Future Homes Standard: What Joinery Manufacturers Need to Know

The publication of the Future Homes Standard marks one of the biggest changes to window and door specification for new homes in recent years. While the headline U-value for windows remains 1.2 W/m²K, the way compliance is demonstrated has changed significantly.

The new standard takes effect from March next year, sooner than many expected; the usual extended time for projects in progress has also been cut through changes to the rules. So expect to be asked to meet the new regulations now when quoting for new build projects. We’re on hand to help you with this.

Key Changes

• Every new-build window must be assessed individually, based on its actual size, configuration and components, rather than relying on a standard reference window.
• The new Home Energy Model (HEM) replaces SAP calculations for new homes, requiring an area-weighted average based on the windows actually installed.
• Window features such as transoms, mullions, dummy sashes, Georgian bars, add-on cills and head vents will now influence thermal calculations.
• Smaller or more complex window designs will become more challenging to achieve the required performance, potentially increasing demand for higher-performance glazing, including triple glazing in some applications.
• Manufacturers will need software and manufacturing systems capable of calculating and evidencing the thermal performance of every window supplied.
• The new requirements apply to new-build housing only. The current approach for replacement windows remains unchanged, although the GGF believes similar requirements could extend into the replacement sector in the future.
• The regulations take effect from 24 March 2027 for most new-build projects in England, with later implementation for higher-risk buildings and limited transitional arrangements for projects already in the pipeline.

Why It Matters

The Future Homes Standard represents more than a change in thermal targets. It introduces a new approach to compliance that places greater emphasis on accurate product data, certified systems and digital calculation tools. Manufacturers who prepare early will be better placed to support developers and maintain specification confidence as the industry adapts.

Does this Affect Extensions?
No. The new Home Energy Model and individual window calculations apply to new-build dwellings. Extensions and replacement windows in existing homes continue to follow the current Part L requirements. However, the GGF believes this could be a stepping stone towards similar performance-based assessment of replacement windows in the future.

Lignum Perspective
Lignum manufacturers already benefit from independently tested, certified window and door systems, with ongoing development of digital tools to support the evolving requirements of the Future Homes Standard. As compliance becomes increasingly data-driven, system-based manufacturing is expected to provide significant advantages in demonstrating product performance and reducing specification risk.

U-values for Every Window

Both our software partners, Joinerysoft and CalWin, already have Lignum solutions for individual U-Value calculations that, based on the new standard guidance, should be compliant.

Glass & Glazing Federation

The GGF offers valuable insights to The Furture Homes Standard and we are working closely with them within the new Timber Windows & Doors Technical Group, Chaired by TJN member John Grant, MD of GK Joinery Ltd. If you do any new-build work,

it’s well worth checking out this article by GGf Technical Director Kevin Jones: Future Homes Standard Delivers Step-Change for Windows & Doors