Q. What’s your opinion about spray foam insulation for New Zealand homes? A. Spray foam can be used with good results if properly designed and installed well—but a successful outcome requires both of these or a lot of luck. In the UK, there have been enough problems with bad installations of spray foam in retrofitted roof insulation that it impacts …
MBIE releases technical guidance on operational carbon
I welcome the release of technical guidance for operational carbon calculations by MBIE, as part of its Building for Climate Change programme. There is lots of work ahead of us but it’s an important step to have a document to argue about now. In short, the methodology calculates energy use by predictive energy modelling and uses a badness factor (annual …
Kids suffer when schools are poorly designed
Some solid work has been done in Aotearoa New Zealand by very capable architects and Passive House designers to design classrooms to Passive House performance levels. The fact none have yet been built is a sad reflection on prevailing attitudes in the Ministry of Education. Mechanical ventilation for consistent fresh air is getting stripped out at the so-called value engineering …
New thermal bridge requirements in US will influence NZ
There are new thermal bridging requirements being rolled out in the US, of which ASHRAE has just summarised. ASHRAE standard 90.1 is for all new buildings excepting low rise housing and the 20220 version introducees many changes to improve energy efficiency. Fun (?) fact: there are many thousands of different Building Codes across the US. However, 90.1-2022 is a core …
Retrofitting wall insulation is not risk-free
This article from the BBC discusses claims cavity wall insulation installed as part of a government retrofit scheme has led to homes filled with black mould. The installer has gone into liquidation and the industry body guaranteeing the work is blaming the residents of these 1960s-era blocks of flats. I feel for the folks living in those homes. I have …
All homes need mechanical ventilation
I was happy to see this lovely article on a very high-performance home down in Greymouth but I take issue with the last sentence, which implies that mechanical ventilation is needed because this house is special. Yes, this home requires mechanical ventilation … but so do all homes in New Zealand that have windows you can close. That’s been known …
Better building design improves sleep
Sleep is super important for good health and a good life. We know this but generally overlook how building design choices impact sleep quality. An ASHRAE Journal article just published cites an Australia study which estimated the overall cost of sleep disorders in 2019 and 2020 to be USD$35.4 billion! “[T]he financial cost component was USD$10.0 billion … comprising health …
Filtering out fine particulates increases life expectancy
Indoor air filtration capable of reducing PM2.5 particles increases life expectancy and experts argue should change standards to require better filtration. In general, the filters in ventilation equipment are primarily designed to protect the equipment and not to make the air better for those who breathe. There are exceptions, such as the F7 filters in the Passive House-level MVHR systems, …
Scotland sets example for new building performance
Commit to the outcome then work out how to get there, argues Andy Marlow, a leading Australian Passive House designer and former APHA board member. In a recent essay on The Fifth Estate, he highlights how the Scots decided all new builds needed to perform to the Passive House standard—before working how what it would cost or how to pay …