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Building Regulations for Windows and Doors: Parts L and F Explained


27 October 2026

If you’re replacing windows or doors in England, they need to meet Building Regulations.

This guide explains the changes to Part L (energy efficiency) and Part F (ventilation) introduced in June 2022, and what they mean for new and replacement windows and doors.

It’s a helpful read if you’d like to understand why ventilation and energy ratings matter.

It’s general information, so always check with your installer or local building control for your project.