Is the rental property or properties you own or manage capable of killing your tenants?

 

Are you on the board of a not-for-profit organisation that provides social or affordable rental housing? Do you have a residential property portfolio or do you just own a second home your rent out?

Then this post is written for you to consider.

Is the rental property or properties you own or manage capable of killing your tenants?

ACOSS Heat Study 2024, 1 March 2024, excerpt:

Hotter days and homes with poor energy performance create hot boxes that cannot be cooled

People variously described living in hot homes that they cannot cool as “awful”, “unliveable”, “miserable”, “unbearable”, “torture” and “a prison.”

Of the 1007 people who completed the survey, most (80.4%) said their home gets too hot in the summer.

Over half the people surveyed (56.7%) said they struggle to cool their home.

At a state and Territory level, more than half of people in Western Australia (67.2%), Queensland (66.1%), Australian Capital Territory (64.3%) and New South Wales (55.0%) said their home gets too hot and they struggle to cool it. Nearly half of the people surveyed in Victoria (45.8%), South Australia (45.7%) and the Northern Territory (45.5%) also had this experience. Tasmania was the only jurisdiction where all people surveyed said either their home was comfortable, or they are able to cool it when hot.

Some groups were more likely to struggle to cool their home:

• people renting in social housing (78.3%)

• people receiving income support (60.8%)

• people renting directly from a real estate agency (68.6%) or landlord (56.7%).

People in social or private rental properties have very limited control to make changes to their home to make it more energy efficient and resistant to extreme temperatures. They have limited control to install insulation, draft proofing, shading, fans or air conditioners, regardless of whether or not they can afford these changes. Of the 558 people living in social housing or private rental, most (69.7%) said they struggle to cool their home. [my yellow highlighting]

“I rent and there is no air con. Though I have fans, that can’t compete with high temps.

My apartment is north-west facing at top of the block.”

- Judith, New South Wales

People who indicated that they were in insecure housing (3%) also spoke of having limited control to cool their home when it gets too hot.

Healthy Futures, media release, 26 March 2024, excerpt:

Heat-related illnesses kill thousands of Australians every year (1) and roughly one-third of these deaths can be attributed to climate change (2,3). Heatwaves increase the risk of dehydration, kidney failure, heart attacks and strokes. Older people, children, people with pre-existing health conditions and people unable to afford air conditioning are most vulnerable. [my yellow highlighting]

Currently, many social housing dwellings are poor quality and prone to temperature extremes (4-6). A 2023 survey of people on low incomes by the Australian Council of Social Services found that 94.5% avoided using air conditioning because it is too expensive (7). Solar panels can significantly reduce air conditioning costs, and while 30% of Australian homes now have rooftop solar, rooftop solar coverage on social housing in New South Wales, for example, is only 7% (8).

Energy efficiency retrofits and renewable-powered air conditioning will not only protect people from extreme temperatures and drive down costs of living; they will also mitigate climate change and its health impacts in the long term by reducing dependence on polluting fossil fuel-based electricity.

Nature Climate Change, 11, pages 492–500 (2021)

Published 31 May 2021:

The burden of heat-related mortality attributable to recent human-induced climate change

A. M. Vicedo-Cabrera, N. Scovronick, F. Sera, D. Royé, R. Schneider, A. Tobias, C. Astrom, Y. Guo, Y. Honda, D. M. Hondula, R. Abrutzky, S. Tong, M. de Sousa Zanotti Stagliorio Coelho, P. H. Nascimento Saldiva, E. Lavigne, P. Matus Correa, N. Valdes Ortega, H. Kan, S. Osorio, J. Kyselý, A. Urban, H. Orru, E. Indermitte, J. J. K. Jaakkola, N. Ryti, M. Pascal, A. Schneider, K. Katsouyanni, E. Samoli, F. Mayvaneh, A. Entezari, P. Goodman, A. Zeka, P. Michelozzi, F. de’Donato, M. Hashizume, B. Alahmad, M. Hurtado Diaz, C. De La Cruz Valencia, A. Overcenco, D. Houthuijs, C. Ameling, S. Rao, F. Di Ruscio, G. Carrasco-Escobar, X. Seposo, S. Silva, J. Madureira, I. H. Holobaca, S. Fratianni, F. Acquaotta, H. Kim, W. Lee, C. Iniguez, B. Forsberg, M. S. Ragettli, Y. L. L. Guo, B. Y. Chen, S. Li, B. Armstrong, A. Aleman, A. Zanobetti, J. Schwartz, T. N. Dang, D. V. Dung, N. Gillett, A. Haines, M. Mengel, V. Huber & A. Gasparrini

Abstract

Climate change affects human health; however, there have been no large-scale, systematic efforts to quantify the heat-related human health impacts that have already occurred due to climate change. Here, we use empirical data from 732 locations in 43 countries to estimate the mortality burdens associated with the additional heat exposure that has resulted from recent human-induced warming, during the period 1991–2018. Across all study countries, we find that 37.0% (range 20.5–76.3%) of warm-season heat-related deaths can be attributed to anthropogenic climate change and that increased mortality is evident on every continent. Burdens varied geographically but were of the order of dozens to hundreds of deaths per year in many locations. Our findings support the urgent need for more ambitious mitigation and adaptation strategies to minimize the public health impacts of climate change. [my yellow highlighting]

The Lancet, Planetary Health, Volume 5, Issue 7, E415-E425

Article published July 2021, excerpts:

Global, regional, and national burden of mortality associated with non-optimal ambient temperatures from 2000 to 2019: a three-stage modelling study

Prof Qi Zhao, PhD Prof Yuming Guo, PhD Tingting Ye, MSc Prof Antonio Gasparrini, PhD Prof Shilu Tong, PhD Ala Overcenco, PhD Aleš Urban, PhD Alexandra Schneider, PhD Alireza Entezari, PhD Ana Maria Vicedo-Cabrera, PhD Antonella Zanobetti, PhD Antonis Analitis, PhD Ariana Zeka, PhD Aurelio Tobias, PhD Baltazar Nunes, PhD Barrak Alahmad, MPH Prof Ben Armstrong, PhD Prof Bertil Forsberg, PhD Shih-Chun Pan, PhD Carmen Íñiguez, PhD Caroline Ameling, BS César De la Cruz Valencia, MSc Christofer Åström, PhD Danny Houthuijs, MSc Do Van Dung, PhD Dominic Royé, PhD Ene Indermitte, PhD Prof Eric Lavigne, PhD Fatemeh Mayvaneh, PhD Fiorella Acquaotta, PhD Francesca de'Donato, PhD Francesco Di Ruscio, PhD Francesco Sera, MSc Gabriel Carrasco-Escobar, MSc Prof Haidong Kan, PhD Hans Orru, PhD Prof Ho Kim, PhD Iulian-Horia Holobaca, PhD Jan Kyselý, PhD Joana Madureira, PhD Prof Joel Schwartz, PhD Prof Jouni J K Jaakkola, PhD Prof Klea Katsouyanni, PhD Prof Magali Hurtado Diaz, PhD Martina S Ragettli, PhD Prof Masahiro Hashizume, PhD Mathilde Pascal, PhD Micheline de Sousa Zanotti Stagliorio Coélho, PhD Nicolás Valdés Ortega, MSc Niilo Ryti, PhD Noah Scovronick, PhD Paola Michelozzi, MSc Patricia Matus Correa, MSc Prof Patrick Goodman, PhD Prof Paulo Hilario Nascimento Saldiva, PhD Rosana Abrutzky, MSc Samuel Osorio, MSc Shilpa Rao, PhD Simona Fratianni, PhD Tran Ngoc Dang, PhD Valentina Colistro, MSc Veronika Huber, PhD Whanhee Lee, PhD Xerxes Seposo, PhD Prof Yasushi Honda, PhD Prof Yue Leon Guo, PhD Prof Michelle L Bell, PhD Shanshan Li, PhD

Introduction

Earth's average surface temperature has risen at a rate of 0·07°C per decade since 1880, a rate that has nearly tripled since the 1990s.1 The acceleration of global warming has resulted in 19 of the 20 hottest years occurring after 2000 and an unprecedented frequency, intensity, and duration of extreme temperature events, such as heatwaves, worldwide. Exposure to non-optimal temperatures has been associated with a range of adverse health outcomes (eg, excess mortality and morbidity from various causes).2, 3, 4, 5, 6 All populations over the world are under certain threats from non-optimal temperatures, regardless of their ethnicity, location, sex, age, and socioeconomic status. For example, in China, 14·3% of non-accidental mortality in 2013–15 might have been related to non-optimal temperatures, with 11·6% of deaths explainable by cold exposure and 2·7% explainable by heat exposure.7 In the USA, the risk of mortality increased by 5–12% due to cold exposure and 5–10% due to heat exposure between 2000 and 2006.8 An association between ambient temperature and mortality risk has also been reported in India, Australia, the EU, South Africa, and other countries and regions. 9, 10, 11  [my yellow highlighting]

Figure 1 Average daily mean temperatures of the 750 locations from the 43 countries or territories included in the analysis

The colours represent the different ranges of average daily mean temperature during the data collection periods shown in the appendix (p 4).

Daily minimum and maximum temperatures between Jan 1, 2000, and Dec 31, 2019, were collected from the Global Daily Temperature dataset (grid size 0·5° × 0·5°) of the Climate Prediction Center. This dataset was developed, by use of a Shepard algorithm with observational data from 6000 to 7000 weather monitoring stations worldwide,15 as a benchmark for a range of reanalysis products and climate change models. Daily mean temperature was calculated by averaging daily minimum and maximum temperatures.

ScienceDirect

Energy and Buildings

Volume 272, 1 October 2022:

Integrated assessment of the extreme climatic conditions, thermal performance, vulnerability, and well-being in low-income housing in the subtropical climate of Australia

Shamila Haddad, Riccardo Paolini, Afroditi Synnefa, Lilian De Torres, Deo Prasad, Mattheos Santamouris

Abstract

Social housing stock worldwide can be characterised by poor indoor environmental quality and building thermal performance, which along with the increasing urban overheating put the low-income population at higher health risk. The dwellings’ thermal performance and the indoor environmental quality are often overlooked in the context of social housing compared to the general building stock in Australia. In the present study, the synergies between urban microclimate, indoor air temperature, housing characteristics and quality of life of residents have been investigated by employing subjective and objective assessment of indoor environmental quality in 106 low-income dwellings during the winter and summer of 2018–2019 in New South Wales. It further examines the impact of urban overheating and levels of income on indoor thermal conditions. The subjective method involved assessing the links between the type of housing in which low-income people live, energy bills, self-reported thermal sensation, health and well-being, and occupants’ behaviours. The results show that many dwellings operated outside the health and safety temperature limits for substantial periods. Indoor air temperatures reached 39.8 °C and the minimum temperature was about 5 °C. While the upper acceptability limit for indoor air temperature was 25.6 °C for 80 % satisfaction, periods of up to about 997 and 114 continuous hours above 26 °C and 32 °C were found in overheated buildings, respectively. Indoor overheating hours above 32 °C were recorded up to 238 % higher in Sydney’s western areas compared to eastern and inner suburbs. Similarly, residents in westerns suburbs and regions experience more outdoor overheating hours than those living near the eastern suburbs. This study highlights the interrelationships between ambient temperature, housing design, income, thermal comfort, energy use, and health and well-being in the context of social housing. The evidence of winter underheating and summer overheating suggests that improvements in building quality and urban heat mitigation are required to minimise the impacts of poor-performing housing and local climate. [my yellow highlighting]

That Australia faces rising air, land & sea surface temperatures is a situation that can no longer be denied and yet federal, state and local governments are not fully addressing the thermal mass of subdivision & individual residential dwelling design

 

The fact that ambient air temperature, lad surface and sea surface temperatures are rising across the Australian continent can no longer be denied.

GRAPH: Australian Bureau of Meteorology

In New South Wales generally average maximum temperatures in the month of January 2024 ranged from around 24°C to 36-39°C, spiked by days on end of heatwave temperatures which often broke temperature records for individual localities.

MAPPING:  Australian Bureau of Meteorology

In the north-east coastal zone of the state the minimum air temperature was 1°C higher and maximum air temperature 1-2°C higher than they were between 1981-2010.

In January the highest Northern Rivers region minimum & maximum recorded daily temperature range was:

Evans Head 24.8—38°C

Grafton 24.5—37.6°C

Yamba 25.6—37.2°C

Murwillumbah 27.1—36.2°C

Casino 27.1—36.2°C

Lismore 24.5—35.6°C

Tabulam 23.0—34.9°C

Byron Bay 25.6—32.7°C

Ballina 24.9—34.2°C

Note: These are the nine official Bureau of Meteorology weather stations in the Northern Rivers region.

Yet despite all this new subdivision schemes and housing designs are paying little more than lip service to sustainability and mitigating the thermal load of both the internal road networks of these subdivisions or the collective & individual loads of dwelling contained there in.

Apparently, multi-dwelling structures that increasing look like a collection of boxes are skating through BASIX requirements on the presumption that each individual box within these boxes will be fully air conditioned at some point before occupation or that if ceiling fans are fitted to some of the rooms then this will mitigate heat.

An assumption which:

(i) takes no account of the increasing stress air conditioning places on a household's cost of living. Because the price per kilowatt hour & associated charges of residential electricity supply continues to rise and commonly these multiple dwelling boxes are not built with any rooftop solar power grid to mitigate cost;

(ii) completely ignores the increasing risk of destructive storms causing levels of damage to power supply infrastructure that cuts power supply to both collections of streets or entire towns for days/weeks at a time. As occurred in heatwave conditions in 2024; and

(iii) appears to leave the thermal load of closely clustered internal roads out of the equation completely.

I expect the latest collection of boxes being considered by Clarence Valley Council will also get the nod because I have yet to see this local government apply the full suite of climate change policies to every development application before deciding consent. The heat footprint of an application rarely rates a mention in Council-in-the-Chamber debates or elicits questions to senior staff attending. Neither are there many mentions of the heat island affect caused by new roads, pavements and driveways. Nor does the wind resistance factor of a proposed building arise - and given the entire Clarence Coast is now in a cyclone risk zone that borders on the negligent when assessing new development applications.

Artists impression of street view of 6 Yamba Road, Yamba proposed subdivision. IMAGE: BDA

Set out below are some basic facts about how the freestanding houses, town houses, duplexes, units and flats we live in attract and retain heat.

Australian Government, Your Home, retrieved 19 February 2024:

Passive Design

What is thermal mass?

In simple terms, thermal mass is the ability of a material to absorb, store and release heat. Materials such as concrete, bricks and tiles absorb and store heat. They are therefore said to have high thermal mass. Materials such as timber and cloth do not absorb and store heat and are said to have low thermal mass.

In considering thermal mass, you will also need to consider thermal lag. Thermal lag is the rate at which heat is absorbed and released by a material. Materials with long thermal lag times (for example, brick and concrete) will absorb and release heat slowly; materials with short thermal lag times (for example, steel) will absorb and release heat quickly.

Thermal mass

Thermal mass, or the ability to store heat, is also known as volumetric heat capacity (VHC). VHC is calculated by multiplying the specific heat capacity by the density of a material:

• Specific heat capacity is the amount of energy required to raise the temperature of 1kg of a material by 1°C.

• Density is the weight per unit volume of a material (ie how much a cubic metre the material weighs).

The higher the VHC, the higher the thermal mass.

Water has the highest VHC of any common material. The following table shows that it takes 4186 kilojoules (kJ) of energy to raise the temperature of 1 cubic metre of water by 1°C, whereas it takes only 2060kJ to raise the temperature of an equal volume of concrete by the same amount. In other words, water has around twice the heat storage capacity of concrete. The VHC of rock usually ranges between brick and concrete, depending on density. Most common building materials with high VHC also tend to be quite conductive, making them poor insulators.

Thermal lag

How fast heat is absorbed and released by uninsulated material is referred to as thermal lag. It is influenced by:

• heat capacity of the material

• conductivity of the material

• difference in temperature (known as the temperature differential or ΔT) between each face of the material

• thickness of the material

• surface area of the material

• texture, colour and surface coatings (for example, dark, matte or textured surfaces absorb and re-radiate more energy than light, smooth, reflective surfaces)

• exposure of the material to air movement and air speed.

To be effective in most climates, thermal mass should be able to absorb and re-radiate close to its full heat storage capacity in a single day–night (diurnal) cycle.

In moderate climates, a 12-hour lag cycle is ideal. In colder climates subject to long cloudy periods, lags of up to 7 days can be useful, providing there is enough solar exposed glazing to ‘charge’ the thermal mass in sunny weather.

Embodied energy

Some high thermal mass materials, such as concrete, cement-stabilised rammed earth, and brick, have high embodied energy when used in the quantities required. This highlights the importance of using such construction only where it delivers a clear thermal benefit. When used appropriately, the savings in heating and cooling energy from the thermal mass can outweigh the cost of its embodied energy over the lifetime of the building. Consideration should be given to using high thermal mass materials with lower embodied energy, such as water, adobe or recycled brick.

Why is thermal mass important?

When used correctly, materials with high thermal mass can significantly increase comfort and reduce energy use in your home. Thermal mass acts as a thermal battery to moderate internal temperatures by averaging out day−night (diurnal) extremes.

In winter, thermal mass can absorb heat during the day from direct sunlight. It re-radiates this warmth back into the home throughout the night.

In summer, thermal mass can be used to keep the home cool. If the sun is blocked from reaching the mass (for example, with shading), the mass will instead absorb warmth from inside the home. You can then allow cool breezes and convection currents to pass over the thermal mass overnight to draw out the stored energy.

Conversely, poor use of thermal mass can reduce comfort and increase energy use. Inappropriate thermal mass can absorb all the heat you produce on a winter night or radiate heat to you all night as you try to sleep during a summer heatwave.....