FHS Fabric Specification Lookup
Use this free tool to look up the confirmed U-values and air permeability requirements for new dwellings under the Future Homes Standard. Select a building element to see the limiting and notional values.
For full details on Part L fabric changes, see our comprehensive guide to FHS Part L changes.
FHS Fabric Performance Values
Look up the fabric U-values and air permeability requirements for new dwellings under the Future Homes Standard. Backstop values (the absolute maximum permitted) are unchanged from Part L 2021. The same notional dwelling values apply under both compliance routes (HEM and SAP 10.3); the specification is published as Appendix R of the SAP 10.3 specification and as the dwelling notional buildings document for HEM.
Select a building element above to see its performance requirements.