Briary tool suite
Briary Toolsuite
Free calculators for UK building energy compliance, built around the Approved Documents and the questions that come up first on a project.
Enter what you know, read the result with the method shown, and take the report into the design conversation. None of the tools replaces a project-specific assessment, a building-control agreement or professional design advice.
Browse the toolsFree project tools
Choose the check that helps now
- Part L · Fabric Window U-value calculator Whole-window U-value from the glazing, frame and spacer data, calculated to BS EN ISO 10077-1. Uw result · PDF report Open tool
- Part L · Solar PV PV Suite What Part L requires, what fits on the roof, what it generates, how much is used on site and what it is worth. Five-stage workspace · PDF report Open tool
- Part L · Extensions Extension calculator Compare glazing and fabric choices for an extension in England and see how each affects the compliance route. Route comparison · PDF report Open tool
- Part G · Water efficiency Part G water efficiency calculator Both Approved Document G routes from one fittings schedule, with flow-rate measurement built in. Litres per person per day · PDF report Open tool
- Part S · Electric vehicles Part S EV charging calculator How many charge points and cable routes a scheme needs under Approved Document S and regulations 44D to 44J. Provision schedule Open tool
- Part F · Background ventilation Part F trickle vent calculator Background ventilator equivalent area for System 1 under the 2010, 2021 or 2026 edition of Approved Document F. Equivalent area per room Open tool
- Part F · Purge ventilation Purge ventilation calculator Openable area for purge ventilation, room by room, under the 2010, 2021 or 2026 edition of Approved Document F. Openable area per room Open tool
- Part L · Solar PV PV apportionment calculator Equation 5.3 of Approved Document L Volume 1, 2026 edition, dividing a building's ground floor area between the dwellings inside it. Per-dwelling allocation Open tool
- Project · Site Local authority finder Identify the local authority and administrative area for a site from a full UK postcode. Authority details Open tool
No tools match that search. Try a topic such as ventilation, water or PV.
How the tools work
Three steps from question to report
Each tool covers a defined early question and may simplify the underlying method. The result depends on the information entered. Briary confirms any formal route from the project location, documents and applicable requirements.
Pick the check
Filter by topic or search for the regulation, then open the tool that matches the question on the project.
Enter what you know
Each tool asks only for the inputs its method needs, with field help explaining where the figures come from.
Take the result forward
Read the answer with the method shown, download the report and send it to Briary when a formal route is needed.
Send the project information
Include the relevant drawings, location and project stage. We will validate the route and confirm the information required.