Table of Contents
- What You'll Need Before You Start
- Step 1: Set Your Energy Efficiency Targets and Compliance Pathway
- Step 2: Meet BASIX Requirements for Apartments Without Over-Specifying
- Step 3: Model Thermal Performance and Unlock NatHERS Star Rating Benefits
- Step 4: Bring In ESD Consulting for Developers Early
- Step 5: Align Reports With Final Plans and Submit to Council
- Common Mistakes That Delay Energy Efficiency Approvals
- Frequently Asked Questions
Last Updated: September 13, 2026
What You'll Need Before You Start
Energy efficiency for multi residential projects is the practice of designing and documenting a building so it meets the thermal, water and greenhouse targets set by the planning system before construction begins. Getting it right starts with paperwork, not modelling software.
Before you brief anyone, assemble the following:
- Current architectural drawings (site plan, floor plans, elevations, sections)
- The relevant council's DCP and any precinct-specific controls
- Your proposed construction type (masonry, lightweight, concrete)
- Glazing schedule, including frame type and glass specification
- A target completion date for the development application
- Confirmation of whether the project is BASIX-assessable or NatHERS-assessable
Most delays trace back to missing documents, not difficult modelling. Most delays trace back to missing documents, not difficult modelling.
Step 1: Set Your Energy Efficiency Targets and Compliance Pathway
Decide the compliance pathway before you design, not after. In New South Wales, most residential apartment developments go through BASIX, while individual dwellings and some low-rise configurations use NatHERS (Sustainability standards for residential development (BASIX)). Getting this wrong means starting the thermal model again.
Work through three questions:
- Is the development classified as residential flat buildings, shop-top housing, or something else?
- Does the council require a BASIX certificate, a NatHERS certificate, or both?
- Are there local DCP clauses that exceed the state minimum?
Answer those, and you have your target. Skip them, and you'll over-specify glazing to compensate for a pathway you didn't need.
The NSW Department of Planning BASIX guidance sets out which developments require a certificate, and it's worth reading before your first design meeting rather than after.
Step 2: Meet BASIX Requirements for Apartments Without Over-Specifying
BASIX requirements for apartments are performance targets, not prescriptions. The certificate sets minimum scores for water, thermal comfort and energy, and how you reach them is a design decision.
The trap is treating every score as a reason to upgrade every material. A project that hits its thermal target with better orientation and shading may not need the double glazing someone assumed was mandatory.
What works in practice:
- Model the base design first, then improve the weakest element
- Prioritise shading and orientation over material upgrades
- Check whether a commitment already in your DCP satisfies the target
- Confirm the certificate matches the design you'll actually build
Over-specification is a budget problem, not a compliance problem. It passes assessment and costs you money on site.
Step 3: Model Thermal Performance and Unlock NatHERS Star Rating Benefits
NatHERS star rating benefits are straightforward: a higher rating means a building that needs less mechanical heating and cooling, which reduces ongoing running costs for occupants and strengthens your development application. The rating comes from accredited thermal modelling software, not from a rule of thumb.
The modelling itself is where projects gain or lose money. Small changes to window size, eave depth or wall construction can shift a rating more than an expensive appliance upgrade. A common mistake is commissioning the model too late, once the design is locked, leaving no room to adjust.
Bring the model forward. Test two or three design variants early and pick the one that hits the target at the lowest build cost.
Step 4: Bring In ESD Consulting for Developers Early
ESD consulting for developers works best when it starts at concept stage, not at documentation stage. Ecologically sustainable development advice covers thermal performance, water, energy, materials and waste, and it feeds directly into the compliance documents council will assess.
An ESD consultant who joins at concept can flag:
- Orientation problems before they're built into the plan
- Glazing ratios that will fail thermal targets
- Opportunities to meet targets with cheaper construction methods
- Coordination issues between the architect, builder and energy assessor
Joining late, the same consultant can only document what already exists. That's the difference between a project that saves money and one that just ticks boxes.
Step 5: Align Reports With Final Plans and Submit to Council
The report that goes to council must match the plans that go to council. Every time. A certificate referencing superseded drawings is the fastest route to a request for further information.
Run this check before lodgement:
| Check | What to Confirm | Consequence If Missed |
|---|---|---|
| Drawing revision | Report and plans share the same revision number | Submission rejected, resubmission required |
| Glazing schedule | Glass and frame spec matches the model | Certificate invalid |
| Orientation | North point consistent across all documents | Thermal model inaccurate |
| Commitments | Every stated commitment appears on the plans | Conditions imposed at determination |
| Certifier details | Accredited assessor named correctly | Certificate not accepted |
Work through the table once, and you'll catch the errors that cause most delays. The NatHERS administrator guidance on accredited assessments explains the assessor and documentation requirements in more detail.
If you'd rather not manage that coordination yourself, House Energy Certified handles BASIX, NatHERS and ESD documentation as a single package, with reports aligned to your final plans before they leave our desk.
Common Mistakes That Delay Energy Efficiency Approvals
Most approval delays come from process errors, not technical failures. The modelling is usually fine. The paperwork isn't.
The mistakes we see most often:
- Modelling too late. By the time the design is fixed, there's no room to adjust cheaply.
- Generic reports. A certificate that ignores your specific design features gets questioned at assessment.
- Spec changes after certification. Any change to glazing, orientation or construction invalidates the report.
- Assuming every target needs an upgrade. Many are met through design, not materials.
- Leaving ESD advice until documentation. The savings are gone by then.
Each of these costs time. Two of them cost money as well.
Frequently Asked Questions
What are the current NatHERS requirements for multi-residential developments?
NatHERS assesses thermal performance of individual dwellings, and most jurisdictions now require a minimum 7-star rating for new homes and apartments. For multi-residential projects, each apartment must be modelled separately, and common areas may also need attention. The rating considers climate zone, orientation, insulation, glazing and shading. Meeting the minimum is not enough for good outcomes; targeting a higher star rating can reduce heating and cooling loads, which supports both compliance and long-term liveability. Confirm the exact requirement with your assessor before design freeze.
How does BASIX compliance impact multi-residential project timelines?
BASIX is a NSW planning requirement, and a BASIX certificate must accompany your development application. If the certificate does not match the final architectural plans, council can reject the application or request changes, adding weeks to your timeline. To avoid delays, engage a BASIX assessor early, keep the design stable through the assessment, and update the certificate if plans change. Projects that submit a complete, accurate BASIX certificate typically move through council without energy-related hold-ups, keeping your schedule on track.
What are the benefits of achieving a high NatHERS star rating for developers?
A higher NatHERS star rating reduces the energy needed to heat and cool each apartment, which can lower residents' bills and make the development more attractive to buyers. It also helps you meet BASIX and NCC requirements with less risk of last-minute changes. From a cost perspective, better thermal performance can reduce the size of heating and cooling systems, potentially saving on capital costs. Many developers find that targeting a higher rating early avoids expensive retrofits later.
How can ESD consulting reduce build costs in multi-residential projects?
ESD consulting for developers focuses on integrated design decisions that improve energy performance without over-specifying. By modelling options early, consultants can identify cost-effective measures such as improved glazing, shading or insulation that reduce reliance on mechanical systems. This can lower both construction and operating costs. Early involvement also prevents redesign fees and delays caused by late compliance failures. The goal is to meet requirements efficiently, not to add unnecessary features.