Thornleigh Passive House

I should preface this post by saying that I am not the kind of person who likes to wear a jumper in the house during the middle of summer or shorts inside the house during the middle of winter. I get that the Passive House standard is all about specific temperature (20 - 25 °C) and specific humidity levels (not measured as relative humidity), but to me 18 °C feels great when you walk in from 8 °C and 27 °C is blessedly cool when it is 40 °C outside. By which I mean to say that as a biologist I undertand that the we experience things relative to our frame of reference, but I also like data. So over the past 12 months we have had a few bits and pieces on loan from Zehnder and FanTech to see if ERV or HRV are better in the Sydney climate. I've learned alot in the process... and as I understand it none of this is commercial in confidence - quite to the contrary they are pleased for people to know about how their products work in Sydney. Spoiler: It works really well and I would abs...

The end of the calendar year is creeping up fast. The revised scripts are helping with the turnaround time. By way of a random COVID update... On average one adult is working from home five days a week and the other is at work, but the kids are in school. We set records for overnight temperatures on the last weekend of the month with our outdoor overnight temperature staying above 27 °C and the daily high on either side hitting 40 °C. While we normally turn off the A/C at 6pm every night (scheduled to align loosely with the end of solar generation) we left the A/C on overnight. Across the two days we ended up using ~ 1kW/day more than we generated do to higher A/C usage than normal, but the house temperature stayed a comparatively comfortable ~ 26 °C even when the outside temperatures were clearing 40 °C with no chance for openning the windows for nighttime ventilation to cool the house. Percentage of hours in below, within, above the 20 - 25 °C target temperatu...

Always easier when the first day of the month is on a Sunday! On it with the report this month. The revised scripts are helping with the turnaround time too. By way of a random COVID update... One adult is working from home 5 days a week and the other is at home about half the week, but the kids are in school. 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 1% 96% 2% outside 73% 17% 10% 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 12 wirelessTag sensors spread across every room of the house. Outside is the data from the wirelessTag sensors outside near the cubby house and HRV intake. The water wall and ...

Ooops... with all the various things going on I forgot to do the September summary. Slight change to the methodology this month (rather than calculating the hourly median for each sensor then taking the median of those I am directly calculating the median hourly temperature from all of the relevant sensors)... 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 7% 91% 2% outside 80% 15% 5% 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 12 wirelessTag sensors spread across every room of the house. Outside is the data from the wirelessTag sensors outside near the cubby house and HRV intake. The water wall, cleres...

You know it is bad when your architect says that the tables are not very good, but Andy was right - the graphs are way better than the tables. In looking at it I realised that I really needed to do it seasonanally (and monthly). This uses the same data as I have posted previously for sustainable house day... I am not sure why the plots look so bad here, but if you click on them the larger files look okay... (how about letting me use (svg?) Outside (green) and inside (blue) with 20 - 25 °C lines indicated. All of the x-axes (Temperature) span the same range, but the y-axis range (proportion of hours in 0.5 °C bins) varies.

... Currently a work in progress... Thermal Mass A material’s capacity to absorb, store and release heat. Thermal mass is typically used to moderate temperature extremes by releasing heat when the home is cool and absorbing heat when the home is warm. Specific heat capacity A material's capacity to store heat (measured per unit mass). Some materials are better at storing heat than others. Water can store 4× as much heat per kilogram as concrete. Density Mass per unit volume (mass / volume). Denser materials have more mass per volume so they can make up in density what they lack in specific heat capacity. Concrete has twice as much mass per m3 as water. Thermal conductivity The ease with which heat travels through a material. Ideally, thermal conductivity should be moderate so that the absorption and release of heat synchronises with the building's heating and cooling cycle. Both water and concrete are highly effective! In comparison, steel and water hold a similar a...

 This is mainly a way for me to put some numbers down so that I have them on Sunday for the Sustainable House Day panel... Sustainable House Day 2020 entry . Original solar blog post  (2020.Feb.29). Power and heating blog post  (2020.Aug.25). Latest water usage blog post  (2020.Jul.15). Night time ventilation blog post (2019.Oct.25). Carbon dioxide and HRV blog post (2019.Oct.01). Electrical Usage (from the Enlighten website, 204 days) Category Total Daily Produced 2.7 MWh 13.2 kWh Consumed 2.8 MWh 13.7 kWh Export 1.4 MWh 7.4 kWh Import 1.5 MWh 6.9 kWh Net Import 97 khW 475 Wh Because of the way the property is wired these numbers only include the house usage, excluding the garage / rainwater tank pump (which are minor). Percentage of hours in below, within, above the 20 - 25 °C target temperature range since 2019.Sep.22. Inside / Outside % < 20 °C % 20 - 25 °C % > 25 °C Inside 7% 85% 7% Outside...

 Our water wall got a photo in an article on passive houses in Issue 9.3 of Grand Designs Australia .

 We didn't win, but were "finalists" for the 2020  HIA Australian GreenSmart Custom Built award  and "highly commended finalists"for the 2020  HIA Australian GreenSmart Energy Efficiency award ! 

Another month of house data... The weather was down right cold although warming at the very end of the month. Two adults working from home except one who goes into the office for a couple of days. We have run the heater a fair bit to bring the house temperature up just a bit. We switched from the ERV to the HRV core during the month as our part of data collection on the two cores in the Sydney climate. 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 18% 82% 0% Outside 97% 2% 0% 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. Ou...

Today is the first anniversary of moving into our passive house... bittersweet to the data keen as we didn't have internet working well enough to log data effectively for another couple months (so we still don't have a year worth of data)... and solar installed for a few more months after that... and then not actually generating power for a few more. We still don't have the final occupancy certificiate, as we still have not yet fully realised the landscape plan (although the back yard grass was seeded three weeks ago and it has a noticeable green-ness to it). All in due time! Of course the National Broadband Network and solar did get installed and eventually even activated. The workbench in the garage and the bench seat in the front entry were built out of timber salvaged from the old house... and both are fit for purpose. We have made a lot of progress on the landscaping (a pallet plus of geohex was installed, lots of tons of wood chips and sandstone gravel have been place...

 Another event turns virtual... We pushed to unpack in time for sustainable house day in 2019, but the 2020 Sustainable House Day will be online . We've got a video in the can with the help of Andy Marlow and video editing expertise volunteered through Renew . Rumour on the street is that we will be participating in a Zoom session on "Passive House (Passiv Haus) Principles" from 17:00 – 17:45 (AEST) 20/09/2020 (Sustainable House Day).

Heating - how much do we use / need in our house? A simple question, but there are many ways to look at it. I've taken a fairly simplistic. I've used linear models to estimate the effect of temperature on energy usage. The graphical representation of the relation between temperature and energy usage is below...  Some key take aways for people not used to reading graphs: The vertical (y-axis) is daily energy consumption in kilowatts. The horizontal (x-axis) is temperature (in this case it is the running mean operating temperature [RMOT] recorded by the HRV). The dots are 160 individual days - each with a corresponding RMOT and energy consumption reading. The black line is straight and declining - indicating that energy use decreases as temperature increases. In fact for every degree colder we use an extra 0.5kW (this is the slope of the black line). The grey area encompasses 95% of the variation and there is considerable variation. Temperature explains ~ 39% of ...

Another month of house data... The weather was down right cold, with some decent rainfall towards the end of the month. Of course the big news this month was still COVID-19 (2 adults working from home except for a couple of days), but the kids were at school half the month due to the winter school holidays. We have run the heater a fair bit to bring the house temperature up just a bit. We were using the ERV core all month as our part of data collection on the two cores in the Sydney climate. 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 14% 86% 0% Outside 100% 0% 0% 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')...

We've recieved three water bills since moving in (how time flies)... for about half that time we have been working from home and even had the kids at home for six weeks. Even with all that we've done really well.  City water: the quarterly bill from the "old normal" was 172L/day, the lock down quarter was 198L/day, and the working from home quarter was 180L/day. So not too much variance really, and 183L/day over three quarters is good and puts us at 46L per person per day... about 20% of the typical Sydney resident.  Rain water: Since moving in we have been able to supply our laundry, toilet and garden needs for all but one week in January... without having to water some of the new plants we probably could have made it 100% on rain water for those needs. I plotted rain fall (from the NetAtmo rain gauge which is excellent) and water level in the rain water tank (using a Vegetronix AquaPlumb sensor, which the individual measurements (hou...

It took many more tries than I care to admit, but I finally managed to put the GoPro on the tripod to capture some timelapse photos capturing the performance of the fixed shading on the exterior of the house as well as the sunlight coming in through the water tanks across the day. 1. Outside - sun on the northern face of the house . 2. Inside sun on the translucent tubes .

Another month of house data... The weather is getting down right cold, with lots of modest rainfall. Of course the big news this month was still COVID-19 (2 adults working from home except for a couple of days towards the end of the month), but the kids were back to school all month. We have even run the heater a fair bit to bring the house temperature up just a bit. We were using the ERV core all month as our part of data collection on the two cores in the Sydney climate. 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 14% 85% 1% Outside 100% 0% 0% 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 includ...

Another month of house data... The weather is getting quite cool some nights, with enough rain for almost normal moisture back in the system. Of course the big news this month is still COVID-19 (2 adults working from home), but the kids were at school one day per week for a couple weeks before returning to school 5 days a week starting the 25th. The HRV target temperature is set to 23 °C and we even set the heating season to begin when the running mean outdoor temperature drops below 14 °C. We have even run the heater some to bring the house temperature up just a bit. We swapped the HRV core for the ERV core at the end of the month as our part of data collection on the two cores in the Sydney climate. 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 9% 91% 0% Outside 95% 5% 0% Methods: I have taken the 5 minutely data from the wirel...

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."

Our first quarterly water bill in the new house means water usage data! While water usage is not a "passive house" criterion, it is certainly related to the general principles of trying to live sustainably. From 14 October 2019 through 15 January 2020 we used 16,000L of water supplied from Sydney water (173L/day). While I don't have super precise numbers from the rainwater tank we probably used about the same about from the rainwater tank over the same period. Possibly the amount of rainwater used was a little bit more than that, but it could not have been much more. The reasoning behind estimating 16000 - 20000L from the rainwater tank... We had ~176mm of rain in mid-September which filled the tank (and then some), we had an additional ~22mm of rain the week before the water bill period started, so it would have been full at the start of the billing period (17500L capacity). On November 3rd we received 14mm of rain which would have topped it up a bit. In December w...

Data for the period during which we have occupied the house and had the sensors working (September 22 - December 31, 2019). Inside / Outside % < 20 °C % 20 - 25 °C % > 25 °C Inside 4 84 12 Outside 55 25 21 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 wirelessTag sensors spread across every room of the house as indicated below. Outside includes data from the wirelessTag sensors in the cubby house, outside, and HRV intake. Sensors from the water wall, clerestory, HRV-outlet and door data are not included in the summary. Temperatures from sensors deemed indicative of outside conditions... Outside sensor name Min 5% 25% Median 75% 95% Max CubbyHouse 5.9 11 16 19.4 24.3 33.3 44 HRV-Intake 9.6...

Another month in the house... Kind of. We were in residence 1 - 17 December while Andy Marlow (of Envirotecture fame) was in residence roughly from 20 - 31 December. So I only have first hand knowledge of the house for the first 17 days of the month. We have an interesting few days with no one in the house which I will examine separately. And I told Andy to enjoy living in the house and that he could do whatever air conditioning or anything else he wanted. Outdoor temperature ranged from 4 to 44 °C. Indoor temperature ranged from 17 to 31 °C. I used the A/C for a few hours to check the temperature sensor system I installed to check when the a/c was turned on, and based on the data it looks like Andy used the A/C for a few hours on a particularly hot day, but I have not checked the temperature logs in detail. Inside / Outside % < 20 °C % 20 - 25 °C % > 25 °C Inside 3.4 84.2 12.5 Outside 55.0 24.7 20.7 Methods: I have taken the 5 minutely data from the wireles...