22 Mar 2022

Changes to Part L - Too Far or Not Far Enough

Changes to Part L - Too Far or Not Far Enough

AluK’s very first podcast in October 2021 was on the topic of Part L – asking representatives from across the industry to contribute to a debate about the expected changes and the impact these were likely to have on the window and door market.

Now that the new Regulations have been published, with a reduction in notional U-Values for windows and glazed doors in new build homes to 1.2 and limiting U-Values of 1.4 for replacement windows and glazed doors in existing homes, AluK has gone back to some of those podcasters and asked them what they make of the new rules and whether they think they go far enough.

From AluK’s point of view, Head of Process and Certification, Dale Pegler said: “The changes are broadly in line with what we were anticipating, albeit with a few surprising additional amends within the released document. However, AluK is already well on the way towards ensuring we have a full range of product options which comply with the regulations. We would perhaps have liked to see some mention of the assessment of embodied carbon in construction materials, because environmentally, this is just as significant as thermal performance – and of course, aluminium is a 100% recyclable material.”

Mark Taylor, Technical Director at architects Allies and Morrison, welcomed the lowering of the U-Values in the notional dwelling, but shared the view that the changes could have gone further. He said: “The U-Value of 1.2 represents only a small improvement on where we are now, but we can all see the direction of travel. At least there’s a bigger incentive now for architects to calculate the psi value (which is heat loss per metre at the edge of the glass) and that’s a more accurate reflection of the true performance of the window.”

By contrast, Gareth Allen, Technical and Training Manager at Saint-Gobain Glass, felt that the pace of change is probably about right in terms of moving towards the government’s target of a 30% reduction in carbon emissions from new homes. He said: “What came out of AluK’s podcast was an acknowledgement that some sectors will find it harder than others to comply even with this fairly conservative shift to 1.2 for new dwellings and 1.4 for existing.

“Saint-Gobain Glass is certainly committed to doing our part to support the whole industry on that journey, and we’ve already got products available which will help with compliance, and we’re seeing a return to normal stock levels.”

John Miles, from Assent Building Control, agreed that, given the fragility of the construction sector at the moment, the new Regulation will deliver the right amount of progress at just about the right pace.

One thing he pointed out though was the relative lack of pushback from the industry on the changes, suggesting perhaps that many had actually expected the notional U-Values to be lower. He did say that, in practice, many architects are likely to specify U-Values for windows which are lower than 1.2 if they are using SAP calculations to balance glazing with the overall efficiency of the building fabric. This, he added, is likely to lead to more widespread use of triple glazing in new build, very much in line with the thinking during the podcast.

John also warned that the transitional arrangements are not as generous as many people think, stating: “Only plans for projects which have already been approved are likely to come outside of the new rules. In reality, fabricators and installers will need to be making the changes now ready for projects which start after June 15.”

Kevin Jones, the GGF’s Technical Officer, confirmed that the Federation is in contact with the DLUHC to give feedback on the published document, but remained confident that the industry will rise to the challenge.

AluK will be announcing a series of special Part L update events for customers this month and already has a dedicated Future Homes Standard web page at: https://www.alukgb.com/learning/fhs

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