Heating

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GUEST OBSERVATION
Australians need better solutions for coping with the warmer climate of the future (and present). 
Australian houses use <a href="http://www.lowcarbonlivingcrc.com.au/resources/crc-publications/crclcl-project-reports/rp1017e-validating-and-improving-basix-energy" target="_blank">significantly more electricity</a> to stay warm or cool than estimated during the design stage.
To design a new house in Australia, the building needs to meet the national construction code. One way to do this is by using software to simulate the building’s thermal efficiency, to see if it meets the minimum requirements of the national house energy scheme. The scheme divides Australia geographically into 69 different climate zones and requires new houses to be thermally appropriate for their environment.
Unfortunately, this software does not properly take into account our warming weather. Our <a href="http://www.lowcarbonlivingcrc.com.au/resources/crc-publications/rp1041-improving-thermal-performance-dwellings-carbon-positive-and" target="_blank">recent report</a> found the climate assumptions used by the government drastically underestimate the length and heat of summers in the near future.
In fact, buildings that perform best for heat waves predicted by 2030 are actually banned by the government’s building code. We urgently need to update our building codes to cope with our changing climate.
Understand the future local climate
We took Richmond in New South Wales as an example to understand the effect a changing climate might have on building performance. By taking predictions from <a href="http://www.exemplary.com.au/download/CSIRO%20Future%20climate%20data%20100%20solar%20sites%20-%20Exemplary%20-%20Final.pdf" target="_blank">CSIRO’s medium greenhouse gas emissions scenario</a>, we analysed Richmond’s likely weather for every week of 2030.
The future outlook, shown below, is strikingly different from the <a href="http://www.nathers.gov.au/nathers-accredited-software/nathers-climate-zones-and-weather-files" target="_blank">weather files</a> used to determine whether houses meet the minimum thermal performance requirement of the National Construction Code. In 2030, Richmond will experience a warm period almost four times longer than predicted by the official weather file.
<a href="https://images.theconversation.com/files/283169/original/file-20190708-51312-1i18f0d.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img src="https://images.theconversation.com/files/283169/original/file-20190708-51312-1i18f0d.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" alt=""></a>
Author provided
Design for the future
Based on the future climate scenario, the design strategy for buildings in Richmond should focus on well shaded and insulated buildings to avoid any heat gain in the warm period, but should also harness sunlight to warm up the indoors in the cool period.
The warm period will last from December to March, when keeping the house cool is the priority. Passive solar heating, such as northern windows and well-insulated walls, floor and ceilings, are important during the May to September cool months, while direct ventilation is largely all that’s needed during the mostly comfortable April and October to November.
To test how houses will perform in a hotter future, we modelled a house in Richmond using AccuRate software. We found a design and construction solution that performed well (achieving 7.6 stars out of 10) for the 2030 scenario failed to meet a <a href="https://www.basix.nsw.gov.au/iframe/images/BASIX_Thermal_Comfort_Protocol_July17_rev1_Nov2017.pdf" target="_blank">heating threshold</a> that is legally required in NSW. In effect, the house that makes the most sense for the immediate future, could not be built.
These thresholds for heating and cooling are based on assumptions that are out of step with current conditions, let alone the future. Between 2016 and 2018 Richmond’s annual average temperature was 17.8℃, whereas the <a href="http://www.lowcarbonlivingcrc.com.au/resources/crc-publications/rp1041-improving-thermal-performance-dwellings-carbon-positive-and" target="_blank">NatHERS weather file</a> assumes it to be 16.7℃. This difference is set to increase.
In a 2019 amendment, the National Construction Code adopted NSW’s approach to heating and cooling thresholds to <a href="https://www.abcb.gov.au/Resources/Publications/Education-Training/NatHERS-heating-and-cooling-load-limits" target="_blank">other climate zones</a> in other states. The heating threshold puts a restraint on designing buildings that are optimised to mitigate extreme heat events.
This highlights the limitation of out-of-date climate files, and the current regulation that acts as a barrier to developing energy efficient designs for a future warmer climate.
Build to perform
A 2013 <a href="https://www.energy.gov.au/publications/evaluation-5-star-energy-efficiency-standard-residential-buildings" target="_blank">CSIRO study</a> found that houses with higher star ratings using more energy in summer.
One of the reasons is the trade-offs on the thermal performance of one building component against another in the Nationwide House Energy Rating Scheme (NatHERS) software. For example, a window without shading on the western façade is acceptable in a NatHERS simulation, whereas the same window would not be allowed if a <a href="https://www.abcb.gov.au/Resources/Tools-Calculators/Glazing-Calculator-NCC-2014-Volume-Two" target="_blank">glazing calculator</a> developed by the National Construction Code were used to demonstrate the thermal performance of a house.
Other issues are trade workmanship, such whether a building is airtight. Airtightness in residential buildings is ignored in the national construction code. However, considerable energy savings can be achieved if a house can be made airtight.
<a href="https://images.theconversation.com/files/283170/original/file-20190708-51262-8pfb7c.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img src="https://images.theconversation.com/files/283170/original/file-20190708-51262-8pfb7c.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" alt=""></a>
 (Author provided)
Similarly, missing or displaced insulation in the ceiling, as shown above, can cause significant discomfort and additional heating and cooling costs. We all, from builders to homeowners, need to understand insulation must be carefully installed and cannot be moved later, or even well designed buildings will become inefficient.
Windows are the main option for ventilating most houses. However, if you live in a high-pollution or noisy area, or in a place with very little wind, open windows might not be desirable or practical. Consequently, households may not be getting enough fresh air to maintain a healthy indoor environment. A mechanical ventilation system, which uses little energy, is an ideal alternative.
The current weather files and heating thresholds used to develop minimum building standards are inadequate for our warming climate. Our report presents a framework for designing and building houses that consider climate change. We hope to see further research on other Australian population centres, so we can develop a comprehensive overview to help us build energy efficient and healthy houses for the future.<img src="https://counter.theconversation.com/content/120072/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important; text-shadow: none !important;">
Anir Kumar Upadhyay, Lecturer in Built Environment, UNSW
Chris Lockhart Smith, Director - ecodweller, UNSW
Krishna Munsami, PhD student, UNSW
This article is republished from <a href="http://theconversation.com" target="_blank">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/houses-for-a-warmer-future-are-currently-restricted-by-australias-building-code-120072" target="_blank">original article</a>.
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j.ballantyne1990-6AQqhLzZaK

Houses for a warmer future are currently restricted by Australia's building code

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GUEST OBSERVATION
Cold weather has arrived in eastern Australia, to the glee of those who enjoy skiing. But you don’t have to venture onto the slopes for cold to be a danger. With gas prices rising, many in the community are shivering while contemplating how big their next gas bill will be.
Eastern Australia’s gas market is rapidly changing, driven by the first exports of liquefied natural gas (LNG) from Queensland. And this is affecting the whole supply chain, from gas producers, to the way we use gas in our homes.
Gas was cheap, for decades
In Victoria, South Australia, and through to New South Wales, Queensland and Tasmania, gas has long been viewed as the preferred fuel for many applications - from industrial uses right down to warming our lounge rooms. Since the discovery of the massive Bass Strait oil and gas deposits off Victoria in the late 1960s, gas consumption across eastern Australia grew, decade after decade.
But despite these discoveries and growing production, the resource companies involved were often frustrated. While global crude oil prices went up and up, eastern Australian gas prices were stuck in the 1970s. Gas consumers enjoyed access to some of the cheapest gas in the developed world.
On the other hand, gas producers dared not complain too loudly. They often considered this gas nearly a waste product – interfering as it did with the speed at which the far more valuable crude oil and LPG could be drawn from the ground. If eastern Australia had been another jurisdiction such as Nigeria or North Dakota, this nuisance gas could have been quickly disposed of by flaring or venting. However, with some foresight, Australian industry regulators have generally discouraged such wasteful and environmentally damaging practices.
Faced with this constraint, what were the resource companies to do? Unlike crude oil, gas is costly to ship to the more lucrative markets in Japan and Korea, first requiring liquefaction at temperatures as low as minus 160C. Creating new demand “sinks” for gas in-country was one strategy. Pipelines were built to connect up all of the eastern states. Still, this “domestic” gas languished at a sales price far below that of crude oil.
Coal seam gas arrives
Then in the first decade of this century came the realisation that coal seam gas (CSG), located mostly in Queensland but also in New South Wales, could be produced in quantities far exceeding the demands of the staid domestic market, by a factor of three or more.
Following the examples of Western Australia and the Northern Territory, the only option for gas companies was to invest billions of dollars in, at last, building the first liquefaction and export facilities on Australia’s east coast.
For legacy gas producers, even those not directly involved in the LNG-export decisions, this was the dream come true. After decades, a buyers’ market rapidly shifted to become a sellers’ market. Where previously buyers would remind producers they would be happy to take that “waste product” off their hands, producers could now inject into supply contract negotiations the spectres of “world-parity pricing” and “high CSG production costs”.
Nowhere in the world had it ever occurred where an established, reasonably large domestic market, serving customers ranging from large industry to millions of homeowners, was suddenly eclipsed by the mammoth export-focused LNG industry.
Eastern Australia gas demand peaked - three years ago
Even before the launch of the first LNG export cargo from Queensland late last year, major gas buyers raised concerns about future gas costs and contractual availability. The Australian Competition and Consumer Commission is examining transparency and barriers to competition in the gas industry.
When the New South Wales upper house held an inquiry into gas supplies earlier this year, it gave us, at the University of Melbourne Energy Institute, the opportunity to present our analysis of declining future gas demand in that state. Now Victoria’s upper house is likewise having an inquiry where we will present aspects of our extended research into gas supply and demand across all of eastern Australia.
The eastern Australian gas market has experienced significant upheaval and will continue to change over the next ten years. Data from the Australian Energy Market Operator indicates that the volume of gas used in eastern Australia peaked three years ago.
Gas demand will continue to decline across all sectors. In the electricity-generation sector, with rising gas prices, the abolition of the carbon price, and a surplus of coal-fired generation, gas will only be sparingly used. The Australian Energy Market Operator is also forecasting a steep drop in the amount of gas used by industry.
Do try this at home: fuel-switching from gas to electricity
The amount of gas used in buildings will also decline. As we shiver here in Melbourne, how would you like to reduce your heating costs by up to, say, 70%? If interested, you have to do two things: (1) turn your gas heater to “off” and (2) turn your reverse cycle air conditioner to “on” – on heating mode of course!
<a href="/images/2015/07/20/image-20150717-5067-1y3854o.jpeg" target="_blank">Click to enlarge</a>
<img src="/images/2015/07/20/image-20150717-5067-1y3854o.jpeg" alt=""> 
 
In my home we did that for the first time this winter. Our savings are remarkable, though not surprising nor different to what others in the community are reporting. As an example, during two particularly blustery days I found I could comfortably heat my house one day with gas at an energy-only cost of A$4.80 and then do it the next day with my air conditioner at a cost of just A$1.50. Our savings across the full heating season will add up to hundreds of dollars.
Results in other homes will depend on factors including what you pay for electricity and gas, the efficiencies of your gas heater and air conditioner, where your heat sources are located within your home, and individual comfort and convenience preferences. But it should not be long before word gets out to the 4.4 million Australian homes that already have at least one reverse-cycle air conditioner.
Previously I reported on the similarly large savings possible by using an efficient heat pump to heat water, especially if you have excess self-generated solar electricity. Add an induction cooktop and there is no economic need to connect gas to most Australian homes<a href="https://www.ata.org.au/news/are-we-still-cooking-with-gas">.</a> Businesses are springing up that offer “all-electric” home conversions” to people interested in making the switch.
Collectively, homes are large consumers of eastern Australian gas. This coming “second-era of Australian home electrification” will have a big impact on gas and electricity supply-demand dynamics over the next decade.
Tim Forcey is energy advisor for the Melbourne Energy Institute and also an author for The Conversation. He can be contacted <a href="https://theconversation.com/profiles/tim-forcey-104740" target="_blank">here</a>.
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