.
At Future Windows, we make sure the glazing in all our products has an excellent U-value for optimal thermal performance alongside low U-values for other materials. This applies to our:
G-value is a scale from 0-1. It measures how much heat from the sun can pass through a material, with a higher number indicating high solar gain. Double glazing can maximise heat from the sun to help heat your Burgess Hill home. This is beneficial in cooler climates, such as the UK, where it acts as a passive form of heating.
To avoid overheating in rooms which get a lot of direct sun, such as some conservatories, you may wish to consider triple glazing, which offers lower solar gain. Furthermore, to prevent issues with overheating, Part L of the building regulations restricts the amount of glazing that can be used in buildings.
Solar gain is not included in the rating process for external pedestrian doors. However, ratings for doors with a glazed area of 60% or more, such as glass bi-fold doors, do include G-value.
L-value measures how airtight windows and doors are. Products with lower values are more draught-proof. Modern products are generally fully airtight and should have an L-value of zero. It is important to note that air leakage is defined as the uncontrolled flow of air. This is different to ventilation, which is controlled airflow.
When you choose Future Windows Ltd for your project in Burgess Hill or the surrounding areas, you have assurance of fully sealed and airtight uPVC windows, aluminium windows and external doors, including aluminium doors, composite front doors, French doors and patio doors.