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Why are the Irish standards not current? Why is that not explained in this document. Why are the English and Welsh standards different from those shown in BRANZ research?
Insulation is also about health and mould
Why have you chose to publish English & Wales individual element minimum ratings, rather than the model building ratings in table 4?
Is this comparison correct, as per https://www.linkedin.com/pulse/mbie-misrepresent-building-code-targets-damien-mcgill/
What about heat loss through infiltration?
Sorry - that is incorrect English insulation values are R7.7 for roof and floor.
Are the background analysis documents available, and from where? e.g. to better understand the modelling assumptions made to develop the various requirements?
Irish window values are 0.71 according to BRANZ.
Can you explain a bit more about where the investment figures come from? Assumptions etc
I suggest a change in emphasis. Rather than a clumsy insulation rate regardless of size of building, how about taking into account the external surface area for number of people accommodated. - so bigger more vacuous houses have to have much higher insulation levels all around
If the current 'performance based' code was working, would the Superhome Movement need to exist?
What about airtightness, thermally broken windows installed within the thermal envelope, ventilation?
We shouldn’t kid ourselves that this will do much for climate change when most heating is either carbon neutral wood or 90% renewable electricity, heading to 98% renewable well before the 50 year age of building. Heating energy is often seen as a proxy for low carbon - but as BRANZ found heating energy is actually the least important. “Plug” loads and Embodied Carbon most important. A lot of houses are heated with wood fires and the rest by electricity that is rapidly heading to 100% renewables.
Like the example of double glazing, if you mandate it, very quickly suppliers, builders etc will find a way to make it happen.
All the way. Very quickly. We're ready!
Why are the costs of construction documented, but only the percentage of energy saving shown. Why aren’t the energy savings costed?
why do we need 25 degrees, Have you considered that normal people just put on more clothes in winter - so insulate the body rather than the building
Wonder if MBIE have considered that new products being updated/developed to meet the Code will have associated R&D costs that will have to be added onto the product cost. Therefore pushing costs onto end-user.
25 degrees is the upper limit before we hit overheating. Insulation prevents overheating as well as excess energy use. 25 degrees is not a target in the heating season
@matt Abercrombie - those products are already on the market and being used across Aotearoa.
What's the R&D required @Matt? We just need to catch up.
Matthew, Andrew Alcorn found in his doctoral Thesis that there is a point of diminishing returns on the climate impacts of putting in more insulation - you don’t have to get much above current code minimum before the amount of climate emissions you are saving by having more insulation is overuled by having higher carbon emissions in the insulation (and structure). The big thing is not energy efficiency it is carbon emissions.
Bigger issue will be ensuring that the specification doesn't suffer from product substitution.
Its not just about carbon emissions, its also about warm, dry healthy homes... ones that don't make you sick.
Agree with you last pont Peter
I've run numbers and found quite a bit different solution than Andrew Alcorn found in his doctoral Thesis. I found that even Passive House levels of insulation in NZ was not over-insulated. This is similar levels to option 3. See https://sustainableengineering.co.nz/life-cycle-analysis-shows-ph-performance-still-the-right-choice/
More natural light will result in larger windows and therefore less insulation. What is being proposed to upgrade the windows in apartments?
How do we ensure that these Code changes are evaluated for wellbeing benefits - given that, this is the current Government and Treasury metric? There are health, productivity, learning and education, etc. from the changes.
@Matthew Cutler-Welsh, much of the R&D costs involve modifying high performance overseas suites to get them through other sections of the code.... for example E2/AS1, or face other massive expenses getting alternative solutions. That one section is changing without the others changing to suit...
Great question @Teena
This is an excellent initiative that can make a positive difference to our energy use and comfort levels if we get it right. The more homes we build to these levels the more efficient we will become at building them. Let's go NZ!
@Nick to which of the three levels?
Why don’t MBIE set out a roadmap for change to 2050 so that everyone knows where we are heading longer term and can plan for this?
@Damien I'm referring to the overall direction of the initiative. One thing missing at this point is to simply measure energy efficiency (in kilowatt hours (energy use) per m2 per year) right from the start, but I'm sure the voice of the industry will be loud and clear on this during the consultation phase ;)
What about thermal bridges? As you increase the insulation levels, thermal bridges take on a greater and greater significance
Really need to dumb 4214
Agree with that Damien, a roadmap is what's urgently needed. However from what I understand they don't know what that roadmap looks like and think it will be years in development itself, so are launching this as a quick fix. As per Nick I agree that at least it's heading in the right direction...
@Nick good point, Government should require the Power Co to monitor and report on the Kw hr / m2 for all dwellings. Sure they will need to gather m2 for each metered power but it will give us great data.
Replace 4214 with ISO 6946 as a minimum
MBIE are answering the Q&A
Carbon as a metric still needs to be taken more seriously in order to meet our obligations under the Zero Carbon Act.
@Damien McGill There is no requirement for "more" natural light. The proposed documents are new methods for demonstrating compliance with the existing G7 requirements.
Airtightness is not the future, it is now. You may as well ignore all this talk on insulation performance if you do not resolve airtightness.
Can you give us a link to the draft proposals
can you put the link to the feedback form,?
Here Matthew, https://www.mbie.govt.nz/dmsdocument/13808-consultation-document-building-code-update-2021