Renovation Energy Requirements

When Do Renovations Trigger Energy Assessment Requirements?

One of the most common questions homeowners ask is whether their renovation project requires an energy assessment. The answer depends on the scope of the work and the rules in your state or territory. Understanding these triggers early can save time, money, and frustration during the approval process.

In general, energy assessment requirements are triggered when a renovation:

• Adds new conditioned floor area — Extensions that add habitable rooms (bedrooms, living areas, studies) to the home typically require the new portion to meet current NCC energy efficiency standards, including the 7-star minimum.
• Significantly modifies the building envelope — Replacing large sections of external walls, roofing, or windows may trigger compliance requirements for the affected areas.
• Changes the building classification — Converting a garage to a habitable room, adding a granny flat, or subdividing a dwelling can trigger full energy compliance for the converted space.
• Requires a building permit — As a general rule, if your renovation requires a building permit, you should check whether energy compliance is also required. Your building surveyor or an accredited assessor can confirm this.

Common Renovation Types and Their Requirements

Different types of renovations have different energy compliance implications. Here is a guide to the most common renovation scenarios:

Ground Floor Extensions

Adding rooms at ground level is one of the most common renovation types. Ground floor extensions that add habitable space typically require the new portion to achieve a 7-star NatHERS rating (or equivalent). The existing home generally does not need to be reassessed unless the renovation significantly alters the existing building envelope. The assessor models the new rooms, including their connection to the existing structure, to determine compliance.

First Floor Additions

Adding a second storey involves significant changes to the building envelope, including new walls, roof, windows, and often modifications to the existing ceiling (which becomes an intermediate floor). First floor additions almost always trigger energy compliance for the new level and may require reassessment of the ground floor if the existing roof insulation is removed or altered during construction.

Garage and Outbuilding Conversions

Converting a garage, shed, or other non-habitable space into a habitable room (bedroom, study, living area) changes the building classification and triggers energy compliance for the converted space. The converted room must meet current NCC requirements, which typically means adding insulation to walls, ceiling, and floor, and upgrading or adding glazing that meets current performance requirements.

Kitchen and Bathroom Renovations

Internal renovations that do not alter the building envelope generally do not trigger energy compliance requirements. Kitchen and bathroom renovations that replace fixtures and finishes without modifying external walls, windows, or roofing are typically exempt. However, if the renovation involves relocating or adding external windows, or modifying external walls, the altered elements may need to comply.

Renovations That Typically Do NOT Require an Energy Assessment

Many common renovation projects do not trigger energy compliance:

• Kitchen or bathroom renovations that do not alter external walls
• Internal remodelling or wall removal within the existing footprint
• Replacing fixtures, fittings, or finishes
• Painting, flooring, or landscaping
• Like-for-like replacement of windows, doors, or roofing
• Minor repairs and maintenance

If you are unsure whether your project requires an assessment, request a free quote and we will connect you with an accredited assessor who can review your plans and advise on your obligations.

State-Specific Renovation Rules

Each state and territory has slightly different rules about when renovations trigger energy compliance. Key variations include:

• New South Wales — Renovations costing over $50,000 and involving changes to the building envelope may require a BASIX Certificate in addition to NCC compliance. BASIX has specific triggers for alterations and additions.
• Victoria — Extensions and alterations that increase conditioned floor area must comply with NCC energy efficiency provisions. The new portion must achieve the 7-star equivalent.
• Queensland — Renovations are assessed under the Queensland Development Code, which aligns with the NCC but has specific provisions for tropical climate zones.
• ACT — Renovations that increase floor area by more than 25% trigger full energy compliance for the new portion.
• Other states — SA, WA, Tasmania, and NT all follow the NCC framework with local variations. An accredited assessor in your area will know the specific rules.

The Renovation Assessment Process

When you request a quote through ESD Consultants for a renovation project, we connect you with an accredited assessor experienced with alterations and additions. The process typically involves:

1. Scope review — The assessor reviews your renovation plans to determine whether an energy assessment is required and what scope of assessment applies.
2. Existing building documentation — If the assessment requires modelling the existing building as well as the renovation, the assessor may need original plans or may conduct a site inspection.
3. Thermal modelling — The new and (where required) existing portions are modelled in NatHERS-approved software.
4. Design advice — The assessor recommends any changes needed to achieve compliance, often suggesting cost-effective improvements that minimise impact on the renovation budget.
5. Certificate delivery — You receive the compliance documentation required for your building permit. Typical turnaround is 3–7 business days.

Renovation Assessment Costs

The cost of an energy assessment for a renovation varies based on the scope:

• Small extension (under 50m²): $400–$600
• Large extension (50m²+): $600–$800
• Full renovation requiring existing home modelling: $700–$1,200
• Scope determination only: Often free or $100–$200

For more detailed pricing information, visit our energy rating cost guide.

Making the Most of Your Renovation

A renovation is the ideal opportunity to improve your home's overall energy performance. Because walls, ceilings, and floors are already being opened up, the additional cost of energy improvements is significantly lower than retrofitting later. Consider:

• Adding or upgrading insulation in any walls, ceilings, or floors being accessed during the renovation
• Upgrading to double-glazed or low-E windows when replacing existing windows
• Improving air tightness by sealing gaps exposed during construction
• Orienting new living spaces to the north where site constraints allow
• Installing energy-efficient fixed appliances as part of the renovation to meet the whole-of-home energy budget

An accredited assessor can model these improvements and show you the expected star rating improvement and energy savings for each option. For an initial estimate of your project's potential, try our energy rating calculator. When you are ready for a professional assessment, use our find a consultant tool to connect with an assessor in your area, or request a free quote through the enquiry form.