What Does a Homestar Rating Mean for Your Home?

May 29, 2026

Learn how Homestar improves comfort, efficiency, and health, and how NZCB Studio’s Homestar Ready plans make building a high performing home easier.

When building a new home, many New Zealanders are looking beyond the minimum requirements of the Building Code and thinking more carefully about how their home will perform long term. Comfort, energy efficiency, running costs, and indoor health are becoming increasingly important considerations for homeowners wanting a home that not only looks good, but also feels good to live in every day.

One of the best-known ways to measure this performance is through the Homestar rating system. Developed by the New Zealand Green Building Council (NZGBC), Homestar provides an independent framework for assessing the health, efficiency, and sustainability of homes across New Zealand.

A 6 Homestar rating represents a home that performs significantly better than the minimum standard required by the New Zealand Building Code. In practical terms, that can mean a warmer, drier, healthier home with lower energy bills and improved year-round comfort.

What is the Homestar rating system?

Homestar assesses homes on a scale from 6 to 10 stars, with 6 Homestar considered the entry point for a decent home. The rating looks at how a house is designed and built, evaluating the features that directly affect comfort, efficiency, and environmental impact.

Rather than focusing on one single aspect, Homestar takes a whole-of-home approach. It considers how the home will perform day to day, from temperature control and ventilation through to water use, material selection, and waste reduction.

The goal is simple: to encourage better quality homes that support healthier living while reducing environmental impact and long-term operating costs.

Key areas Homestar assesses

Energy, health, and comfort

One of the biggest focuses of Homestar is creating homes that are comfortable to live in throughout the year. Homes with poor insulation or inadequate ventilation can often feel cold and damp in winter; while overheating during summer months can also become an issue.

Homestar encourages better thermal performance through features such as effective insulation, improved airtightness, quality glazing, and well-designed heating and ventilation systems. Energy efficient lighting and appliances also contribute to the overall rating.

These elements work together to create more stable indoor temperatures, improve air quality, and reduce moisture issues, all of which contribute to a healthier home environment.

Water efficiency

Water conservation is another important part of the Homestar framework. Points are awarded for features that help reduce household water consumption, including rainwater harvesting systems and water efficient taps or showerheads.

Higher rated homes may also incorporate greywater recycling systems and other water-saving technologies that help reduce pressure on local infrastructure lower utility costs and improve resilience.

Waste reduction and sustainable living

Homestar also considers how waste is managed both during construction and throughout the life of the home. Builders can gain points and reduce build costs by reducing construction waste.

Materials and indoor air quality

The materials used inside a home can have a significant impact on indoor health. Homestar rewards the use of eco-labelled and lower toxicity materials, including low volatile organic compound (VOC) paints and finishes that help improve indoor air quality.

This is particularly important in modern homes, where improved airtightness means indoor pollutants can become trapped if materials and ventilation systems are not carefully considered.

Site design and innovation

Homes that work well with their natural surroundings can also gain additional points. Features such as native planting, fruit trees, vegetable gardens, and sustainable landscaping all contribute to a home’s environmental performance.

Homestar also allows for innovation points where homes include features that go beyond standard practice, such as electric vehicle charging capability or advanced energy saving technology.

homestar upgrades graphic — image provided by new zealand green building council

Homestar vs the New Zealand Building Code

The New Zealand Building Code sets the minimum legal standard for residential construction. While this usually ensures homes are structurally sound, minimum compliance does not always guarantee year-round comfort or energy performance.

Homes built only to the minimum standard can still experience issues such as poor thermal performance, dampness, overheating, and higher ongoing energy costs.

Homestar encourages designers and builders to think about performance much earlier in the design process. By considering insulation, orientation, glazing, shading, and ventilation from the beginning, homes can often achieve significantly better performance in a practical and cost-effective way.

The result is typically a home that is warmer, healthier, more energy efficient, and cheaper to run over time.

Can existing homes get a Homestar rating?

Homestar was primarily developed for new builds. It’s often very early decisions about size, shape and amount of glazing that will lock in the performance of a home. These can be harder to change in existing homes.

However, the Homestar modelling tool and design guide are useful for helping with all the decisions during a renovation. Improvements such as better insulation, upgraded glazing, improved ventilation, and moisture management can all make a noticeable difference to the comfort and efficiency of existing homes.

Experienced NZCB builders can help homeowners identify practical ways to improve the performance of an existing property.

Homestar Ready homes through NZCB Studio

To help make good homes more accessible, NZCB Studio now offers Homestar Ready house plans developed in collaboration with Designgroup Stapleton Elliott.

These architect-designed homes provide a streamlined pathway for homeowners wanting to build a healthier, more energy efficient home without starting the design process from scratch.

The plans are designed to meet key 6 Homestar performance criteria. Because the designs are pre-developed and consent ready, homeowners may also be able to move from planning to construction much faster, potentially in as little as eight weeks.

For many families, this offers a practical and cost-effective way to access quality architectural design with performance already built into the plans.

Healthier homes and long-term savings

Building a high performing home is not only about sustainability. It can also deliver meaningful long-term financial benefits.

Research into Homestar rated homes shows that improved energy efficiency and thermal performance can help reduce running costs over time, particularly through lower heating and energy use. Some homeowners may also benefit from financial incentives or improved lending conditions when building more sustainable homes.

Building better with an NZCB builder

A well-designed home is only part of the equation. Achieving strong performance outcomes also relies on quality workmanship and attention to detail during construction.

Choosing an NZCB builder means working with trade-qualified professionals committed to delivering quality homes built to a high standard.

By combining an NZCB Studio Homestar Ready design with an NZCB builder, homeowners can have confidence that their home is designed and built with comfort, durability, sustainability, and long-term performance in mind.

12.1	Part G of the Schedule contemplates that the Parties will elect who is responsible for arranging the contract works insurance. If the Parties have not made that election or if their intention is unclear, then the Owner must arrange contract works insurance if the Building Work involves changes, alterations, renovations, restoration, repairs or maintenance to existing structures, and the Builder is responsible for arranging contract works insurance if the Building Work involves constructing an entirely new stand-alone structure. Irrespective of who arranges the contract works insurance, the excess on a contract works claim is payable by the Owner. Given that such insurance typically expires on Practical Completion, the Owner must ensure that the Building is insured from that point onwards.
12.2	The amount insured must be at least as much as the Original Contract Price, plus an allowance for Owner-supplied materials, expediting expenses, removal of debris, professional fees, increased costs during construction, increased costs during reconstruction, and materials in storage (off the Project site). Unless otherwise agreed, the allowances for these items shall be those shown in Part G of the Schedule, and if no allowance is made in that Part for any item then the allowance must be reasonable in the circumstances.
12.3	The Owner must arrange contract works insurance against loss or damage to the Owner’s existing structures made available by the Owner to enable the performance of the Building Work, or existing structures adjacent to the Building, and to the Owner’s contents. This insurance must be for the full replacement value, and for consequential loss arising from loss or damage to those structures and contents.
12.4	The Builder must arrange public liability insurance for loss or damage to any property, or illness, injury or death to any person, that arises from the performance of the Building Work.
12.5*	In the event of loss or damage to any part of the Building which is not caused by the Builder or any party for whom the Builder is responsible:
	a.	The Builder is not required to carry out any restoration work at the Builder’s own expense.
	b.	The Builder will restore all loss or damage to the Building and the restoration work will be treated as a Variation.
	c.	The restoration work will be paid for from the proceeds of the contract works insurance.
	d.	If the delay in confirming insurance cover after loss or damage to the Building has occurred is such that the Builder can no longer reasonably afford to maintain spare capacity to perform the Building Work when required, the Builder may suspend the Building Work as if clause 20.2 applied, and if the Builder has not cancelled the contract in the meantime, the Builder shall not be obliged to resume the Building Work until the Builder’s commitments reasonably allow for a resumption.
12.6	If this Contract is completed on-line, and either Party has selected the option to apply for a contract works policy marketed under the “REDi” brand, then an application for such a policy will be automatically generated from the information entered into the Schedule of this Contract.
12.7	The insurance broker responsible for arranging the REDi contract works policy and the underwriter(s) to whom the application is submitted together with their respective representatives or agents are authorised to obtain from, and disclose to, any other party any information they consider relevant to the assessment of the application for the policy.
12.8	For the purpose of section 12 of the Contract and Commercial Law Act 2017, the provisions in this Part 12 are intended to create obligations enforceable by the insurance broker and the underwriter(s) referred to in clause 12.7 and their respective representatives or agents, whether or not they are parties to this Building Contract.

4.1	This is a building contract in which the total price payable for the Building Work is not fixed, specified, or known at the time of entering into the Contract. Instead, the progress payments and the Final Contract Price are to be calculated by reference to the actual costs incurred by the Builder in carrying out the Building Work, plus a Margin for the Builder’s Off-site Overheads and profit. The Parties may have chosen to enter into this form of building contract for any number of reasons, including that it is too difficult for the Builder and/or the Owner to accurately predict the precise scope of the Building Work at the outset, or the Building Work involves innovative systems or materials the cost of which is largely unknown, or to avoid the administrative burden of having to recalculate a fixed contract price each time a component of the work changes, or simply because it is their preference to do so. While this inevitably involves some uncertainty as to what the Final Contract Price will eventually amount to, it has the advantage that at the conclusion of the Building Work the Owner will have become liable to pay no more and no less than the value of the Building Work and materials the Owner has actually received.
4.2	The progress payments and the Final Contract Price payable to the Builder shall therefore be calculated by reference to the hours of work expended by the Builder and the Builder’s employees and contractors in carrying out the Building Work, plus the materials and other direct costs incurred by the Builder in carrying out the Building Work, using the rates set out in Part F of the Schedule. Onto those amounts shall then be added the Margins for the Builder’s Off-site Overheads and profit, calculated by reference to the percentages shown in Part F of the Schedule.
4.3	The Builder shall be entitled to charge for and recover all costs that the Builder would not have incurred but for the Building Work, and that are reasonably necessary to carry out the Building Work to the standard required by this Contract, plus the relevant Builder’s Margins. Those costs include (without limitation):
	a.	The Builder’s own labour and labour performed by the Builder’s employees and contractors.
	b.	Products or services from subcontractors or specialist trades.
	c.	Professional advice such as architecture and engineering.
	d.	Building materials and consumables.
	e.	Hireage of tools, plant, equipment, appliances or vehicles.
4.4	The cost of labour shall be calculated using the labour rates set out in Part F of the Schedule, or where no rates have been specified in any particular case, at the prevailing market rates for the personnel in question. The labour rates set out in Part F of the Schedule apply to normal working hours and days, and in calculating working hours no deduction shall be made for work breaks that are reasonably necessary for the consumption of food or beverages or to ensure the continued health, safety, productivity and efficiency of the relevant personnel. Where in order to comply with the Builder’s obligations under this Contract it is reasonably necessary for the Builder and/or the Builder’s employees and subcontractors to carry out Building Work outside of normal working hours or on weekends or public holidays, and the Builder is required to pay penal or overtime rates as a result, those penal or overtime rates shall be included in the calculation of the cost of the Building Work.
4.5	All the costs of the Building Work apart from labour shall be calculated by reference to the invoice issued to the Builder for the relevant item, or if no invoice was issued, by reference to what the Builder actually paid. Where such costs cannot be separately identified or accurately ascertained through timesheets, invoices or otherwise, the cost of those items shall be calculated having regard to the prevailing market price for the relevant items.
4.6	The rates set out in Part F of the Schedule shall be adjusted for any increase in the rates charged by subcontractors that could not reasonably have been foreseen by the Builder at the time this Contract is signed by the Builder, and which would otherwise have the effect of eroding the Builder’s profit margin. The Builder must be able to substantiate the increase by reference to written evidence such as quotations, communications or invoices from the relevant subcontractor, clearly demonstrating the rates that were first advised to the Builder when Part F of the Schedule was completed, and the rates subsequently charged. The Builder shall whenever reasonably practicable, resist any rate increases and procure subcontracts on the basis of fixed rates that cannot be increased during the course of the Building Work.
4.7	If any of the subcontractor rates set out in Part F of the Schedule decrease for any reason (other than rebates or discounts provided to the Builder as a result of such factors as loyalty, volume of business, enticement to form a new or long term trading relationship, or membership of a trade association or cooperative company), the decreased rate(s) shall be used in the calculation of all progress payments and the Final Contract Price from the time that the decrease takes effect.
4.8	Either prior or subsequent to the Parties entering into this Contract, the Builder may have given or may give to the Owner or the Owner’s representative(s) an estimate, indication, projection, guess, intimation, prediction or similar communication (together referred to as an “estimate”) as to what the Final Contract Price or any component of it is likely to turn out to be. It is common for building owners to request an estimate and it is common for builders, in good faith and out of a desire to be helpful, to comply with that request, or indeed to offer an estimate unsolicited. The Parties acknowledge that even the most carefully calculated estimate can in hindsight prove to be grossly pessimistic or optimistic, and it is impossible for the Builder to accurately predict what the final outcome of the Project will be, given that so many factors are outside the Builder’s control.
4.9	The Parties have chosen this form of contract rather than a fixed price contract because they have agreed that the Final Contract Price will be determined by the hours of work and the materials and other direct costs that are ultimately involved, and the margin applied to those items. By definition, those hours and those costs cannot be known in advance. The Parties therefore expressly record that any such estimate that may have been or may be provided by the Builder – assuming the Builder used the term “estimate” or some reasonably equivalent expression – shall only represent the Builder’s best guess, based on the Builder’s experience and what the Builder knows about the Project itself to date. The Builder agrees to take reasonable care in calculating any estimate that may be given, and to keep the Owner regularly informed, by the provision of periodic invoices or otherwise, of the amount paid and payable to the Builder in respect of the Building Work at any given time.
4.10	A price estimate is fundamentally different from an undertaking, promise, commitment, statement, assurance, warranty or representation (together referred to as a “representation”) that the total contract price will amount to, or will not exceed, a stated or fixed sum. If the Builder has given such a representation, then that will bind the Builder in accordance with its terms. However the representation must be reasonably inferred from the wording used. For example if either of the Parties has, without full knowledge of the legal significance, mistakenly described an estimate as a “quote” or used some other wording that might suggest a representation that would be enforceable in law, then that will not constitute a representation if the Parties did not intend it to have that effect.

13.1	Part H of the Schedule contemplates that the Parties will elect who is responsible for arranging the contract works insurance. If the Parties have not made that election or if their intention is unclear, then the Owner must arrange contract works insurance if the Building Work involves changes, alterations, renovations, restoration, repairs or maintenance to existing structures, and the Builder is responsible for arranging contract works insurance if the Building Work involves constructing an entirely new stand-alone structure. Irrespective of who arranges the contract works insurance, the excess on a contract works claim is payable by the Owner. Given that such insurance typically expires on Practical Completion, the Owner must ensure that the Building is insured from that point onwards.
13.2	The amount insured must be at least as much as the Original Contract Price, plus an allowance for Owner-supplied materials, expediting expenses, removal of debris, professional fees, increased costs during construction, increased costs during reconstruction, and materials in storage (off the Project site). Unless otherwise agreed, the allowances for these items shall be those shown in Part H of the Schedule, and if no allowance is made in that Part for any item then the allowance must be reasonable in the circumstances.
13.3	The Owner must arrange contract works insurance against loss or damage to the Owner’s existing structures made available by the Owner to enable the performance of the Building Work, or existing structures adjacent to the Building, and to the Owner’s contents. This insurance must be for the full replacement value, and for consequential loss arising from loss or damage to those structures and contents.
13.4	The Builder must arrange public liability insurance for loss or damage to any property, or illness, injury or death to any person, that arises from the performance of the Building Work.
13.5	In the event of loss or damage to any part of the Building which is not caused by the Builder or any party for whom the Builder is responsible:
		a.	The Builder is not required to carry out any restoration work at the Builder’s own expense.
		b.	The Builder will restore all loss or damage to the Building and the restoration work will be treated as a Variation.
		c.	The restoration work will be paid for from the proceeds of the contract works insurance.
		d.	If the delay in confirming insurance cover after loss or damage to the Building has occurred is such that the Builder can no longer reasonably afford to maintain spare capacity to perform the Building Work when required, the Builder may suspend the Building Work as if clause 20.2 applied, and if the Builder has not cancelled the contract in the meantime, the Builder shall not be obliged to resume the Building Work until the Builder’s commitments reasonably allow for a resumption.
13.6	If this Contract is completed on-line, and either Party has selected the option to apply for a contract works policy marketed under the “REDi” brand, then an application for such a policy will be automatically generated from the information entered into the Schedule of this Contract.
13.7	The insurance broker responsible for arranging the REDi contract works policy and the underwriter(s) to whom the application is submitted together with their respective representatives or agents are authorised to obtain from, and disclose to, any other party any information they consider relevant to the assessment of the application for the policy.
13.8	For the purpose of section 12 of the Contract and Commercial Law Act 2017, the provisions in this Part 13 are intended to create obligations enforceable by the insurance broker and the underwriter(s) referred to in clause 13.7 and their respective representatives or agents, whether or not they are parties to this Building Contract.

9.1	The Builder shall commence the Building Work within a reasonable time after:
	a.	the Contract has been signed by both parties; and
	b.	any deposit payable in accordance with clause 7.2 has been paid; and
	c.	any necessary Building Consent or resource consent or other requisite consents or licences or consent amendments have been issued.
9.2	Unless otherwise agreed in writing between the Parties, the Owner shall obtain all project information memoranda, Building Consents, resource or other consents or licences, and consent amendments required for the Building Work.
9.3	The Owner shall promptly provide all information reasonably required by the Builder to enable the Builder to comply with the Builder’s obligations under this Contract, whether prior to the commencement of, during the performance of, or after the completion of the Building Work.
9.4	The expected completion date stated in Part B of the Schedule shall be automatically extended by a reasonable time where delays arise due to:
	a.	Variations;
	b.	Any strike, lockout, or other industrial action;
	c.	Loss or damage to the Building Work other than loss or damage caused by the Builder’s breach of its obligations under this Contract;
	d.	Flood, volcanic, or seismic events;
	e.	Inclement weather;
	f.	Failure to obtain consent or approval through no fault of the Builder;
	g.	Failure by the Owner to give timely directions;
	h.	Unforeseen physical conditions;
	i.	The Builder exercising its right to suspend the Building Work under this Contract;
	j.	Act, omission or default by the Owner or any person for whose acts or omissions the Owner is responsible;
	k.	A separate contractor’s act or omission;
	l.	Unavailability or shortage of materials;
	m.	Any other event which is beyond the reasonable control of the Builder and for which the Builder is not responsible.

7.1	The Builder is not obliged to commence the Building Work until any deposit payable in accordance with clause 7.2 has been paid.
7.2	The Deposit shall be paid by the Owner upon signing the Contract. The Deposit shall be held by the Builder and applied towards payment of the final invoice, or as provided by clause 20.9 or clause 21.4. The Deposit is therefore not to be treated as a progress payment. If the final invoice is less than the Deposit then the Builder shall pay the Owner the balance of the Deposit upon issuing the final invoice.
7.3	The Owner shall make progress payments to the Builder for Building Work completed and materials supplied, including any adjustments for Provisional Sums, cost fluctuations or Variations, up to the end of the applicable period or stage of work. The payments shall be made into a bank account provided by the Builder via internet banking or direct deposit, unless the parties agree on a different payment method.
7.4	Where the parties have agreed to progress payments at completion stages (Option A in Part E of the Schedule) the Builder may issue an invoice at any time after a relevant stage of completion is reached. If a completion stage cannot be reached due to matters beyond the Builder’s reasonable control, and one month has elapsed since the previous invoice, the Builder may invoice for the proportion of that completion stage that has been reached.
7.5	Where the parties have agreed to progress payments at the end of defined periods of time (Option B in Part E of the Schedule) the Builder may issue an invoice for the Building Work completed up to the end of each such period. Any invoice issued in advance of the end of the relevant period (other than a final invoice) shall be deemed to have been issued on the last working day of that period.
7.6	The Owner must pay the invoiced amount in full within 5 Working Days of the invoice being delivered or sent to the Owner or such other time as is stated in Part F of the Schedule. If the Owner does not consider that all or any part of the invoiced amount is payable, the Owner must, within 5 Working Days after the invoice was delivered or sent to the Owner:
	a.	reply in writing to the Builder stating the amount that the Owner considers payable (the undisputed amount), and
	b.	specifying the reasons why any part of the invoiced amount is disputed, and the method in which the disputed amount has been calculated; and
	c.	pay the undisputed amount.
7.7	If the Builder’s invoice is or is accompanied by a payment claim made under the CCA, then any payment schedule as defined in section 5 of that Act must be provided to the Builder within 5 Working Days of the payment claim being served on the Owner.
7.8	The Owner shall pay progress payments on the due dates, irrespective of when the Owner’s bank or financier is prepared to advance any monies required by the Owner in order to meet the Owner’s payment obligations under this Contract. It is the Owner’s responsibility to ensure that sufficient funds are available to comply with the Owner’s payment obligations under this Contract. The issue of a Code Compliance Certificate is not a prerequisite to Practical Completion or the Builder’s entitlement to payment of the final invoice.
7.9	The Owner may at any time request the Builder to provide a receipt or statement recording or evidencing the payments received from the Owner.
7.10	The Parties will comply with their obligations (if any) under Subpart 2A of the CCA (which requires certain retention monies to be held on trust or otherwise secured) to the extent that Subpart 2A applies to this Contract. The purpose of this provision is to ensure that an adjudicator appointed under the CCA or an arbitrator appointed under the Arbitration Act 1996 has jurisdiction to make a determination in respect of any such obligations, as if they were expressly incorporated into this Contract.

What Does a Homestar Rating Mean for Your Home?

What is the Homestar rating system?

Key areas Homestar assesses

Energy, health, and comfort

Water efficiency

Waste reduction and sustainable living

Materials and indoor air quality

Site design and innovation

Homestar vs the New Zealand Building Code

Can existing homes get a Homestar rating?

Homestar Ready homes through NZCB Studio

Healthier homes and long-term savings

Building better with an NZCB builder

Latest News

What Does a Homestar Rating Mean for Your Home?

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Being a NZCB member is good for business.

The website is undergoing maintenace, please come back later.

Make a technical enquiry

What Does a Homestar Rating Mean for Your Home?

What is the Homestar rating system?

Key areas Homestar assesses

Energy, health, and comfort

Water efficiency

Waste reduction and sustainable living

Materials and indoor air quality

Site design and innovation

Homestar vs the New Zealand Building Code

Can existing homes get a Homestar rating?

Homestar Ready homes through NZCB Studio

Healthier homes and long-term savings

Building better with an NZCB builder

Latest News

What Does a Homestar Rating Mean for Your Home?

The complete guide to building a house in New Zealand

Thinking About Adding a Room to Your Home? Start Here

How to start a building business: A builder’s guide to going out on your own

How to choose a house plan

2026 NZCB Conference & Expo: Register now and save!

Being a NZCB member is good for business.

The website is undergoing maintenace, please come back later.

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4. Calculation of Progress Payments & Final Contract Price

13 Insurance

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