CIBSE TM54 Operational Energy Assessments
Walker Energy Analysis carries out CIBSE TM54 operational energy assessments, using dynamic thermal modelling in IES Virtual Environment to predict how a building will actually perform once it’s occupied. Unlike Part L compliance modelling, which compares a building against a standardised notional building, TM54 estimates real-world energy use, covering regulated and unregulated loads, realistic occupancy, and how the building is actually likely to be run.
Design-stage energy predictions routinely undershoot what a building goes on to use once occupied. TM54 exists to close that gap, giving you a more credible energy figure before the building is built, rather than an uncomfortable surprise once it’s occupied.
Why Projects Need a TM54 Assessment
TM54 gets used for a few different reasons, and we scope the work accordingly.
GLA and London Plan submissions: major developments in London need a TM54 assessment submitted through the GLA’s Be Seen platform at planning stage, alongside the Part L comparison. This is a planning requirement, separate from Building Regulations, and also carries a five-year commitment to report in-use energy data once the building is occupied.
BREEAM ENE01: up to four credits are available under ENE01 for Prediction of Operational Energy Consumption, assessed using the TM54 methodology, separate from the BRUKL-based regulated energy metrics in the same credit.
Voluntary performance gap analysis: some clients want a realistic operational energy prediction regardless of any planning or BREEAM requirement, particularly where a net zero or in-use performance target has been set in the brief. We run the same methodology as a standalone assessment in these cases, with sensitivity and scenario testing to identify where design or management decisions have the biggest impact on real energy use.
- Dynamic simulation model covering both regulated and unregulated energy use
- Assessment of unregulated loads that Part L compliance modelling doesn’t capture, including small power, lifts, escalators, EV charging, catering and server rooms
- Scenario and sensitivity testing, showing how different management or design decisions affect predicted energy use
- Reporting formatted for GLA Be Seen submission, BREEAM ENE01, or as a standalone report, depending on what’s needed
- Benchmarking against comparable building performance data
Working at Any Design Stage
Concept design: early benchmarking and target-setting, so the operational energy target can inform decisions on plant strategy and controls while the design is still flexible.
Technical design: full TM54 assessment, ready for GLA planning submission or BREEAM ENE01.
Post-occupancy: GLA submissions carry a five-year in-use reporting commitment. We can support this ongoing reporting alongside the original assessment.
Why Work With Us
We’re a specialist energy consultancy. This is the core of what we do, not a sideline. Every assessment runs through IES VE as standard, we turn changes around quickly, and results come back in a format your team, planning authority, or BREEAM assessor can use immediately.
FAQs
Q: Do I need TM54 for every project?
A: No. It’s a planning requirement for major developments in London, an option under BREEAM ENE01, and otherwise a voluntary assessment for clients wanting a more realistic energy prediction. We’ll confirm which applies to your project.
Q: Is TM54 the same modelling as my Part L compliance assessment?
A: No. Part L compares your building against a standardised notional building using fixed assumptions. TM54 predicts realistic operational energy use, including unregulated loads like small power and catering, based on how the building is actually expected to be run.
Q: Can the same TM54 assessment support both a GLA submission and BREEAM ENE01?
A: Often, yes. The underlying modelling is the same methodology, so where a project needs both, we structure the assessment to support each without duplicating the work.
Q: What’s the five-year reporting commitment?
A: GLA planning conditions for major London developments typically require in-use energy data to be reported for five years after occupation, alongside the original TM54 prediction, so it can be compared against actual performance.
Get a Realistic Energy Prediction Before You Build
Talk to Walker Energy Analysis at design stage, whether TM54 is needed for GLA planning, BREEAM ENE01, or your own performance targets.
Does your project need something else?