Build better houses to solve dry year energy problem

Newsflash: using less energy is better than generating more of it. I know that seems obvious given the cost of new electricity generation schemes but it’s even more significantly beneficial to reduce peak heating demand because of New Zealand’s big dry winter problem. The University of Otago’s energy programme is producing valuable work, and its latest paper by Michael Jack …

Revised ASHRAE standard gets serious on building decarbonisation

ASHRAE in the USA is really focusing on building decarbonisation, finally. ASHRAE Journal March 2024 contains a really readable summary of the changes to ASHRAE Standard 100-2024, Energy and Emissions Building Performance Standard for Existing Buildings. This amounts to a deep retrofit of the standard, which now will address both energy emissions (via Energy Use Intensity, EUI) and carbon emissions …

10 Passive House design tips for keeping cool in summer

The high temperatures this past summer have served to sharpen everyone’s focus on how to design Passive House buildings to remain comfortable for longer when the temps spike. The team at Sustainable Engineering Ltd is working on detailed energy modelling in order to produce building specification guidelines. We’ve also been thinking about what could be implemented right away: finding the …

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 …