What will June’s changes to Building Regulations mean for glazing specification?

By Sonia Travis, Commercial Sales Manager for the North of England, NorDan UK

In a shift towards The Future Buildings Standard, from today (15 June 2022), changes to Part L (conservation of fuel and power) and Part F (ventilation) of Building Regulations come into force, so that all new homes and buildings in England are futureproofed with low-carbon heating systems and high levels of energy efficiency.

These changes should mean that from today new homes will deliver CO2 savings of 31%, and new non-domestic buildings will deliver CO2 savings of 27%.

This is an interim uplift ahead of the full technical specification for The Future Homes Standard that will be consulted on in 2023, with legislation and implementation by 2025, with the ultimate aim of reducing total building carbon emissions by 75% to 80% by 2030 in order to meet climate targets.

Those who specify glazing products take note; these changes are having a significant impact on window specification, as they affect the maximum allowable u-values of glazing products.

U-values are a measure of heat loss through a material, and they’re used to measure how effective elements of a building's fabric are as insulators; that is, how effective they are at preventing heat from transmitting from the inside to the outside of a building. With u-values, the lower the figure the better.

The current maximum allowable figure for windows stands at 1.6W/m2K, but from June this will be reduced to 1.2W/m2K, and it is likely that this figure will drop to 0.8W/m2K in 2025.

What does this mean for window specification?

Heat is not only lost through window glazing itself, but also through the frame, and certain materials are better at preventing heat transfer, so lend themselves to lower u-values.

In general, PVCu, aluminium and composite windows can only achieve a u-value of 1.2 by being triple glazed. However, this is not the case for NorDan’s high-quality timber framed windows, as they are able to achieve a u-value of 1.2 with double glazing, and a u-value as low as 0.74 with triple glazing.

Many manufacturers will have to switch to triple glazing to achieve 1.2 with a resultant increase in costs and embodied carbon too. There are many windows manufacturers that are having to undertake a complete system redesign to meet the anticipated changes in 2025.

At NorDan we’ve met the standards set by Part L for many decades, because our windows are designed and tested to exceed British Standards for weather performance, due to our products being originally designed for harsh Norwegian maritime winters.

Whether it is thermal bridging, air permeability or thermal transmittance, our typical double-glazed windows are best-in-class, meaning that we can achieve new Part L. We can also meet 2025’s predicted change to standards with ease today.

Understanding the impact of changes to building regs can be daunting for housing developers and specifiers, however our specification team is here to help. So please get in touch with us as early as you can in your project for a no obligation chat, our team is ready and willing to help you navigate these adjustments.

I’m Sonia Travis, Commercial Sales Manager for the North of England at NorDan UK Ltd, with over 30 years’ experience of fenestration of all types and materials. If you’d value further input or discussion on any of the issues raised in this Blog please email me at:

Jun 15, 2022
Go back

Explore NorDan · A leading window and door manufacturer