How has Part L changed the landscape of the industry?

Victoria Brocklesby, co-founder and COO at Origin, discusses the recent changes to Part L and Part F regulations and explores the challenges presented by increasingly stringent guidelines.

Although the recent changes to building regulations have been an ongoing talking point in the fenestration industry, many homeowners will not be aware of these new standards.

So, it’s down to suppliers to provide clear information for customers and support them in making the best decisions for their project.

During these discussions, it’s important to consider the customers’ individual needs and where in the house the doors and windows are being installed.

Part L regulations are just a baseline, so customers looking to prioritise efficiency or those opting to incorporate large expanses of glazing in a room should consider choosing products which beat the current standards on minimum U-values. For those requiring smaller windows, this is less crucial.

Overcoming contradicting regs

Another challenge facing glaziers is how Part L guidelines contradict updated Part F regulations, which dictate the level of ventilation a property must have.

The Part L changes are designed to drive increased thermal efficiency in new homes, but the effect of greater thermal efficiency is reduced ventilation. The new Part F regulations were introduced to counter this, and state that all new properties must have adequate ventilation in order to avoid the build-up of internal pollutants and mould, which can be detrimental to occupants’ health.

These new regulations advise that all new replacement windows are fitted with background trickle vents unless it can be demonstrated that the new windows would not reduce useful ventilation (unlikely given that the thermal efficiency of windows and doors is only going to increase in light of the Part L changes), or that an alternative ventilation system is available.

This new focus on ventilation is at odds with the Part L regulations, which essentially puts the industry between a rock and a hard place. It’s an impossible task for manufacturers and installers to design and install products that are both more thermally efficient and offer better ventilation. So, more consideration is needed by the Government to offer glazing manufacturers and installers clarity on the real priorities for future homes.

On top of these contradicting regulations, there is the challenge of trickle vents being unintentionally misused by homeowners. Trickle vents are designed to be opened for short periods of time to allow temporary ventilation to a room, but it is apparent that they are often left open for much longer periods of time, which is counterintuitive to the benefits offered by more thermally efficient windows.

Preparing for future regs

Whilst the industry has been largely successful in adapting to the latest Part L changes, we’re seeing some manufacturers switching to triple glazing as standard to meet the latest U-values demanded by the new standards. For these manufacturers, meeting the more stringent requirements of the Future Homes Standard in 2025 will be a challenge.

A possible solution suggested by some quarters in the industry is only offering smaller window sizes; thus, reducing cost and increasing thermal efficiency. Smaller windows are common across Europe because they help prevent properties overheating.

However, reducing the size of windows decreases the amount of natural light entering a home, which can have a negative impact on occupants’ wellbeing and mental health. Introducing internal glazing to increase the flow of natural light is a workable solution, but this approach would require increased innovation and a collaborative outlook from architects, builders, and installers to provide feasible solutions for homeowners.

Conclusion

As we approach the Future Homes Standard (2025), there needs to be clarity from the government on the priorities for new homes when it comes to thermal efficiency and ventilation. Manufacturers like Origin will continue to innovate to meet and exceed the ever-evolving thermal efficiency regulations. However, it’s crucial that the industry works together to improve homeowner education to find the best solutions for each property and ensure they are used correctly to optimise efficiency.