Yale is proud to sponsor Clearview ’ s Industry Issues Guide
New Regulations Challenge the Industry
WHAT INSTALLERS SHOULD EXPECT AS WE APPROACH THE FUTURE HOMES STANDARD
Phil Brown , European regulatory marketing manager at Pilkington United Kingdom Limited , part of the NSG Group , outlines the changes to Part L of the building regulations for dwellings in England , and how meeting U-value requirements will help installers to be one step ahead in meeting future standards .
Part L of the regulations is concerned with the energy performance of building elements such as windows and doors , and the changes will further tighten the rules governing the carbon emissions of dwellings , both new and existing .
Fabric first energy efficiency
Over 25 % of the heat from homes and public buildings escapes through the windows , so , with the rising costs of energy and environmental awareness , more emphasis ( and regulation ) is being placed on the thermal insulation of fabric components .
When it comes to replacing windows and doors , the changes to Part L require installers to choose high performance glass products that meet the target fabric energy efficiency rates . This means , where possible , selecting products that limit ‘ back stop ’ values , or U-values – the rate at which heat transfers through a structure or material , divided by the difference in temperature across that structure of building .
Lower ( better ) U-values will contribute towards the overall target performance of the building and help meet the new requirements . For windows in new dwellings , the previous maximum U-value of 2.0 W /( m 2 · K ), has been tightened to 1.6 W /( m 2 · K ). However , the expectation is that the U-value will still have to be much lower than this to enable new dwellings to achieve the target primary energy , carbon emissions and fabric energy efficiency rates , with a window U value of 1.2 W / ( m 2 · K ) referenced in the notional dwelling specification . For replacement windows in existing dwellings , the maximum U value is now 1.4 W /( m 2 · K ), down from 1.6 W / ( m 2 · K ).
Amplified by increased specifier enquiries about the U-values of glass and glazing products , as well as the options for high performance double glazing and even triple glazing , any new glass products will need to demonstrably limit heat loss , whether for old or new dwellings .
Insulating Glass Units ( IGUs ) with higher thermal insulation specifications may be necessary for projects to help prevent heat loss through windows and meet the tighter regulations . These can be installed into many types of existing window frames , and specialist coatings can modify products to better their energy performance during manufacture on-line or subsequently off-line .
Window Energy Ratings ( WER ) are often used as a means of demonstrating compliance with Part L for replacement windows in existing dwellings and considers the total energy performance of a window . The rating doesn ’ t only look at heat loss , but also at the amount of the sun ’ s energy passing through the glazing . As an alternative to the U value compliance route , replacement windows achieving minimum WER band B can satisfy the new requirements .
Thinking one step ahead
2025 will come around quickly , and for new dwellings to meet the targets laid out in the Future Homes Standard in terms of primary energy , carbon dioxide emissions and fabric energy efficiency rates , its fabric elements will need to have U-values even lower than what is set out in the latest version of Part L . It is widely anticipated that the ‘ de facto ’ standard for window U-values in new homes will be 0.8 W / m 2 · K in 2025 .
‘
triple glazing may become mandatory
’
It is important for installers to be prepared for the tightening of these regulations in the run up to the introduction of the Future Homes Standard in 2025 . While triple glazing may become mandatory by then , there are a whole host of other glass and glazing solutions to ensure energy saving and carbon emission avoidance to meet the latest changes .
Solar control glazing allows daylight to pass through a window or façade while reflecting away a large degree of the sun ’ s heat . For example , Pilkington Suncool™ is specifically designed to ensure buildings don ’ t overheat during the warmer months and also helps to reduce the need for both cooling and heating systems .
Where there isn ’ t a need for cooling systems , incorporating a low-e glass such as a glass from the Pilkington K Glass™ Range or Pilkington Optitherm™ S1 Plus helps to prevent heat from escaping through windows , reflecting it back into the building , allowing architects to use more glass .
www . nsg . com
CLEARVIEW-UK . COM JULY 2022
19