The pilot phase of the UK Net Zero Carbon Building Standard (NZCBS v1) closed in September 2026. Of the 42 commercial buildings assessed under the landlord route, the most common failure mode was not energy performance — it was incomplete tenant energy data.
Pass / fail breakdown
- Energy use intensity targets — 64% pass first time.
- Embodied carbon limits — 71% pass first time (where applicable).
- Refrigerant tracking — 88% pass first time.
- Tenant energy data completeness — 31% pass first time.
The lease problem, again
Without green lease clauses requiring tenant energy data sharing, multi-let assets cannot evidence whole-building performance to the NZCBS standard. Updating the precedent lease is the lowest-cost intervention with the highest assessment impact.