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Consultation document: Insulation requirements in housing and other buildings
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2. Insulation in housing and small buildings
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2.2. Optimising insulation to better balance upfront building costs and longer-term benefits
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Consultation document: Insulation requirements in housing and other buildings
- 1. Introduction
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2. Insulation in housing and small buildings
- 2.1. Background on energy efficiency for housing and small buildings
- 2.2. Optimising insulation to better balance upfront building costs and longer-term benefits
- 2.3. Topic 1: The schedule method may lead to higher upfront costs and less cost-effective construction than the more flexible calculation and modelling methods
- 2.4. Topic 2: The calculation method contains restrictions to the flexibility of roof, wall and floor R-values that can lead to unnecessarily costly and complex construction in some buildings
- 2.5. Topic 3: Where underfloor heating is only used in bathrooms, the minimum R-values for heated floors may cause unreasonable upfront costs
- 2.6. Consistency and certainty of compliance and consenting
- 2.7. Topic 4: The modelling method includes requirements that are unclear or outdated
- 2.8. Topic 5: Thermal bridging from framing in walls is not adequately considered
- 2.9. Topic 6: How the areas of roofs, walls and floors should be measured is unclear
- 2.10. Topic 7: NZS 4214 includes ambiguous instructions for determining the R-values of roofs, walls and some floors
- 2.11. Topic 8: For some mixed-use buildings it is unclear whether H1/AS1 and H1/VM1 can be used, or H1/AS2 and H1/VM2
- 2.12. Topic 9: The look-up tables with R-values for slab-on-ground floors do not cater for some common situations
- 2.13. Topic 10: The look-up table with R-values for vertical windows and doors in housing misses some common glazing types
- 2.14. Topic 11: Acceptable Solution H1/AS1 and Verification Method H1/VM1 include obsolete provisions and definitions, and outdated references to documents and tools
- 2.15. Summary of the proposals for housing and small buildings
- 2.16. Transition period for housing and small buildings
- 2.17. Effects of the H1 insulation requirements on overheating and dampness risks in new housing
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3. Insulation in large buildings
- 3.1. Background on energy efficiency for large buildings
- 3.2. Optimising insulation to better balance upfront building costs and longer-term benefits
- 3.3. Topic 12: The schedule method may lead to less cost-effective construction than the more flexible calculation and modelling methods
- 3.4. Topic 13: The calculation method does not provide flexibility for roof, skylight and floor R-values, limiting opportunities for optimising insulation
- 3.5. Topic 14: Where underfloor heating is only used in bathrooms, the minimum R-values for heated floors may cause unreasonable upfront costs
- 3.6. Consistency and certainty of compliance and consenting
- 3.7. Topic 15: The modelling method includes requirements that are unclear or outdated
- 3.8. Topic 16: The schedule method does not adequately limit heat losses and gains from skylights in large buildings
- 3.9. Topic 17: Thermal bridging from framing in walls is not adequately considered
- 3.10. Topic 18: How the areas of roofs, walls and floors should be measured is unclear
- 3.11. Topic 19: NZS 4214 includes ambiguous instructions for determining the R-values of roofs, walls and some floors
- 3.12. Topic 20: For some mixed-use buildings it is unclear whether H1/AS1 and H1/VM1 can be used, or H1/AS2 and H1/VM2
- 3.13. Topic 21: The look-up tables with R-values for slab-on-ground floors do not cater for some common situations
- 3.14. Topic 22: Acceptable Solution H1/AS2 and Verification Method H1/VM2 include obsolete provisions and definitions, and outdated references to documents and tools
- 3.15. Summary of the proposals for large buildings
- 3.16. Transition period for large buildings H1/AS2 and H1/VM2
- 3.17. Transition period for large buildings H1/AS2 & H1/VM2
- Appendix A: Proposed changes to Acceptable Solution H1/AS1 Energy Efficiency for all housing, and bu
- Appendix B: Proposed changes to Verification Method H1/VM1 Energy Efficiency for all housing, and buildings up to 300m squared
- Appendix C: Proposed changes to Acceptable Solution H1/AS2 Energy Efficiency for buildings greater than 300m squared
- Appendix D: Proposed changes to Verification Method H1/VM2 Energy Efficiency for buildings greater than 300m squared
2.2. Optimising insulation to better balance upfront building costs and longer-term benefits
Three key topics that cover ways insulation could be optimised to better balance upfront building costs and longer-term benefits.
On this page
2.2.1. Topics identified
The upfront cost of insulation in buildings is offset by ongoing benefits including reduced heating and cooling bills, and improved occupant comfort. There are differences to the degree to which the three compliance methods enable designers to optimise insulation levels for a particular building and strike the right balance between upfront building costs and long-term benefits.
Recent sector engagement and BRANZ analysis identified that:
- Topic 1: The schedule method may lead to higher upfront costs and less cost-effective construction than the more flexible calculation and modelling methods.
- Topic 2: The calculation method contains restrictions to the flexibility of roof, wall and floor R-values that can lead to unnecessarily costly and complex construction in some buildings.
- Topic 3: Where underfloor heating is only used in bathrooms, the minimum R-values for heated floors may cause unreasonable upfront costs.