Thornleigh Passive House

... Two years! Wow, the time flies! I've picked up some new wireless tag sensors that can plug in to a USB wall plug and will use fewer button batteries. I am still working to get all those placed, but I've got one in the uninsulated detached garage and one in the study again. I am probably overdue to explain the gradual changes to the monitoring system, but that is not this post. I did a day of calibration (August 11th) where I pulled all the sensors and put them in one place so that I could make sure that they all had the same sense of temperature and humidity. They were all fairly close, but I tweaked individual sensor calibrations by up to ~0.3 °C for some sensors. The Netatmo CO₂ sensors were fairly far out since they recalibrate to 400ppm based on the assumption that CO₂ levels drop to 400ppm at least once a week. Normally that would not be an issue, but lockdown. Yes, one of the lesser appreciated impacts from the lockdown is that my CO₂ sensors were underestimatin

I've been a bit busy lately, so I've not had a chance to run the formal numbers... and there are a lot of variables at play, but... My partner and I have noticed that the house is a lot drier this winter than it was last winter when we were alternating the HRV and ERV cores. A glance at the data suggests that the ERV does what it is supposed to do and helps keep moisture in the house during the winter heating period. I am planning to have a look at the moisture levels in the house between the ERV and HRV periods. I've attached a summary plot from the our system which does hit at what I am talking about... Compare the May / June period from 2020 and 2021. Just peeking at the graph it looks like the ERV maintains a much higher humidity (but still in the good range) than the HRV core with supply values ~ 10g/Kg for the ERV core versus 6-7g/Kg for the HRV core. In the most comparable time last year we were not at home 100% of the time like we have been this year. So maybe a hu

Winter is here, and so is lockdown version 2.0. In July the split system ran as a heater for most of the month from ~9:45am until 3:30pm, scheduled to take advantage of the solar production during that part of the day. On cooler nights we kept it on set to 19 °C. The HRV is working well and doing a great job of keeping the house in the comfort zone, although the gound floor is consistently a few degrees cooler than the top floor. During July we were all at home in our second significant COVID lockdown (and going a bit crazy). Percentage of hours in below, within, above the 20 - 25 °C target temperature range for the month. Inside / Outside % < 20 °C % 20 - 25 °C % > 25 °C inside 39% 61% 0% outside 99% 1% 0% Methods: I have taken the 5 minutely data from the wirelessTag sensors and calculated the median temperature for each hour and determined the proportion of hours falling inside of the 20 - 25 °C target temperature (using the R functions 'aggregate' and