Homestar. Technical Manual. Version (February 2016)

Transcription

1 Homestar Technical Manual Version (February 2016)

2 Homestar v3 Technical Manual Thank you to the principal sponsor of Homestar v3: New Zealand Green Building Council (NZGBC) Unauthorised use of Homestar, including this manual, will violate copyright and other laws, and is prohibited. All text, graphics, layout and other elements of content contained in Homestar and its rating tools are protected by copyright, trade mark and other laws.

3 Contents Homestar v3 Technical Manual Contents Contents The Homestar Technical Manual What is in the Homestar Technical Manual? Using the Homestar Technical Manual Introduction to Homestar Aims and Objectives of Homestar How Homestar Rates Types of Homestar Assessments Types of Homestar Professionals The Homestar Process Registration Administration and Audit Fee Assessment Assessment Submission Administration Auditing How Homestar Works Eligibility The Homestar Scorecard and the Multi-Unit Summary Understanding the Homestar Technical Manual Categories Weightings and Calibration Star Bands Mandatory Minimum Levels Resource Adjustment Factor Deeming Credits Not Applicable Credit Interpretation Requests (CIRs) Technical Clarification (TC) Project Inquiries (PIs) The Homestar Tool Definitions ENERGY, HEALTH AND COMFORT EHC-1 Space Heating... 32

4 Homestar v3 Technical Manual EHC-2 Hot Water EHC-3 Lighting EHC-4 Whiteware and Appliances EHC-5 Renewable Energy EHC-6 Whole House Thermal Performance EHC-7 Moisture Control EHC-8 Washing Line EHC-9 Sound Insulation EHC-10 Inclusive Design EHC-11 Natural Lighting WAT-1 Rainwater Harvesting WAT-2 Internal Potable Water Use WAT-3 Greywater Reuse WST-1 Construction Waste Management WST-2 Construction Waste Reduction WST-3 Household Recycling Facility WST-4 Composting Facilities MAN-1 Unwanted Features MAN-2 Security MAN-3 Home User Guide MAN-4 Responsible Contracting MAT-1 Materials Selection MAT-2 VOCs & Toxic Materials STE-1 Stormwater Management STE-2 Native Ecology STE-3 On Site Food Production STE-4 Site Selection STE-5 Common Area Facilities INN Innovation Governance and Quality BRANZ New Zealand Green Building Council Beacon Pathway Homestar credibility Robust technical standards Updates and feedback Feedback on Homestar

5 Contents Homestar v3 Technical Manual 7 Authorisation and Disclaimer Acknowledgments Version 3 update Original development Appendix Appendix Appendix Appendix

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7 Homestar v3 Technical Manual Introduction 1 The Homestar Technical Manual The Homestar Technical Manual is a process and technical guidance document which has been created to aid Homestar Assessors when guiding new builds and major renovations, as well as when carrying out Homestar Certified Ratings. 1.1 What is in the Homestar Technical Manual? An introduction to Homestar. Information about the star bands. Process information about being a Homestar Practitioner and Assessor. Guidance for carrying out a Homestar Design Rating and Built Assessment. Background information about the environmental issues addressed by the tool. 1.2 Using the Homestar Technical Manual The Homestar Technical Manual and the information detailed herein has been designed for, and is to be used by, trained and accredited Homestar Practitioners and Assessors. 1

8 Introduction 2 Introduction to Homestar Homestar v3 Technical Manual Homestar is a comprehensive, national environmental rating tool that evaluates the environmental attributes of New Zealand s homes. Homestar allows owners and tenants to assess their dwelling, providing a scale that creates value around warm, healthy, sustainable and efficient dwellings. Homestar rewards and recognises improvements in both the dwelling s comfort, as well as the likely impact that the dwelling has on the environment. The rating tool was developed by a Joint Venture between BRANZ, Beacon Pathway and the New Zealand Green Building Council (NZGBC) for existing and new dwellings in New Zealand. It is now operated solely by the NZGBC. Homestar is based on a number of successful international rating tools and the approaches they have taken, however it has been developed for New Zealand s specific conditions in consultation with a Technical Advisory Group (TAG) made up of industry experts from across the building value chain. For further details on the TAG please refer to the Acknowledgements section. Version 3 of the Homestar tool and this manual are applicable to all types of residential dwellings including detached houses, apartments and terraces. See Eligibility Criteria (Section 7.1.1) for more details. 2.1 Aims and Objectives of Homestar The overarching objective of the Homestar rating tool is to improve the performance and reduce the environmental impact of new and existing New Zealand dwellings, making them warm, healthy, comfortable places to live. To achieve this objective, the Homestar rating tool aims to: 1. Establish a common language and standard of measurement for efficient, comfortable, healthy dwellings; 2. Reduce the environmental impact of New Zealand dwellings; 3. Provide advice enabling the building and construction industry to produce targeted solutions that deliver results for owners and tenants. 4. Create a value proposition for investment into the attributes that improve the performance of New Zealand dwellings, by rewarding good design with a higher star rating. 5. Raise awareness of the benefits of sustainability for owners and tenants and the construction industry; 2.2 How Homestar Rates There are two types of Homestar assessments an informal online self-assessment and a formal certified rating. An online tool is also available, which owners and tenants to gain an understanding of how their dwelling might rate. A formal rating carried out by a Homestar Assessor shows exactly how the dwelling rates. 2.3 Types of Homestar Assessments Online Tool (Homestar self-assessment tool) An online tool is available allowing owners and tenants to gain a better understanding of their new or existing dwelling and how it is likely to perform in terms of energy, health and comfort, water, waste and more. The online tool takes approximately 20 minutes to go through and produces a short report indicating a provisional Homestar rating on a 1-10 star scale. Most existing New Zealand dwellings achieve between 1 and 5 stars. In addition to providing an indicative rating for the dwelling, the report includes a list of recommendations to help owners and tenants understand how they can make improvements to their dwelling and move up to a higher star rating. Each recommendation can be considered with respect to each of the following priorities: Materials costs Installation costs 2

9 Homestar v3 Technical Manual Points potential Health and comfort Cost savings Environment Introduction At the end of the report the owner or tenant is offered the opportunity to independently contact solution providers who can deliver these improvements Certified Tool A Homestar Built Rating is an official confirmation of how well a home is, or will perform against the Homestar criteria. The Certified Tool comprises of this Homestar Technical Manual and the Homestar Scorecard and Homestar Calculator. There are two checkpoints in the progress of achieving a Homestar Built Rating however these checkpoints are not compulsory. Homestar Appraisal A Homestar Appraisal occurs when a project is at concept phase. It is primarily a marketing opportunity for the developer to confirm intention to achieve a Homestar Built Rating. Homestar Design Rating A Homestar Design Rating is a full assessment of a proposed dwelling based on detailed plans, specifications and any other documentation required to fully describe the build. The documentation that is required for the Design rating is specified in the technical manual. A Design Rating is only a checkpoint on the path to a Homestar Built Rating and will expire after two years from the date being issued. Homestar Built Rating A Homestar Built Rating involves a physical check of a completed dwelling by the Homestar Assessor. It can be conducted on an existing property without a prior Homestar Appraisal or Homestar Design Rating. If a Homestar Design Rating has been completed, the documentation may be used to streamline the documentation process for a Homestar Built Rating. This in-dwelling assessment and the resulting Built Rating, allows prospective buyers and tenants to understand the likely level of performance for a given dwelling and easily compare it to other certified dwellings Homestar online tool (Homestar self-assessment tool) versus Homestar certified tool Both the Homestar online and Homestar Certified Tool derive from the same framework and tackle the same key issues. The Homestar online tool is a simplified version of the Homestar Certified Tool. The purpose of the online tool is to indicate a preliminary Homestar Rating to owners and tenants and provide simple high level advice. The online tool has been created with ease of use as a primary objective in order for it to be highly accessible for owners and tenants. The Homestar Certified Tool has been created to be used by a qualified Homestar Assessor to allow them to verify the attributes of a dwelling. As a result, the Homestar Certified Tool is more detailed than the Homestar online tool. Questions are asked within the Homestar online tool and these questions are designed to identify key information about the dwelling, allowing a preliminary rating to be determined. Points are awarded (or not) behind the scenes of the Homestar website depending on how the online questions are answered. The online tool only gives an indication of how the home will rate and cannot be used for promotional purposes. 3

10 Introduction 2.4 Types of Homestar Professionals Homestar v3 Technical Manual Homestar Practitioner A Homestar Practitioner can assist in the design or building of Homestar projects. They have access to this Homestar Technical Manual and have a good understanding of the Homestar process and credits. Homestar Practitioners are well placed to advise developers and building owners on design features, but are not able to submit Design or Built Ratings to the NZGBC for audit Homestar Assessor Homestar Assessors are independent professionals who are trained and accredited to perform Homestar Certified Design and Built Ratings. The role of the Homestar Assessor is to use the Homestar Certified tool. To qualify as Homestar Assessors they have to complete specific training, pass examinations and carry out supervised ratings. Homestar Assessors are contracted to the NZGBC and carry out rating assessments according to the Rules and Methodology specified by the Homestar Certified Tool. The role of the Homestar Assessor is to use the Certified Tool and carry out assessments of dwellings against the criteria in the Homestar Technical Manual, as well as to support owners in understanding how Homestar works and its purpose. 4

11 The Homestar Process Homestar Technical Manual Version 3 3 The Homestar Process 3.1 Registration The first step in the Homestar process should be the registration of a project with the NZGBC. This allows the NZGBC to become aware of the project s existence and thus to provide help and guidance as required throughout the lifecycle of the project. To register a project with the NZGBC either the Homestar Assessor, or another person associated with the project, needs to complete the Homestar Registration Form (downloadable from the Homestar downloads section of the NZGBC website) and submit it via to the NZGBC at residential@nzgbc.org.nz. 3.2 Administration and Audit Fee Registration with NZGBC prompts the commencement of an administration and audit process associated with the project. For new buildings there is one fee for the appraisal, design and built rating. For existing projects the fee only covers a built rating. A number of factors influence the calculation of work associated with administering and auditing a project and thus the cost of the audit and administration fee. These include: Administration connected to a project is composed of a base level of work which is fixed for all projects, and a variable level of work depending on number of dwellings, therefore the number of dwellings in a project influences the amount of admin work as each dwelling receives an individual rating Audit work is only influenced by the number of typologies audited For the purposes of audit work, a typology can be classified as the floor plan/area/layout assessed in the worst orientation as a minimum Typologies in better orientations could feasibly yield better Homestar ratings so if the project wants a range of ratings rather than a minimum rating, additional typologies will need to be included. There are nominal additional costs for a number of extras. These include the following: Energy modeling Innovation credits Project Inquires (PI) Credit interpretation requests (CIRs). NZGBC s pricing policy is on the NZGBC website and may be updated from time to time. For complete clarity, a calculator is also provided for Homestar Assessors to calculate the administration and audit fee payable to NZGBC. Two variables are necessary for the calculator: number of dwellings in a project and number of typologies being submitted for audit (consider that the client may require not only the worst orientation of a typology, but also the best orientation discuss with the client prior to registration). Once the NZGBC receives a completed registration form (including the number of dwellings requiring a certification and the number of desired typologies for audit), an invoice is raised for the relevant Administration and Audit fee. Once payment is received, a Homestar Registration Letter is issued with a Homestar registration number. This document can be used in support of resource consent applications if required. The turnaround time on the issuance of a Homestar Registration Letter and Number is two weeks from the receipt of payment. 3.3 Assessment Following registration, a project has a number of opportunities to submit documentation and market their progress publicly. For new buildings there is one fee for the appraisal, design and built rating. Project teams do 5

12 The Homestar Process Homestar Technical Manual Version 3 not need to complete an appraisal or design rating but the fee associated with that project will not change. For existing projects the fee only covers a built rating Appraisal (new builds only) A project (new builds only) may choose to ask their Homestar Assessor to undertake a Homestar Appraisal on their dwelling(s). A Homestar Appraisal may only be submitted by a Homestar Assessor. To undertake an Appraisal the Homestar Assessor must review the current drawing set and specification against the Homestar Credit Criteria from the Technical Manual. Typically this drawing set would be about a Resource Consent level of detail. When undertaking an Appraisal, the Homestar Assessor will determine whether or not the project s design is on track to achieve a credit. If the project appears on track for a credit, points are awarded for this credit in the Appraisal. When the Homestar Assessor has completed the Appraisal they must submit it (i.e. the Homestar Scorecard and Homestar calculators), along with the drawing and specification set that they reviewed, to the NZGBC for audit. The NZGBC must complete the check before the Appraisal results can be promoted. The NZGBC turnaround time for Appraisal audit comments is two weeks from receipt of the submission Design Rating (new builds only) A project (new builds only) may choose to ask their Homestar Assessor to undertake a Homestar Design Rating on their dwelling(s). A Homestar Design Rating may only be submitted by a Homestar Assessor. To undertake a Homestar Design Rating the Homestar Assessor must review the Building Consent (or later) design drawings and specifications against the Homestar Credit Criteria from the Technical Manual. The Homestar Assessor must use the guidance in the Assessment tables for each credit and personally sight each piece of documentation that proves compliance with the Credit Criteria before they can award points. When the Homestar Assessor has completed the Design Rating they must submit it, along with all the audit documentation, to the NZGBC for audit and ratification. The NZGBC turnaround time for Design Rating audit comments is two weeks from receipt of the submission Built Rating All projects must undertake a Built Rating. A Homestar Built Rating is an official confirmation of the dwellings design and construction and provides a measured rating for both existing and new homes. As with the previous assessment types a Homestar Built Rating may only be submitted by a Homestar Assessor. To undertake a Homestar Built Rating the Homestar Assessor must review the physically complete property against the Homestar Credit Criteria from the Technical Manual. The Homestar Assessor must use the guidance in the Assessment tables for each credit and personally sight each piece of documentation that proves compliance with the Credit Criteria before they can award points. When the Homestar Assessor has completed the Built Rating they must submit it, along with all the audit documentation, to the NZGBC for audit and ratification. The NZGBC turnaround time for Built Rating audit comments is two weeks from receipt of the submission Built Rating Streamlining Where projects have gained a Homestar Design rating, and also wish to achieve a Built rating, the submission process has been streamlined to acknowledge the evidence already submitted for the Homestar Design rating. This enables projects that have been awarded a Design rating to attain a Homestar Built rating more easily. Currently, a lot of the documentation submitted at Built stage is identical or very similar to that submitted at Design stage, so for credits where this is the case we will enable streamlining. 6

13 The Homestar Process Homestar Technical Manual Version 3 Under Built rating streamlining, if the design of the building (as assessed and audited in the Design rating stage) has been constructed with no significant changes that would affect compliance with the credit criteria, then Homestar Assessor can claim this credit is streamlining at Built Rating submission stage. Here is a list of credits eligible for Homestar Built Rating streamlining: EHC-3 EHC-5 EHC-7 EHC-8 EHC-9 Lighting Renewable Energy Moisture Control Washing Line Sound Insulation EHC-11 Natural Lighting WAT-1 Rainwater Harvesting WST-3 WST-4 MAN-2 Security STE-1 STE-4 STE-5 Household Recycling Facility Composting Facilities Stormwater Management Site Selection Outdoor Common Area Facilities For credits which are claimed as streamlining credit, Homestar Assessor needs to indicate this in on the scorecard and provide any relevant documents (e.g. photos) to demonstrate that credit is eligible for streamlining. If there have been significant changes that would affect the awarding of points, then it is necessary to submit full Built Rating documentation as outlined in the Technical Manual. If there have been design changes that affect the credits, which are deemed to be insignificant by the project team, please list these in the template scorecard explaining the reason. If any credits have had CIRs granted for the Design Rating of the project, then the credit is not eligible for Built Streamlining and full Built Rating documentation as outlined in the Technical Manual should be submitted. If the project team wishes to apply for any points or credits which were not awarded at the Design Rating stage, full Built Rating documentation as outlined in the Technical Manual should be submitted for the relevant credits Projects that haven t been awarded a Design Rating need to submit full Built Rating documentation to get achieve a Homestar Built Rating. 3.4 Assessment Submission When the assessment on a property has been completed the Homestar Assessor must collate all of the required audit documentation into the Homestar Folder Filing Structure ( and submit this to the NZGBC for audit. The Homestar Scorecard contains a self-populating audit documentation checklist that will tabulate all of the information that is required to be submitted to the NZGBC based on what credits have been awarded points during the assessment. Please refer to Appendix 1 for further information on how to compile a good submission. 3.5 Administration NZGBC maintains a database of all Homestar registrations, Design and Built ratings. Each project is tracked and each dwelling receives a Homestar rating. The Homestar rating applies to the individual dwelling (be that a standalone home, a terraced house or an apartment in a building). This individual Homestar rating is used to demonstrate the dwelling s position on the Homestar scale (1-10) and can be used for marketing purposes. 7

14 The Homestar Process Homestar Technical Manual Version 3 Homestar ratings are only uploaded onto the Homestar website public search facility when written permission is supplied to NZGBC. 3.6 Auditing The NZGBC needs to ensure each assessment has been completed accurately and in a manner consistent with Homestar Assessor guidance provided within the Homestar Technical Manual. Consequently please be prepared for all assessments to be audited by the NZGBC at all stages (appraisal, design and built). The general principle applied to audit is that the Homestar Assessor takes responsibility for: Ensuring all documentation is included All documentation is up to date The submission contains the relevant documentation (highlighted or indicated as appropriate) Efficient filing structure to minimise audit time on the submission. The role of the auditor is to check that documentation meets the requirements of the Homestar Technical Manual. The general principles applied to audit are: A complete submission has been supplied with accurate, relevant and precise information Sufficient work is undertaken to ensure documentation meets Homestar Technical Manual requirements Confidentiality of process and handling is important Consistency of process is applied throughout all audits. Once submission documentation has been received, the turnaround time for the initial audit response is two weeks. Should the submission be deemed insufficient or incomplete, the NZGBC will respond with questions. Should a submission be deemed grossly insufficient, the auditor may completely reject the submission without fully scrutinising all credits and request a fresh submission to be completed. After a maximum of two rounds of review, the audit has been completed and the Homestar Assessor is notified of the number of points awarded and a Homestar rating is issued Audit Results Audit results will be provided to Assessors using the following system. There are two audit rounds allowed for in the admin and audit fee. During these rounds the Homestar Auditor will provide responses in the following format. Confirmed For the credit reviewed all required documents have been submitted and, based on these documents, points have been awarded correctly. Confirmed with Comments For the credit reviewed the submission contained documentation or interpretation errors that do not affect the points awarded in the credit, but need to be noted for future assessments. Not Confirmed Submission contains significant errors that affect the points awarded. The Assessor is to review the credit and alter / award points accordingly. If at the end of the second audit round if points still have not been confirmed a Homestar Assessor may apply for a Charged Credit Review. 8

15 The Homestar Process Homestar Technical Manual Version Rating Adjustment If a submission contains a significant number of not confirmed credits a rating adjustment (i.e. change in star rating) may be required. Should this occur this will be reported and recorded against the Assessor. Assessors will be given the opportunity to appeal against the decision at their own cost. When a Built rating requires a rating adjustment, the NZGBC may choose, or the Homestar Assessor may ask the NZGBC, to undertake a physical visit to site to verify that measurements have been taken accurately and consistently. In these instances the NZGBC reserves the right to invoice the Homestar Assessor for the costs involved in completing the site visit. The Assessor will be informed of a site visit and will be given the opportunity to attend. 9

16 Homestar Technical Manual Version 3 The Homestar Tool 4 How Homestar Works This section provides detailed technical guidance to Homestar Assessors to assist in understanding Homestar. This section includes information on: Eligibility Understanding the Homestar Technical Manual Categories and credits Weightings and calibration Star bands Mandatory minimum levels Deeming credits not applicable to a dwelling Credit Interpretation Requests (CIRs) 4.1 Eligibility The Homestar tool (version 2 onwards) allows all types of dwellings to be rated. To be assessed, a dwelling must be considered as being self-contained with the following minimum requirements: One bathroom with toilet and shower or bath One kitchen or kitchen area which must include an oven, a food preparation area and food storage space. 1 The Homestar Scorecard and the Homestar Multi-Unit Summary 4.2 The Homestar Scorecard and the Multi-Unit Summary Introduction The Homestar scorecard enables assessors to conveniently record point awards for various credits, for auditors to confirm/or deny those points and for both auditors and assessors to comment or respond to comments on various credits. It is based on the existing audit template that auditors have been using, and the credit summary in Homestar version 2. One scorecard should be done for each typology. The Homestar Multi-Unit Summary is only used for multi-typology developments and act as a summary of all the points awarded across all the typologies Homestar Scorecard In order to reduce the amount of files that have to be created and submitted the Scorecard has been integrated into the Homestar Calculator. While points for EHC-1, EHC-2, EHC-3, EHC-5, aspects of EHC-6, WAT- 1, MAT-1 and MAT-2 are to be calculated using the available calculator tabs and then entered into the scorecard, points for other credits can be entered directly into the scorecard. For each rating stage (Appraisal, Design and Built), points awarded and confirmed as well as comments are on one page, similar to the current audit template. Thus the auditor can follow the progress of each stage of the project. Each rating stage has its own page. 1 More information about minimum requirements for dwellings, including sizes of kitchen areas (Clause 7) and bedrooms (Clause 8) can be found in the Housing Improvement Regulations 1947, 10

17 Homestar v3 Technical Manual 11 The Homestar Tool Unlike the credit summary in Homestar version 2, all values must be entered in manually, including points calculated on the Homestar Calculator. This is to allow the same calculator file to be used across all stages and audit rounds while ensuring that the points recorded for past auditing rounds do not automatically change. While this is possible in Microsoft Excel, this version of the calculator is simplified to avoid the use of macros to ensure reliability and cross-platform performance. The structure of the scorecard is described in the following sections. Please refer to Appendix 4 for further information including screenshots. Coversheet This is where you can enter general project information, the nature and current stage of the project, as well as the building foot print area, area of conditioned space, gross floor area and the number of bedrooms. It also has some information on the use of the scorecards. Please refer to Appendix 4 for further information. Assessor Worksheet This sheet is for the assessor s use, and can be modified as needed. It is not audited and can be used to write down project assumptions, get feedback from clients, and make notes. It also acts as a summary of required documentation. Appraisal scorecard This is to be used at the Appraisal stage. The assessor is to enter the points claimed in the grey column (Target Points) in the appropriate cell. Where multiple path ways exist to achieving a credit and these have different point structures or total points, a grey cell appears by the credit description which can be modified. Some cells can hold any value (EHC-6), some can only hold certain values (EHC-4) and some only accept a simple Yes/No answer. In general, the grey cells can be modified by assessors and the lime green cells may be modified by the auditor only. The auditor will award some or all of the points in the Point Award column and then select Yes in the All Evidence Sighted Column once all required documentation is sighted and cleared. The auditor will then write comments and these are highlighted using a traffic light system (Green: points confirmed, Amber: points confirmed conditionally, Red: points declined). The final point tally (both targeted and awarded by auditor) and the star rating can be seen at the bottom of the scorecard. The auditor may wish to overwrite the RAF value shown here if they do not agree with the calculated RAF (based on information entered by the assessor). You can also see the mandatory minimums milestones which will help the auditor and assessor see if the mandatory minimums are being met. Design scorecard This is similar to the Appraisal scorecard but is intended to be used the design rating stage. Therefore it covers two audit rounds and the assessor and auditor should take care to enter the points into the correct column. The columns are labelled R1 or R2 for round 1 and round 2. If the auditor awards all of the claimed points for a credit in round 1, they will also be awarded in the round 2 column, and only credits where not all the targeted points were awarded need to be addressed in Round 2. Built scorecard This is similar to the Design scorecard, but differs in that it allows for built streamlining where applicable. Credits where this is enabled will have a box under the BSC column which should be marked with a Y if streamlining is to be claimed. Then once the auditor has seen evidence that is required for streamlining and checked the All Evidence Sighted cell, points awarded in the second round of design rating will be automatically transferred Homestar Multi- Unit Summary This is a summary that maybe used in multi-typology developments where the data from the individual Homestar Scorecards can be entered in as a project wide summary. Only the final credit totals need to be

18 Homestar Technical Manual Version 3 The Homestar Tool entered and comments around if appliances or credit compliance documentation is identical across typologies. This purely serves to help identify such situations for the auditor to help streamline the audit process for larger projects. All values to be entered in manually including the DRAF, and DF. 4.3 Understanding the Homestar Technical Manual Each section of the Technical Manual has a standard structure as follows: Credits Homestar covers six categories. Each of these categories contains a series of credits that are presented within this manual. Each Homestar credit is set out in a consistent manner and incorporates the following: Credit Title Provides the name of the credit. Aim Outlines the purpose of the credit. Credit Criteria Set out the benchmarks, or requirements, for this credit to achieve points. Also gives the maximum number of points available. Assessment Gives instructions for assessing the credit. Audit Documentation Audit documentation is listed separately for both Design Rating and Built Rating. Additional Guidance Provides additional information to assist in assessing the credit as well as providing relevant definitions of Homestar terminology used in the credit. Background Details the environmental issue the credit addresses along with the reasoning behind the approach taken to tackle this issue within Homestar. References and Further Information Provides references to further information on the topic. 4.4 Categories The Homestar tool is divided into six categories: 12

19 Homestar v3 Technical Manual Energy, health and comfort Water Waste Home management Materials Site The Homestar Tool These categories were chosen following a review of international and national rating tools and in discussions with the Homestar Technical Advisory Group (TAG). These categories form the key foundations of Homestar, meeting the aims and objectives outlined in Section Energy, health and comfort The energy, health and comfort category rewards attributes that contribute to reduced energy use within the dwelling, for example energy efficient lighting or energy rated white goods. This category also rewards dwelling attributes that contribute to occupant thermal comfort, for example insulation, or bathroom ventilation that removes dampness from the dwelling Water The water category rewards dwelling attributes that contribute to reduced water consumption, e.g. low water flow taps and toilets Waste The waste category rewards dwelling attributes that provide the ability to readily recycle waste, as well as rewarding construction practices that reduce waste going to landfill Home management The Home management category rewards dwelling attributes that contribute to making a safe, secure and adaptable dwelling Materials The materials category rewards the use of responsibly sourced products and materials that have lower environmental impacts over their lifetime. As well as interior finishes that minimise the detrimental impact on occupant health from products that emit pollutants such as Volatile Organic Compounds (VOCs) Site The site category rewards the attributes of the site such as effective stormwater management, the contribution to local ecology, the ability to grow food on site and the location of the dwelling in relation to key amenities. 4.5 Weightings and Calibration The weight that the Homestar categories have been assigned (i.e. the number of points allocated to each category) has been developed in consultation with the Technical Advisory Group (TAG) and in consideration of national and international precedents set within other relevant frameworks. The weightings of similar schemes, such as the UK s Code for Sustainable Homes and the USA s LEED for Homes, were considered as a starting point for Homestar. The weightings have been fine tuned to reflect the New Zealand built environment and the objectives of Homestar. The Homestar online tool and Certified Tool have been developed with the same weightings. The number of points available within each category and the percentage of total points that each category has within the Homestar online tool and Homestar Certified Tool are shown in the following table. 13

20 Homestar Technical Manual Version 3 The Homestar Tool Table 4.1: Comparison of Homestar online and certified tools Category Homestar online tool (Homestar self-assessment tool) Points available Percentage of total Energy Health and Comfort Points available Homestar certified tool Percentage of total Water Waste Home Management Materials Site Total Innovation 5 5 The above table demonstrates that there are less than 100 points available within the Homestar online tool and therefore the points available within each category are weighted to bring the total up to 100. There is no Materials category within the Homestar online tool. The overall score achieved by a dwelling translates into a star rating. A summary of the star bands is provided in the section below. The majority of Homestar questions/credits are optional. Therefore a dwelling can achieve points in any of the categories above in order to achieve a star rating. However a number of key areas have mandatory minimum levels that must be achieved in order to achieve a particular star rating. These mandatory minimum levels are outlined in Section Star Bands Homestar has been developed to enable both existing and newly built dwellings to undergo assessment. Homestar categories address issues which are not covered in the current Building Code. As such the star bands for Homestar have to cater for a variety of standards of dwelling and their environmental attributes. The star bands have been calibrated so that: A typical house built to the current New Zealand Building Code requirements would achieve between 3 and 4 stars, depending on the number of attributes rewarded within Homestar that are not addressed by the New Zealand Building Code; and A house with a very high level of comfort as well as world best practice in all of the six categories assessed (e.g. substantial renewable energy generation and water management facilities, etc.) could achieve 10 stars. The point scores corresponding to each Homestar star rating are set out below: Table 4.2: Homestar star bands and required scores Rating Required score 1 Star Star Star Star

21 Homestar v3 Technical Manual The Homestar Tool 5 Star Star Star Star Star Star Mandatory Minimum Levels There are some core issues within Homestar that are considered so important that a minimum performance level needs to be achieved before progressing to a higher star rating is possible. These are referred to as mandatory minimum levels. If the assessed house fails to achieve these mandatory minimum levels, no matter what the performance is in other areas of the tool, the minimum levels will limit the final star rating. In this case the dwelling s final star rating will be the highest rating where the mandatory minimum levels are all met. When considering renovations, if possible the owner or tenant should look to address these core issues first, and then reassess the house once the changes have been made. Mandatory minimum levels are in the Energy, Health and Comfort and Water categories and are in place at the 3, 5, 6, and 7 star bands. Apart from these mandatory minimums, Homestar is flexible the owner or tenant can choose which credit criteria to meet. Details of the minimum levels are in the following table. Table 4.3: Homestar Mandatory Minimums Level of achievement Requirement Outcome To achieve 3 stars or above In the Whole House Thermal credit the dwelling must achieve at least 7.6 out of 15 points. If this is not achieved a maximum rating of 2 stars is available. To achieve 5 stars or above To achieve 6 stars or above The mandatory minimum for 3 stars must be achieved. In the Moisture Control credit the dwelling must achieve at least 3 out of 4.5 points In the Whole House Thermal credit the dwelling must achieve at least 10 out of 15 points. The mandatory minimum for 3 and 5 stars must be achieved. In the Internal Potable Water Use credit the dwelling must have dual flush toilets with a maximum 6/3 L/flush) and showers must have a flow of 9L/min or less. To achieve 7 stars or above The mandatory minimum for 3, 5 and 6 stars must be achieved. In the Whole House Thermal credit the dwelling must achieve at least 11.3 out of 15 points. If this is not achieved a maximum rating of 4 stars is available. If this is not achieved a maximum rating of 5 stars is available. If this is not achieved a maximum rating of 6 stars is available. 15

22 Homestar Technical Manual Version 3 The Homestar Tool 4.8 Resource Adjustment Factor A Resource Adjustment Factor (RAF) is embedded within Homestar. The RAF is made up of two components - the Dwelling Resource Adjustment Factor (DRAF) and the Density Factor (DF). These factors are multiplied by each other to determine the overall RAF. The final RAF is then multiplied by the total number of points achieved for the dwelling from the six other categories to determine the final point score. The Homestar Scorecard automatically applies the Resource Adjustment Factor to the dwelling s final point score. Dwelling Resource Adjustment Factor RAF = DRAF DF It is generally recognised that large dwellings consume more resources than smaller dwellings over their lifecycle. Data published by BRANZ shows that an average New Zealand house size has increased markedly over the last two decades (by 65%), while the occupancy rate has dropped from 3.1 to 2.7 persons per house over the same period. The DRAF seeks to account for these impacts in the final point score to encourage less resource intensive designs. The allocation of the DRAF is dependent on the relationship between the house size, measured using the area of Conditioned Space, and number of bedrooms. This DRAF has little impact on the points achieved by an average sized dwelling; however it will reward smaller dwellings over average or larger dwellings. Table 4.4: Dwelling Resource Adjustment Factor 1 Bedroom (m²) Conditioned Space (m 2 ) Thresholds Based on Number of bedrooms 2 Bedrooms (m²) 3 Bedrooms (m²) 4 Bedrooms (m²) 5 Bedrooms (m²) 6 + Bedrooms (m²) Dwelling Resource Adjustment Factor

23 Homestar v3 Technical Manual The Homestar Tool 1 Bedroom (m²) Conditioned Space (m 2 ) Thresholds Based on Number of bedrooms 2 Bedrooms (m²) 3 Bedrooms (m²) 4 Bedrooms (m²) 5 Bedrooms (m²) 6 + Bedrooms (m²) Dwelling Resource Adjustment Factor This DRAF process was modelled on the USA s LEED for Homes (2008) tool. The neutral dwelling sizes (i.e. those houses which have a multiplier equal to 1 in the above Table) were established using a sample of midpriced New Zealand dwelling plans currently freely available on the internet. An average of these dwellings was then taken and extrapolated for the largest sized houses. The DRAF is calculated by interpolations within the Homestar calculator. The maximum DRAF is corresponding to the smallest dwelling sizes listed on the table. Dwellings any smaller will not be awarded a higher DRAF, as homes that are too small may be uncomfortable and uncompliant with building regulations. Density Factor It is also generally recognised that denser urban living is preferable to urban sprawl. To account for this urban living a Density Factor (DF) is calculated in the following manner. The excel tool determines the ratio of the gross floor area to building footprint using the following formula and then looks up the appropriate DF using Table 1. Building GFA building footprint Table 4.5: Land Use Factor Ratio DF Gross floor area of dwelling : Building Footprint

24 Homestar Technical Manual Version 3 The Homestar Tool The DF is then multiplied by the DRAF to determine the overall RAF. The DF has been developed using the theory of ECO: 5 Building Footprint in the Code for Sustainable Homes. The neutral point of the DF is equivalent to the interpolated neutral point of a ratio of 2:1 from the Code for Sustainable Homes which awards 1 point for a ratio of 3:1 and 2 points for a ratio of 4: Deeming Credits Not Applicable Some entire credits, as well as some points within credits, are considered to be not applicable (NA) to some dwellings in some circumstances. These circumstances arise when the attribute or issue addressed by a certain credit, or point within a credit, is not present or relevant to the particular dwelling or site e.g. it is not appropriate to consider dishwasher water efficiency when no dishwasher is present, or construction waste when assessing an existing home. Homestar redistributes points in one of the following three ways when a credit, or point within a credit, is deemed to be NA: 1) Points are redistributed across the remaining points within the credit (effectively increasing the value of the other points available within that credit); 2) Points are redistributed across the category in which the credit is located (effectively increasing the value of the other points available within that category); 3) Points are redistributed across the whole Homestar certified tool (effectively increasing the value of all other points). When credits or points within credits are deemed NA the online and certified tool automatically redistributes the points appropriately. This effectively tailors Homestar to the dwelling being assessed through placing more weighting on those other attributes or issues that can be influenced. The following table outlines the areas within Homestar that can be deemed NA and what happens to those points. 18

25 Homestar v3 Technical Manual Table 4.6: Points available to be deemed as 'not applicable' The Homestar Tool Category Credit and affected points Energy Management Waste EHC-4 Whiteware Appliances MAN-4 Responsible Contracting (2 points) WST-1 Construction Waste Management (3 points) and Not applicable criteria Deemed Not Applicable for dwellings that do not have a dishwasher. Deemed Not Applicable for dwellings that have been in existence for more than 2 years (before the date of assessment) and have not undergone major refurbishment within the past two years (before the date of assessment). Deemed Not Applicable for dwellings that have been in existence for more than two years (before the date of assessment) and have not undergone major refurbishment within the past two years (before the date of assessment. Redistribution methodology Points redistributed across EHC-4 Points redistributed across the whole Homestar tool. Points redistributed across the whole Homestar tool. WST-2 Construction Waste Reduction (3 points) Deemed Not Applicable for dwellings that have been in existence for more than two years (before the date of assessment) and have not undergone major refurbishment within the past two years (from the date of assessment). Points redistributed across the whole Homestar tool. Materials MAT-1 Materials Selection (9 Points) Deemed Not Applicable for dwellings that have been in existence for more than two years (before the date of assessment) and have not undergone major refurbishment within the past two years (before the date of assessment). Points redistributed across the whole Homestar tool. MAT-2 VOC s and Toxic Materials (3 points) Deemed Not Applicable for dwellings that have been in existence for more than two years (before the date of assessment) and have not undergone major refurbishment within the past two years (before the date of assessment). Points redistributed across the whole Homestar tool. Water WAT-2 Potable Water: Dishwasher (0.5 points) Deemed Not Applicable where a dishwasher is not provided in the dwelling. Points redistributed across WAT-2 credit. WAT-2 Potable Water: Clothes washing machine (1.5 points) Deemed Not Applicable where a clothes washing machine is not provided in the dwelling. Points redistributed across the WAT-2 credit. 19

26 Homestar Technical Manual Version 3 The Homestar Tool 4.10 Credit Interpretation Requests (CIRs) It is likely that some dwellings will achieve the intent of certain credits in an alternative manner/approach to that anticipated within the Homestar certified tool. Homestar Assessors are able to submit CIRs when designing/advising on dwellings that are likely to target a Homestar Rating. The Homestar Assessor may submit a CIR to the NZGBC if certainty is required that the alternative approach is acceptable before deciding whether to target a Homestar Rating. Homestar Assessors are also able to submit CIRs to the NZGBC if they conclude that the intent of a given credit is met despite an alternative approach being taken. Please refer to the Homestar website for a copy of the CIR form and details on the CIR process. The approval of CIRs is at the discretion of the NZGBC and a nominal fee is charged (see Homestar Pricing Policy on NZGBC website for details) Technical Clarification (TC) A Technical Clarification (TC) is a query or suggestion for a change to the Homestar Rating Tool or Manual that would affect the whole of Homestar. TCs will be reviewed by Homestar for either immediate approval or consideration during tool review and third party expertise may be sought. Credit Interpretation Requests (CIRs) may be converted into a TC at the discretion of the NZGBC Project Inquiries (PIs) Project Inquiries (PIs) are only to be made by the Homestar Assessor or main contact of a registered project. Each project receives 2 complimentary inquiries, after which a fee of $100 per inquiry will be charged. (see Homestar Pricing Policy on NZGBC website for details). Note that Project Inquiries can take up to two weeks to be processed. The NZGBC may determine that a Project Inquiry is applicable to all projects, and release the proposed response as a Technical Clarification (TC) if appropriate. 20