Airtightness, explained (plus, see blower doors in action)

Check out these helpful instructional videos on airtightness and air leakage testing. Made in Australia, the general observations about lack of awareness of the importance of airtightness apply here too. This series of three short videos (less than seven minutes each) is produced by Efficiency Matrix, a supplier of products and testings for airtightness. The first video is absolutely worth …

Need more than just higher performance building code changes to decarbonize

“In buildings, it has become clear that there are two very distinct problems. One concerns new buildings — where, for example, advanced heat pump technology can allow for electrification of heating systems. The other, much bigger problem is how to cut emissions from existing buildings, which will account for most emissions from this sector. Here the actions are a blend …

Mouldy Schools Resource

Mouldy Schools Resource Some advice from health professionals and articles on damp mouldy schools. We are building scientists and are not health professionals or even public health researchers (we strongly recommend listening to those folks and enjoy learning at Public Health Summer School each year in Wellington). Advice for homes which is applicable to schools as well. Schools for Health show …

Yes – it’s a Passive House Plus Office Building

Crazy looking building: but under the iridescent facade is a standard form office building. Well, standard aside from the funky double concrete staircase. The architect’s website has some great photos. but the really interesting point is the performance … this is a Certified Passive House Plus. It’s listed as the largest certified project in France as at the time of …

New NZ homes emitting 5x more carbon than <2 deg budget allows

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 …