Easier ways to gather data to predict mould growth

Modelling mould growth in domestic environments using relative humidity and temperature is a useful technical paper, as it seeks to modify the VTT model of mould growth on surfaces to make it easier to use in built homes. The research also suggested the existing VTT model underestimates the risk of mould in domestic settings.  The authors surveyed a large number …

Fine particulate pollution is terrible for human health

Today I learned that lymph nodes are heavily impacted by air pollution. This photo shows lymph nodes specifically associated with the lungs and how they are affected by air pollution as we age. It’s gruesome. I already knew fine particulates were bad, but this image has visceral impact and I’ll strengthen the advice I give to clients about how to …

Design Passive House for your individual client

Should Passive House designers be doing more to design buildings that avoid summer overheating? This article from mainstream business magazine Forbes considers Bahnstadt, a Passive House district in Heidelberg, Germany. The story quotes residents who were struggling to stay comfortable as summer temps soared in 2023.  The two residents have different motivations for living there and different experiences of their …

Morning Report: why are NZ homes so damn hot right now?

Morning Report rang me this week for comment about overheating homes, in the face of record temperature spikes. You can listen to the short segment here, or there’s a print version also. For the physics geeks, here is how I worked out the numbers I provided about emissions. I used an average grid emissions factor of 0.12 kgCO2e per kWh …

New free tool for exploring climate files

I’ve discovered a climate file exploration tool that will be really useful for Passive House designers. Best, it’s open source, so free to use. This is particularly timely given the promised update to the climate files we currently use for Passive House design in Aotearoa. What we currently access contains 30 years of climate data—but NIWA compiled those files 20 …

In the race to net zero, operational carbon remains crucial

Lloyd Alter is a Canadian adjunct professor and writer on sustainability topics. Like a growing number of commentators, Lloyd is brushing off the impact of operational carbon and arguing for the need to radically focus on lowering embodied carbon: building with low carbon building materials and methods that are low or zero carbon and retrofitting and renovating existing buildings rather …

Stepwise energy improvements waste time and money

Neil Savery had a 20 year career with the Australian Building Codes Board, nine years as its CEO. Let’s say that gives him some perspective, and industry experience worth listening to. In a story on Fifth Estate, he’s quoted as saying that Australia would have done better to ‘bake in’ the highest energy codes into its building standards from the …

Air transfer solution: ventilated doors

Australian Passive House designer Matt Purves posted online some intriguing photos of bespoke doors he built himself from leftover spruce wall panelling. These were for his home in Tasmania, which is targeting Passive House Plus certification. Ventilation systems need air to be able to move freely between rooms even when doors are closed. This is most often achieved by the …