Thornleigh Passivhaus

Spring is underway, but so is lockdown version 2.0. The flowers are out, but we are not. In September the split system was off for most of the month and the HRV slid in and out of 'heating season' and neutral modes of operation more times that I could keep track of. The HRV is working well and doing a great job of keeping the house in the comfort zone. During September we were all at home in our second significant COVID lockdown (and going a bit crazy). I continuing the graphic heavy format. Temperature from inside and outside the house as the percentage of hours in 0.5 °C bins. I've scaled the temperature in hopes that they will be comparable across months. 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 'hist'). Inside includes data from the wire...

[ In progress ] With the anniversary of moving in and sustainable house day coming up... I need to start running some numbers. I am also creating my annual index to posts so that I can find them when doing sustainable house day stuff! Power generation and usage... June 2021 old house and energy April 2021 energy musings (including battery) Water usage... Aug 2021 water update Dec 2020 HRV thoughts... Aug 2021 second guessing ERV Dec 2020 HRV in Sydney post Temperature & CO2... June 2021 Temperature analysis & plots June 2021 CO2 analysis & plots Air tightness July 2021 update

It has been a while since I've done a water update... Sydney Water: based on data from the last 8 water bills we have used 122kL over 646 days or an average of 189L/day. We have four people living here so individually we average 47 L/day. Comparing those numbers is a little tricky. Sydney Water data indicates that an average dwelling uses 623L/day . They also provide water efficiency targets by season , number of people and property size. For our property the comparison is > 900m² with 4 people. Sydney Water efficiency targets by quarter (L/day). Quarter Sydney Water Target TPH actual Aug - Oct 556 253 Nov - Jan 572 195 Feb - Apr 576 187 May - Jul 535 167 Despite by best intentions I have not yet put into place the software to measure the rain water tank usage directly, but I do have a system that measures the water height in the tank (Vegetronics) and a NetAtmo rain gauge.  The rainwater tank sensor reports full slightly below the actual full mark, so there...

Winter is done, but lockdown version 2.0 is not. In August 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 August we were all at home in our second significant COVID lockdown (and going a bit crazy). I am going to change to a more graphic heavy format. Temperature from inside and outside the house as the percentage of hours in 0.5 °C bins. I've scaled the temperature in hopes that they will be comparable across months. 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 ...

... 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 u...

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 ...