Part L 2026 introduces a new functional requirement for providing practicable renewable energy generation (kWh).
The functional requirement is based on renewable energy production of 71 kWh/year/ m² of ground floor area (differs for flats). Though any renewable technology can be used, this value has been based on installing unshaded photovoltaic (PV) panels at a 45° pitch, facing south-east or south-west, with a capacity calculated with an efficiency of 0.22 kWp/m² over 40% of the building’s ground floor area including unheated areas (for flats this is divided by the number of stories).
Both the Regulation and the Approved Document outlines when buildings can deviate from this requirement. This includes:
- Buildings with a storey at least 18 metres above ground level and contains dwelling,
- Approved design limitations or building surroundings impacting renewable energy generation,
- Equivalent offsite renewable energy generation is available to resident use.
Given above we anticipate that many developments will be required to develop evidence the demonstrates what is reasonably practicable.
The dwellings emission rate (DER) and dwelling primary energy rate (DPER) will only be improved if renewable energy generation is greater than generated by the capacity calculation outlined above.