Property Developers

SBEM, the Simplified Building Energy Model, is the government's approved methodology for calculating the monthly energy use and carbon emissions of a non-domestic building from its floor area, fabric, conditioning, hot water and lighting. For new buildings it is used to demonstrate compliance with Part L of the Building Regulations at design stage and again as built.

A design-stage BRUKL is required before work starts to show the proposed building complies, and an as-built BRUKL plus the new-build EPC is required at completion to reflect what was actually installed. Building control will not sign off without the as-built submission, so late design changes must be fed back into the model.

The 2021 edition tightened target emission rates substantially for non-domestic buildings, introduced a primary energy target alongside carbon, brought in tougher fabric and services standards, and added photographic evidence requirements for as-built compliance. It is a staging post towards the Future Buildings Standard, so schemes designed to the old edition rarely pass unchanged.

An Energy and Sustainability Statement is a planning document that sets out how a development meets local and national carbon reduction policy, usually following the be lean, be clean, be green, be seen energy hierarchy. Most London boroughs and many other authorities require one before determining a major application.

Ideally at RIBA Stage 2, while orientation, glazing ratios, fabric strategy and plant selection are still open. Energy advice introduced after Stage 4 can usually only add cost, because the cheap carbon savings are locked into decisions already made.

TM52 is the CIBSE methodology for assessing overheating risk in naturally ventilated, non-domestic buildings using three adaptive comfort criteria applied to a full year of simulated data. Planning authorities increasingly require a TM52 assessment to show a scheme will remain comfortable without resorting to mechanical cooling.

TM54 predicts a building's real in-use energy consumption, including small power, catering, lifts, server rooms and out-of-hours operation, none of which appear in a Part L compliance model. It exists to close the performance gap between the regulated figure and the energy the occupier will actually pay for.