This first study of its kind in New Zealand attempts to calculate how much carbon new homes can emit if we are to stay within the 2 degrees warming limit set by the Paris Agreement—and how much carbon our new builds are actually using. The outcome? Our typical built-to-Code new builds spew out five times more carbon than their fair …
Ireland releases new nearly-zero energy building regulations
Ireland has released its nearly-zero energy buildings regulations (to comply with EU requirements) and insulation supplier Xtratherm has published a guide for builders/designers. I’ve pulled together a table of the minimum performance values and calculated the R-values to help folks in NZ compare. These are average values and include thermal bridging from timber etc. Note that although the climate in …
Embodied carbon/energy—it’s in the floors
I know this seems obvious when you think about timber-framed residential buildings: all the embodied CO2 is in the concrete and steel, so the bulk of it is used in the foundation. But in bigger buildings, it’s not so obvious where the carbon cost is hiding. In a typical commercial building, just over half the embodied carbon is in the …
About time: Damn right, mechanical ventilation is appropriate in all new buildings
Why am I sounding overjoyed at this simple text from BRANZ? The backstory goes a long way back. In its <December 2019 Guideline https://www.branz.co.nz/guideline>, the front story is about smart vapour retarders (SVR) and how they lower the risk of mould in New Zealand wall assemblies. (There’s a story about that too, but that’s for another time.) The big …
2019 October 1 Build: How Airtight Do Houses Need To Be
This article doesn’t really come to a conclusion other than the old rule of thumb of divide the blower door ACHn50 by 20 to determine the average infiltration is not accurate. I know how hard it is to estimate the site wind speed from weather station data and then the pressure across the envelope and of course the ACHn50 number …
2019 September 30 Passive Houses on Energy Efficiency
80-90% heating energy reduction (well for those that could afford to heat their homes) saves energy, CO2 and costs less over the lifespan of the building than building to the legally required minimum (i.e. code). Passive House Pools (Passivhaus) are being built in the UK and were measured to save 70% of the heating energy costs (electricity) in the first …
2019 September 27 AU Codes to Zero Carbon
Built to Perform: An Industry Led Pathway to a Zero Carbon Ready Building Code 3 July 2018 Improved energy performance of buildings presents a win-win-win opportunity, reducing stress on the electricity network, offering bill savings, supporting a least-cost pathway to a zero-carbon built environment, and improving health and resilience outcomes for households and businesses https://www.asbec.asn.au/research-items/built-perform/ Trajectory for Low Energy Buildings …
2019 September 20 ATTMA: Registered Air Tightness Testers – New Zealand
List of all the current air leakage testers in New Zealand accredited with ATTMA. Air leakage testing very tight buildings (as they all should be build tight and ventilate right is a thing after all) can be tricky and the right training makes it much easier. We recommend for your Passive House blower door test: Air leakage testing is done …
Oppose NASH as AS for E2 as it doesn’t cover external insulation
And putting batts between light steel framing is not a good option as discussed below. https://www.mbie.govt.nz/have-your-say/building-code-update-consultation-november-2019 The Oak Ridge National Laboratory has found that thermal bridging in a wood-framed wall lowers the effectiveness of cavity insulation by 10%, but performance drops a whopping 55% in a wall framed with steel. https://www.buildingscience.com/documents/insights/bsi-005-a-bridge-too-far “But from a hygrothermal standpoint, I can only add …