Thornleigh Passivhaus

The first quarterly bill for the house with solar fully working... As a reminder we have a solar panel system, but no battery system. On average we used 6.9kWh/day from the grid and returned 7.1 kWh/day to the grid. Between connection fees, electricity costs and rebates our electricity costs were ~ $2/day... for about half of that period all four of us were at home... every... day. While there is a real appeal to a battery system, it will be very hard to make an economic case for one when the potential savings is ~ $1.40 per day. At least until the cost for a ~7kW battery system comes down to ~$5114 (assuming a 10 year payback).

Another month of house data... The weather was mostly nice, with enough rain for almost normal moisture back in the system and enough cloud to reduce our solar generation. Of course the big news this month is still COVID-19 (2 adults + 2 children) at home... all... of... the... time... and we are not too crazy yet. As the season has changed I have moved the HRV target temperature up higher to 21 °C and then to 23 °C at the very end of the month. The need for nighttime cooling appears to be behind us, and we would have hit 100% of hours in the target range except for not quite managing the changing of target temperatures in changing weather. 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 0% 98% 2% Outside 74% 22% 4% Methods: I have taken the 5 minutely data from the wirelessTag sensors and calculated the median temperature of each ...

Another month of house data... The weather is getting nice, with enough rain to put almost normal moisture back in the system. Grass is actually growing! Of course the bug news this month is COVID-19, so starting the 24th we have had everyone (2 adults + 2 children) at home... all... of... the... time... and we are not too crazy yet. Power usage data is included in the monthly summary for the first time. We were net energy producers for the month (63.4kWh net production, or 2.3kWh/day). Because we don't have batteries, we exported 226kWh and imported 162kWh. Inside / Outside % < 20 °C % 20 - 25 °C % > 25 °C Inside 7 92 1 Outside 62 30 9 Methods: I have taken the 5 minutely data from the wirelessTag sensors and calculated the median temperature of each sensor 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 12 wi...

Another month of house data... Temperatures were much nicer in February than in January, with some welcome rain to put some moisture back in the system. The A/C was rarely this month, mainly when night time temperatures didn't drop or when the day time temperatures climbed into the mid-40's... still haven't written the A/C script. For the record: 28 °C inside feels really good when it is 43 °C. The cubby house sensor got wet during the big storm and is no longer reporting data. Inside / Outside % < 20 °C % 20 - 25 °C % > 25 °C Inside 3 83 14 Outside 37 44 19 Methods: I have taken the 5 minutely data from the wirelessTag sensors and calculated the median temperature of each sensor 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 12 wirelessTag sensors spread across every room of the house. Outside is th...

As of February the solar is finally installed and working as it should have been back in August. It was a major drama to get the solar panels installed due to the SIP roofing. Apparently most solar installs involve driving bolts through the roof into the building frame... But we don't have a building frame, the SIP is our air tight layer, not to mention we don't want a bunch of thermal bridges. It took contracts with two different companies (not being a standard install was too much for most companies contacted about the installation), and eventually it took two install attempts by the second company when the first bracket they tried did not fit as required. The very big tree that shades our roof made it a bit hard to predict the generation capacity, but our 5.22kW system is generating power that would be expected from an unshaded ~ 4kW system (~ 17kWh / day). Which more than offsets our typical consumption ~ 7kWh / day. Once we have enough data I'll post a more detailed ...

Another month of house data... Averaged hourly outdoor temperature ranged from 15 to 46 °C. Averaged hourly indoor temperature ranged from 19 to 30 °C. We used the A/C a fair bit this month, mainly when night time temperatures didn't drop or when the day time temperatures climbed into the mid-40's. I have a temperature sensor which is deployed so that I can identify the hours during which the A/C is on...but I have not yet written that R script (something else on my extensive to do list). The default setting for the AC is 23 °C. The summary data for sensors nearest the A/C indicate those areas were above the 25 °C only 18% of the hours of the month where the other sensors were over 25 °C 36% of the hours. That suggests that we ran the A/C about half of the hot days. We had some really hot day this month, and some exceptionally hot nights too. Inside / Outside % < 20 °C % 20 - 25 °C % > 25 °C Inside 0 66 34 Outside 24 42 32 Methods: I have taken th...

The opening screen grab should look familiar to readers here... ABC 7.30 Passive homes helping to cut energy bills is 5 minutes of good public relations for passive houses in Australia. Thornleigh Passive House gets more visual presence in the story than the transcript would indicate, but my favourite bits from the transcript are: JASON OM: "This house in Sydney,... , is no ordinary home. It's called a passive house where energy efficiency is taken to extremes." OLIVER STEELE: "I think the Australian industry has a long way to go before passive house becomes the norm but hopefully projects like this one and the houses that are getting some attention will encourage people to start demanding this from the industry."