If the Future Homes Standard goes, accurate U-values must stay

The Conservative Party has pledged to scrap the Future Homes Standard as part of a wider drive to cut housebuilding costs. But Kevin Jones, Technical Director at the Glass & Glazing Federation (GGF), warns that the window and door industry must continue its transition towards more accurate, product-specific U-value calculations, regardless of the political direction of travel.

The Conservative Party’s announcement that it would abolish the Future Homes Standard if returned to government has raised questions about the future of energy efficiency regulation and the investment already made by the UK window and door industry in preparing for it.

Speaking at the Conservative Party conference in Birmingham on 5 October, Shadow Chancellor Andrew Griffith outlined plans to reduce the cost of building new homes by removing regulations the party believes are adding unnecessary complexity and expense to housing delivery.

The Conservatives argue that net zero building requirements are increasing development costs and contributing to higher house prices. Their proposals include scrapping the Future Homes Standard and associated low-carbon heating requirements as part of a wider package of reforms which they claim could reduce the cost of a new home by up to £50,000.

While recognising the opportunity to reduce complexity around the delivery of new homes Kevin Jones, Technical Director, GGF, has argued that regulatory reform should preserve the ambition to deliver warmer, more energy-efficient homes.

Speaking at the Glazing Summit [8 the October], he told an industry audience that even if the Future Homes Standard itself could eventually become a casualty of a change in government, the shift towards product-specific U-values has a compelling justification, in its own right.

An industry already committed to change

He argued that the window and door companies had spent years preparing for the Future Homes Standard, including developing new calculation software, technical procedures and the expertise required to assess the performance of individual window and door configurations.

“There’s been a lot of pain to get where we are as an industry, to the point where we’re starting to bring online all the tools needed to achieve the Future Homes Standard,” he said.

“The change in U-value calculation, moving from a standard size and style to an actual calculation on every single window and door, represents a seismic shift in terms of resource, software and even knowledge of how to do that.

“The underlying principle of more accurate U-value calculations remains essential to improving the credibility of product performance declarations and building performance.” 

How the Home Energy Model transforms window specification

Published in March 2026, the Future Homes Standard introduces a revised regulatory framework for new housing in England, with requirements scheduled to come into force on 24 March 2027, subject to transitional arrangements.

A central element of the government’s longer-term approach is the Home Energy Model (HEM), developed to replace the Standard Assessment Procedure (SAP) as the methodology used to assess the energy performance of dwellings.

HEM is designed to provide a more detailed assessment of how a building performs, accounting for the interaction between its fabric, heating, ventilation and other systems.

For window and door manufacturers, one of the most significant changes associated with the revised framework is the move towards calculating U-values using the actual dimensions and configurations of products supplied to a development – rather than the standard model. 

“The difficulty is that the thermal performance of a window changes according to its size, design and specification” Kevin explained. 

“A smaller window typically contains a higher proportion of frame relative to glass. Where the frame has a higher U-value than the glazing, this increases the overall U-value of the window.

“Similarly, the number of opening lights, mullions and transoms, glazing specification and frame system can all influence the thermal performance of the finished product.

“This creates a potential discrepancy between the U-value calculated for a standard reference window and the performance of a different configuration supplied to a construction project”, he said.

The commercial implications are equally important. Where actual-size calculations produce higher U-values than standard reference figures, manufacturers may need to review frame systems, glazing specifications and product configurations to achieve the required performance.

That could influence the balance between double and triple glazing, the competitiveness of different systems and the cost of supplying windows and doors to new-build developments.

An opportunity for industry to drive up standards

While acknowledging that the Home Energy Model has increased complexity in window and door specification, Kevin argued that it is nonetheless, the right direction of travel for the industry. 

He believes it addresses a fundamental question of whether the thermal performance the industry declares accurately represents the products it manufactures and installs?

“The Future Homes Standard may or may not be scrapped, but the change in U-value calculations will probably still go ahead because it’s about much more than the Future Homes Standard,” he said.

“It’s about increasing the accuracy of what we do. Of course, the whole-house element is a big part of it, but even beyond that, it’s a good idea that we do this anyway.

“The U-values that we’re declaring simply are not what we’re installing.

“How can we sit back as an industry, declaring a 1.2 U-value, knowing what we’re installing is 1.7 or beyond, and say we’re a credible industry that is trying to prove competence and compliance? 

“The two don’t marry.”

A commercial opportunity

The Future Homes Standard assesses the performance of the new homes as a complete system, with the thermal performance of windows and doors contributing alongside walls, roofs, floors, heating and ventilation.

This creates a more direct relationship between the products selected by housebuilders and the ability of a development to achieve its required energy performance.

A window system delivering better thermal performance can contribute to improved whole-building results. Conversely, a product performing below its declared specification can undermine the assumptions used in the building’s energy calculations.

“It creates commercial opportunities for manufacturers capable of delivering consistently strong thermal performance across a wide range of real-world window sizes and configurations”, Kevin continued

Given this, he argues that the priority should be ensuring that the industry’s progress towards more accurate performance declarations continues.

“We’ve invested an enormous amount of time, money and resource in getting to this point, and there are still challenges to overcome,” he said.

“But ultimately, we need to be confident that the information we’re providing is accurate. If we’re declaring a particular level of thermal performance, that needs to reflect the window or door we’re actually supplying.

“There’s a much wider conversation taking place about competence, compliance and the credibility of information moving through the construction supply chain. Accurate U-values are part of that.

“The Future Homes Standard may or may not survive a future change in government. In my opinion, more accurate U-value calculations are here to stay, and they should be.”

For more information about the GGF and how it can support your business, please visit www.ggf.org.uk or call 0207 939 9100.