How to Read Your BASIX Certificate Commitments (and Build to Them)
A BASIX Certificate is only useful if it is built. Here is how to read the commitments and make sure your project delivers them.
A BASIX Certificate is more than a piece of paper for the council. It is a list of promises, called commitments, that your home must deliver. Understanding and building to those commitments is what turns a certificate into an approved, compliant home. Here is how to read yours.
What commitments are
Commitments are the specific measures your design relies on to meet the energy, thermal comfort and water targets. They cover things like insulation values, glazing types, hot water systems, fixtures and any rainwater tank. They must be shown on the plans and delivered on site.
The three groups to check
| Area | Typical commitments |
|---|---|
| Energy | Hot water system, lighting, appliances, solar |
| Thermal comfort | Insulation R-values, glazing, shading |
| Water | Fixture star ratings, rainwater tank, connections |
Reading it like a builder
- Match every line to the plans. Each commitment should appear on the drawings the builder works from.
- Check the glazing. The window types specified must be what gets ordered and installed.
- Confirm the hot water system. Substituting a cheaper system can break compliance.
- Keep the fixtures honest. Tap, shower and toilet ratings need to match the certificate.
The certifier checks these
During and after construction, the certifier verifies that the commitments were actually built. Swapping a specified heat pump for a basic electric tank, or installing thinner insulation than committed, can hold up your occupation certificate. Build what the certificate says, or have it formally updated first.
If something has to change
Designs evolve, and that is fine. If a commitment needs to change, the certificate should be re-issued to match before construction locks it in. Quietly substituting is what causes problems at final inspection.
Frequently asked questions
What if my builder wants to substitute a product? Check it against the certificate first. If it differs, we can re-issue so the documents stay valid.
Who is responsible for delivering commitments? The owner and builder deliver them, and the certifier verifies them.
Need your commitments explained or updated? Send us your certificate and we will walk you through it.
BASIX & NatHERS specialists, a division of Contrive Consultants. We help NSW homeowners and builders achieve energy-efficient, compliant homes.