The latest building regulations and certifications


Parts L - Conservation of fuel and power

Building Regulations Part L covers the conservation of fuel and power in the building of new homes in England, and establishes how energy-efficient new and existing homes should be. From 15 June 2022 an important update to the Building Regulations will take place which includes an uplift to Part L.

Current Thermal Performance compliance levels for windows and doors. (England) – Nov 2022

Building Regulation (Approved Document L - Conservation of Fuel and Power) compliance levels for Windows and Doors for England changed on 15th June 2022.

• Maximum U-Values for replacement products are now 1.4 W/m²K.

• Whilst limiting U-Values for new fabric elements in new buildings are 1.6 W/m²K for windows and doors, the building element will have to be better than the value stated in table 4.1 of the regulations* to achieve the target fabric energy efficiency rate for the whole building. The value of 1.6 for windows and doors is a potential trade-off for using very thermally efficient materials elsewhere in the building. However, windows and doors with a greater than 60% glazed area should have an overall U-Value of 1.2 W/m²K.

WER vs U-Values

Alternative compliance can also be achieved via an approved Energy Ratings scheme

• Windows: WER Band “B” or better

• Doors greater than 60% glazed area: DER Band “C” or better

• Doors less than 60% glazed area: DER Band “B” or better.

Energy Ratings introduced into the building regulations do not directly correlate with U-Values, they are two different methods of compliance. It is a common misunderstanding throughout the industry that people often confuse energy efficiency with thermal efficiency. Windows with higher WER ratings offer good energy efficiency – but this does not automatically mean that they are any more thermally efficient.

U-Values measure how well the window is working as a thermal insulator – the lower the U-Value, the greater in thermal efficiency performance. WER ratings are used for replacement windows and doors and are not accepted for new build compliance; the initial concept of the WER scheme was to allow consumers and specifiers to compare competing products using a simple and easy to understand ratings and labelling system. The WER energy rating is an energy balance of positive contributions from solar gain minus the negative factors of thermal heat loss and air leakage.

Part F - Ventilation

Part F of the Building Regulations 2010 provides guidance on building ventilation, including building air quality and preventing condensation in domestic or non-domestic buildings. Ventilation is simply the removal of 'stale' indoor air from a building and replacing it with 'fresh' outside air.

Part O - Overheating

The overarching goal of Part O is to encourage the design and construction of buildings that limit unwanted solar gain during the summer months, and provide occupants with adequate means of removing excess heat from indoor environments.

UKCA Certification

UK Conformity Assessed

CE to UKCA Transition

The new UKCA (UK Conformity Assessed) Marking scheme has been operation since January 2021. However, to allow businesses time to transition, the implementation was delayed. UKCA is designed to mimic CE (mirroring BS EN 14351) over all industries and sectors, meaning there will be little change and that it will generally operate in the same manner as CE Marking. Under the UKCA Marking scheme, only U-Values are acceptable in showing compliance - window (WER) and door energy ratings (DER) are not suitable.

From the 1st January 2023 the UKCA mark must be shown. Whiteline is and has been for some time fully UKCA compliant and all relevent Markings appear on the appropriate paperwork.

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