With much of NSW forecast to experience severe to extreme heatwave conditions over the coming days, NSW Health is urging residents to take steps to beat the heat.
Acting Director of Environmental Health, Dr Adi Vyas said people should take extra care to prevent heat-related illness.
“Hot weather puts a lot of strain on the body, including dehydration, and can make underlying health conditions worse,” Dr Vyas said.
“It also causes heat stress and heat stroke. People over 75 years, people with chronic medical conditions and people who live alone are particularly vulnerable.
“Plan for the upcoming heatwave by checking your fridges, freezers, fans and air-conditioners work properly. Set your air conditioning to cool; a setting of 24 degrees can keep you cool while helping to reduce electricity demand. Put jugs of water in the fridge and cool packs in the freezer. Also ensure your blinds are closed before the sun hits your windows. Plan your activities safely on hot days.
“Protect yourself during the heatwave by postponing or rescheduling your outdoor activities. Reduce the impact of heat by avoiding being outside during the hottest part of the day; keeping well hydrated with water; and looking after vulnerable neighbours and relatives.
“Signs of heat related illness include dizziness, tiredness, irritability, thirst, fainting, muscle pains or cramps, rapid pulse, shallow breathing, vomiting and confusion.”
People showing severe signs of heat-related illness should seek urgent medical attention and, in an emergency situation, call Triple Zero (000).
While everyone needs to take necessary precautions to avoid heat-related illness, NSW Health is also urging people to continue to practise COVID-19 safe behaviour during the heatwave.
“If you’re able to keep cool at home using fans, air-conditioning and closed blinds, please do so and stay at home. That way, we won’t compromise physical distancing in public indoor venues, such as shopping centres, libraries and other public buildings where people may seek respite from the heat,” Dr Vyas said.
“If you do leave your home to attend other indoor spaces, please physically distance and wear a mask in places where you cannot maintain 1.5 metres distance from others.
“It is essential to keep in touch with relatives, neighbours and friends; especially those living alone or who are isolated. Be COVID safe; check in with them through a phone call or video call.”
Living beside the sea in a place that has worked to retain its tree canopy has its advantages during the hotter weeks of the year. Just as an umbrella will shield you from blazing sun, a tree will absorb those hot rays and provide shade to keep cooler those hot tin rooves.
This week a few tips to keep things cooler around and inside the home.
If you live in an area with restricted air flow due to surrounding buildings, lots of concrete or other hard surfaces that creates radiant heat, or have a lack of trees or green breaks, the outside temperature may be hotter than that inside your home and your street may be hotter by as much as 3-4 degrees than one facing that cool ocean.
In that case you may be better shutting up your home during the hotter part of the day, drawing curtains and installing ceiling fans to create air movement. However, if your home does not have adequate insulation to keep out heat, and there is no breeze whatsoever, an air-conditioner in one room and closing off the others until a sea breeze occurs is going to be your best option for comfort and reducing energy costs. You could also shade outdoor areas around the house with plantings and shade structures to lower the ground temperature and in turn the temperature of incoming air. Even a shade cloth or large market umbrella over hotter areas will reduce the temperature being radiated against your home's walls and then inside your home.
There are also many ways you can cool your home through what is termed passive (non-mechanical) cooling, as well as hybrid approaches which utilise mechanical cooling systems. Passive cooling is the least expensive means of cooling a home in both financial and environmental terms.
Cooling buildings:
- shading windows, walls and roofs from direct solar radiation
- using lighter coloured roofs to reflect heat
- using insulation and buffer zones to minimise conducted and radiated heat gains
- making selective or limited use of thermal mass to avoid storing daytime heat gains.
Evaporative cooling by installing water features
As water evaporates it draws large amounts of heat from surrounding air. Evaporation is therefore an effective passive cooling method, although it works best when relative humidity is lower (70% or less during hottest periods) as the air has a greater capacity to take up water vapour.
Pools, ponds and water features immediately outside windows or in courtyards can pre-cool air entering the house. Carefully located water features can create convective breezes. The surface area of water exposed to moving air is also important. Fountains, mist sprays and waterfalls can increase evaporation rates. A previous DIY Ideas page on how to install water features is archived below.
Open Design to Maximise Natural Ventilation
Heat enters and leaves a home through the roof, walls, windows and floor, collectively referred to as the building envelope.
- Maximise the indoor−outdoor relationship and provide outdoor living spaces that are screened, shaded and rain protected.
- Maximise convective ventilation with high level windows and ceiling or roof space vents.
As those living in Pittwater know that cooling sea breeze is going to run inland from the east and south (southerlies), make sure you have windows facing in those directions that can be opened to allow cool air to replace hot air within a home. Opening a window on the opposite side will allow air to be drawn through the home.
In rooms where it is not possible to place windows in opposite or adjacent walls for cross-ventilation, place projecting fins on the windward side to create positive and negative pressure to draw breezes through the room.
Insulation
Insulation is critical to passive cooling — particularly to the roof and floor. Windows are often left open to take advantage of natural cooling and walls are easily shaded; roofs, however, are difficult to shade, and floors are a source of constant heat gain through conduction and convection, with only limited cooling contribution to offset it.
In climates that require only cooling or those with limited cooling needs, use multiple layers of reflective foil insulation in the roof instead of bulk insulation to reduce radiant daytime heat gains while maximising night-time heat loss through conduction and convection. This is known as the one-way insulation valve.
Reflective foil insulation is less affected by condensation and is highly suited to cooling climate applications as it reflects unwanted heat out while not re-radiating it in.
Roof space
Well-ventilated roof spaces (and other non-habitable spaces) play a critical role in passive cooling by providing a buffer zone between internal and external spaces in the most difficult area to shade, the roof.
Ventilators can reduce the temperature differential across ceiling insulation, increasing its effectiveness by as much as 100%. The use of foil insulation and light coloured roofing limits radiant heat flow into the roof space.
Hybrid cooling systems
Hybrid cooling systems are whole house cooling solutions that employ a variety of cooling options (including air conditioning) in the most efficient and effective way. They take maximum advantage of passive cooling when available and make efficient use of mechanical cooling systems during extreme periods.
Fans
Fans provide reliable air movement for cooling people and supplementing breezes during still periods.
At 50% relative humidity, air movement of 0.5m/s creates maximum cooling effect; air speeds up to 1.0m/s can be useful in higher relative humidity, but prolonged air speeds above 1.0m/s cause discomfort.
Standard ceiling fans can create a comfortable environment when temperature and relative humidity levels are within acceptable ranges. In a lightweight building in a warm temperate climate, the installation of fans in bedrooms and all living areas (including kitchens and undercover outdoor areas) significantly reduces cooling energy use.
Fans should be located centrally in each space, one for each grouping of furniture. An extended lounge/dining area needs two fans. In bedrooms, locate the fan close to the centre of the bed. Because air speed decreases with distance from the fan, position fans over the places where people spend the most time. [1.]
Before rushing out and loading up with ceiling fans or floor fans or choosing an air-conditioner it would be wise to do some research and decide what your best options are and what will suit your home's needs best.
Combining using your air conditioner with your ceiling fans will circulate and draw that cold air through those other rooms and reduce your reliance on this cooling method for longer periods and in doing so, reduce your energy costs.
Of course for residents here, opening the house as much as all your windows and doors will allow from late afternoon to early morning is beneficial if overnight temperatures fall below your homes' inside temperature, especially when that cooling sea breeze is running.
As long as you have intact flyscreens to keep out all those wing-borne insects such as mosquitoes and cockroaches, or that eight legged version of garden-house visitor, the optimum is to make use of where you are and invite that salt air inside your home.
1. Sourced from Your Home: Passive cooling - Australian Government. Retrieved from: www.yourhome.gov.au/passive-cooling
The products shown here are all sourced from Johnson Brothers Mitre 10 and are examples of what is available. Pop into one of their stores at Mona Vale, Narrabeen or Avalon and speak to their friendly trained staff about cooling your home. The Mona Vale store has water features as well as many other items that will assist in keeping you and your family more comfortable during heat waves.
