As the most environmentally friendly and cost-effective method to cool buildings, passive cooling systems are setting the new standard for comfortable and sustainable living here in Australia.
Passive cooling reduces the need for mechanical systems like air conditioners that increase your energy consumption and monthly bills. These systems can also be tailored to any property size, from small apartments to larger homes, ensuring that you remain comfortable wherever you are.
In this comprehensive guide, we’ll explore the ins and outs of passive cooling systems, including the key benefits, and how you can make the most of these natural ventilation techniques within your home.
What is Passive Cooling?
Passive cooling, or evaporative cooling, involves minimising heat gain and enhancing heat loss to keep your home cool and comfortable. This is particularly important in climates that are hot and humid all year round.
The concept of a passive house was originally developed in 1991 by physicist Wolfgang Feist with the aim of efficiently heating European homes. However, these techniques also offer popular and effective solutions for the cooling of buildings during our sweltering Australian summers.
Passive cooling uses design choices to control the temperature of your home, such as installing effective thermal insulation or adding air conditioning to lower the air temperature.
Its main design principles therefore include:
- Airtightness– Gaps in a building’s air barrier can cause significant heat loss. To achieve passive cooling and reduce air exchange, your home must therefore have a roof, floor windows, and exterior walls that are constructed to be airtight.
- Thermal Insulation: Insulation made from low-conductivity materials creates a separation between the hot outdoor air and the cooler indoor environment.
- Mechanical Ventilation Heat Recovery: MVHR systems are designed to improve indoor air quality without needing to open the doors or windows. They bring fresh air in and also eliminate any pollutants, carbon dioxide, moisture, or odours from your home.
- High-Performance Windows: Airtight double or triple-glazed windows play a key role in minimising radiation during the summer, which significantly cools your house down.
- Thermal Bridge Free Construction: Homes designed with passive cooling in mind should avoid thermal bridging, an unintended path of heat flow. Thermal bridging also increases the risk of condensation and encourages mould growth.
What Are the Benefits of Passive Cooling Systems?
Along with creating a durable property, using passive cooling techniques creates significant energy savings and offers numerous other benefits for your home. Here are just three advantages of these energy-efficient systems:
- Helps to Reduce Energy Costs: Passive cooling can reduce our energy consumption for heating and cooling by up to 90%. Combine with mechanical cooling systems that you may already have in your home, such as air conditioners, and you’ll find that your dependence on these systems decreases significantly.
- Enhances Home Comfort: Living in a home with a constant air temperature is much more pleasant than spaces that become too hot in the summer, yet freezing throughout the winter. Passive cooling strategies also provide fresher, cleaner air that stops your home from feeling stuffy or stale.
- Eco-Friendly: Relying less on mechanical systems to produce allows you to lower your carbon footprint, by using fewer fossil fuels to produce cooler air and minimise heat gain.
How to Introduce Passing Cooling Into Your Home
A home that effectively incorporates all five principles into its design can achieve optimal passive cooling and experience many of the benefits we’ve explored above.
Here are some of the key passive cooling techniques to try if you’re hoping to filter hot air out of your home:
Create Shading
A good shading system should prevent excess heat energy from moving into indoor spaces and making your home too warm, which increases the need for air conditioning.
This energy primarily comes from sunlight, which is absorbed by your home’s roof, walls, and windows. However, it can also enter your living spaces through air leakage and heat-generating appliances.
You should therefore consider using adjustable shade screens, window shades, external blinds, or simply trees and vegetation that stop sunlight from streaming through glass windows and doors.
This helps to minimise solar radiation and improve the energy performance of your building.
Encourage Convection
One of the most basic, yet effective passive cooling techniques that you should consider within your home is convection. This is based on the idea that warm air rises to the ceiling, while cool air falls.
Convection therefore makes the most of natural ventilation strategies, such as installing roof ventilators or positioning windows to help hot air escape through cross ventilation.
Windcatchers are another great way to harness the power of cross ventilation, as they capture the cool breeze and vent warm indoor air. They are typically located on the roof and allow air to enter through a series of openings, therefore reducing the indoor temperature by approximately 10 degrees.
Ventilation System
As we’ve already mentioned, one of the key principles of passive cooling is an airtight construction. Without any ventilation, your home could therefore become stuffy and hot during the warmer months, which is where installing a natural ventilation system like RapidRidge comes in.
RapidRidge combines the benefits of a dry fixed roof with ventilation to facilitate natural cooling across the entire roof, which reduces heat transfer through the ceiling into your living space.
By installing an eaves vent on the roof, RapidRidge creates an opening for fresh air to enter and warm air to escape, while preventing the sun’s rays from warming your property.
This allows your home to remain cool while reducing energy costs by as much as 43%. RapidRidge is also incredibly easy to install, with no maintenance required.
Visit the RapidRidge website to find out how this energy-efficient system facilitates passive cooling and extends the lifespan of your roof.