We go to great lengths to maintain the certified level of MVHR efficiency in the high-performance building projects we consult on. We recommend or specify cross-counter flow heat exchangers with well insulated boxes, short exterior air ducts (also well insulated) and semi-rigid or rigid distribution ducting inside the thermal envelope; with all that, projects often achieve 80-90% overall efficiency (ie …
Interior condensation should be expelled from school
If Leaky Buildings 1.0 was about rain getting in where it shouldn’t, then Leaky Buildings 2.0 is all about the build-up of condensation, such that it feels like it’s raining inside. Building physics knows how to build schools that stay dry inside. But here we have another school with a roof that drips on the kids inside due to interior …
BRANZ sees the light on mechanical ventilation
Holy sh*t. Talk about a big shift in perspective. Let’s repeat that: “BRANZ now recommends that residential buildings are mechanically ventilated and are built to an airtightness target.” This comes from an article in the Oct 2020 edition of Build magazine, available online. In it, Senior Building Performance Engineer Greg Overton says “the measurements [from their latest research] sit alongside …
Technical guidance for Formance SIP in Passive House projects
SIP manufacturer Formance has released a technical bulletin for designers focused on how to specify or calculate Formance panel performance for certified Passive House projects. The bulletin is based on a report by Sustainable Engineering. The values provided on the Formance website (for an overall wall assembly with air surface film resistance and cavities) can’t be directly entered into PHPP. …
Green co-leader backs Passive House and co-housing
Great to see Tim Ross of Architype guiding James Shaw around the building site of the Dunedin co-housing project. When this project is completed next year, it will (if it meets the certification standard) jump us up to over 50 Certified Passive House dwellings in New Zealand. If we can use this template to guide our social housing design and …
Focus on performance not just appearance in the Christchurch rebuild
Christchurch City Council’s urban design team has turned in a report that looked at 46 housing developments built since new rules were introduced in 2016 to allow for greater housing density in that city. I had a complicated reaction when I read Christchurch mayor Lianne Dalziel’s quote, “…nothing is going to excite me about a blank wall or a high …
Passive House happy hour: Fast, factual, fun
Don’t already know about this? You’ve got some fun and learning to catch up on. This weekly gig is in its sixth month now, bringing Passive House experts together from around the globe. Most of the presentations are fairly technical and get into the details us Passive House geeks love. The live calls happen at 11 am each Thursday, which …
Mechnical ventilation is a no-brainer
Fresh air is good for people but also the buildings I grumble about BRANZ, but the scientists working there are good people trying to fix problems with how we build. Unfortunately they are hamstrung by needing to do that while not changing how we build. That’s pretty much impossible. How about instead we just fix the Building Code? Proper …
Even a ‘green grid’ has a carbon cost
We can’t solar panel our way out of climate change: energy demand must fall as well. And especially in the winter, when less solar energy is available! This alone is reason to construct energy-efficient buildings that need little energy for heating, and retro-fit those already built. NZ grid emissions, predicted to 2050 Our grid’s carbon emissions are expected to drop, …