The asset
A 14,000 m² A-grade office tower in Auckland CBD, fully tenanted, with a six-year-old building management system that had drifted from its commissioned state. The asset had a NABERSNZ rating of 3.5 stars at the start of the engagement, with a target of 4.5 ahead of a major lease renewal cycle.
What the plan found
The Performance Plan returned 14 ranked opportunities. The first six covered no-capex BMS work: after-hours scheduling, fan curve adjustments, supply-air temperature reset, chilled-water setpoint relaxation, demand-controlled ventilation tuning, and lighting-control schedule corrections. Together, those six accounted for an estimated 18 to 22% of energy reduction with a five-month payback.
What we delivered
Tether ran the BMS work in-house alongside the building’s incumbent controls partner. Sub-metering on three risers was added in month two to support the rating data path. The accredited NABERSNZ assessment was conducted at month seven on twelve months of post-intervention data.
The numbers
- Verified energy saving of $148,000 per year, M&V tracked monthly
- Five-month payback on the no-capex tranche
- NABERSNZ rating moved from 3.5 to 4.5
- Tenant comfort complaints down 34% over the rating period
- Annual M&V is now part of the asset operations rhythm
Why it worked
We did not start with a capex case. We started with what the BMS could already do, freed it to do that, and built the rating data path alongside. The tenant didn’t see disruption. The asset team didn’t see scope creep.
