How to Achieve Building Regulations U-values

With a UK legal requirement set to achieve Net Zero carbon emissions by 2050, significant changes are occurring to our built environment. Regulatory interim values are being introduced in a bid to enhance the energy performance of both new and existing dwellings in line with the Future Homes Standard.

More specifically, updates to Part L Building Regulations (conservation of fuel and power) will dramatically alter the future of building work. Professionals across the construction industry will need to start implementing low carbon heating systems, along with building upgrades such as energy-efficient window and door systems to futureproof properties.

When was Part L of the Building Regulations Introduced? A Regulations Revision Timeline

With considerable change set to be introduced under the new Part L Building Regulations, it is important to understand the timeline of developments:

February 2020 - Part L Building Regulations 2020 introduction of consultation to establish what key updates would be required.
April 2021 - Secondary consultation completed and closed for Building Regulations amendments
December 2021 - Part L Building Regulations 2021 updated and published along with Approved Document F (Ventilation).
June 2022 - Uplifts to Part L and Part F Building Regulations come into force.
Spring 2023 - Technical consultation on the proposed specification of the Future Homes Standard.
2024 - Future Homes Standard Regulations to be completed.
2025 - Latest Part L Building Regulations come into force as part of the Future Homes Standard.

With revised Part L Building Regulations coming into effect in 2022. Dwellings built from this point forward will need to produce 31% less carbon emissions and serve as a stepping stone to the more ambitious targets of the Future Homes Standard.

Building Regulations Part L insulation standards will undoubtedly play a key role in enhancing energy performance. At the same time, specifying building elements including windows shall also be crucial for making marginal yet valuable gains.

Part L Building Regulations windows requirements

In order for window specifiers to select the right products, they must first come to terms with the new conditions of compliance. Importantly, the U-value requirements for windows and doors will need to be reassessed in line with regulatory changes.

From 15 June 2022, the target U-value for windows in new build dwellings will tighten to 1.2W/m²K and the limiting U Value (for SAP calculation method) set at 1.6W/m²K.

For doors consisting of over 60% glazing the target U-value will be 1.2W/m²K, and 1.0W/m²K for others with limiting value of 1.6W/m²K.

Furthermore, windows and doors in New Dwellings are required to be sealed with membranes and/or EPDM products which improve airtightness.

Replacement windows must have a maximum U-value of 1.4W/m²K or a B for its window energy rating (WER).

Futureproof windows

To support window specifiers in this period of change, it is important to have compliant products readily available. The REHAU TOTAL70 window and door system already surpasses the relevant Building Regulations due to the enhanced thermal properties of PVCu. It is through this manufacture that the range minimises heat loss and easily achieves an A+ rating WER for thermal efficiency.

REHAU TOTAL70 can therefore be specified for the most demanding new-build and refurbishment projects as regulations come into effect. For Passivhaus installations, the company’s GENEO tilt-turn system is also available as a fully certified window and door solution.

Further specifications

What should also be kept in mind among window specifiers are the changes to Part F in relation to building ventilation. When approaching new build projects, background ventilation may be required for less airtight dwellings. Here, REHAU’s latest trickle vent solution is complete with a split closure plate for partial opening when allowing fresh air into the property.

Background ventilators will also need to be considered in replacement schemes. As replacement windows are likely to increase the airtightness of a dwelling, this could limit ventilation rates if a mechanical system is not in place. In these instances, the requirement for trickle vents will need to be assessed to ensure ventilation provision is no worse than before.

A pillar of support

With a host of regulatory updates to take into account, it is essential that window specifiers are fully supported throughout this process. As well as providing high-performance products, it is equally important that suppliers offer guidance in achieving compliance.

It is with this in mind that REHAU’s commercial technical team can be on hand to assist with any design questions, as well as supporting the specification process. Businesses can also benefit from a free CPD to ensure their specification team fully understands how to meet new legislative requirements for windows and doors.

For more information, contact the REHAU team at fhsenquiries@rehau.com or via telephone on 0161 7777444.