A ducted evaporative air conditioning system is a popular and efficient cooling choice for your home, office, or business. It cools your whole building at a fraction of the running costs of other systems, significantly reducing your energy costs. In South Australia’s hot, dry summer climate, a ducted evaporative system is particularly well-suited due to its use of water to create a natural cooling effect via evaporation.

Understanding Ducted Evaporative Air Conditioning

What is an Evaporative Cooler and How Does it Work?

An evaporative cooler is a type of air conditioning system that cools air through the evaporation of water. Unlike other air conditioners that use refrigerants and compressors, evaporative coolers utilise the natural process of water evaporation to reduce air temperature. When warm air passes over water, the water absorbs heat and evaporates, leaving the air cooler. Here’s how it works:

1. AIR INTAKE – External vents draw warm, dry air into the evaporative cooler.
2. COOLING PROCESS – The air passes over water-saturated cooling pads inside the unit. As the warm air moves through these pads, water evaporates, absorbing heat and lowering the air temperature.
3. AIR DISTRIBUTION – The cooled, moist air is distributed throughout the home via ducts.
4. VENTILATION – For the system to work efficiently, some windows or doors need to be open slightly to allow the warm air inside the home to escape, ensuring continuous airflow.

Once-Through Cooling vs. Closed Process Cooling

Evaporative cooling is a “once-through” process, meaning it continuously brings in fresh air from outside and cools it before expelling it. To function effectively, the used air must flow out through open windows and doors as new air enters. This differs from refrigerated cooling systems, which are “closed” processes that work best in a sealed environment with doors and windows closed. They recirculate the same air within the home, repeatedly cooling and dehumidifying it.

Importance of Proper Ventilation

Proper ventilation is essential for evaporative cooling to be effective. The system works best when there is a clear path for air to flow from the cooler to the outside of the home. This involves keeping some windows and doors open to allow the hot, humid air to escape and be replaced with cooler air. Guidelines for optimal ventilation vary depending on manufacturer specifications, but the opening size should generally be approximately twice the size of the cooling unit’s exhaust vent. Here are some guidelines:

• WINDOW AND DOOR OPENINGS – Evaporative air conditioners work by pulling air into the room, so opening your windows about 5cm should be enough for an effective cross breeze. If you find it’s not getting cool enough, try opening the doors to the outside that much as well.
• CROSS VENTILATION – Open windows or doors on the opposite side of the home from the cooler to maximise airflow.
• ADJUSTABILITY – Adjust the openings based on the cooler’s airflow capacity and the cooled area size.

Sizing the System to Your Home

The effectiveness of a ducted evaporative air conditioning system heavily depends on accurate sizing. It’s essential to calculate the size of the area or home to be cooled to determine the system size. Undersized units will struggle to cool the space, while oversized units can lead to higher energy consumption. Our consultants consider the following whilst working out the correct sized evaporative air conditioning system:

• SQUARE FOOTAGE – Determine the total square footage of the area to be cooled.
• COOLING CAPACITY – Evaporative coolers are rated by how much air they can move, measured in cubic feet per minute (CFM). A general guideline requires about 20 to 40 CFM per square foot of living space.
• CLIMATE CONSIDERATIONS – South Australia’s hot, dry climate is ideal for evaporative cooling, but a more powerful unit may be required during peak summer heat.

Advanced Features in Modern Ducted Evaporative Air Conditioning Systems

Self-Cleaning Water Pumps

Newer evaporative cooling systems often include self-cleaning water pumps. These pumps assist with:

• AUTOMATIC MAINTENANCE – Clear blockages and debris automatically, reducing the need for manual cleaning.
• ENHANCED EFFICIENCY – Maintain peak performance by preventing clogs that can reduce airflow and cooling capacity.
• EXTENDED LIFESPAN – Regular self-cleaning helps extend the life of the pump and the cooling system.

Water Management System

Most modern ducted evaporative cooling systems offer an inbuilt water conditioner that keeps the water that the system uses clean, increasing its cooling effectiveness and reducing unnecessary water wastage.

Variable Fan Speeds

A variable-speed fan will help you have greater control over the cooling process, enabling you to adjust the airflow to suit your comfort needs. This can result in improved energy efficiency and cost savings as the system can operate at lower speeds when full power is not required. Variable-speed fans also allow for quieter operation and reduce noise levels within the home.

Standard vs. Inverter Models

Ducted Evaporative air conditioners are available in standard and inverter models. Standard models operate at a fixed speed and cooling capacity, which means they are either fully on or off, resulting in less adaptable performance. Inverter models feature variable speed motors that adjust their output based on real-time cooling demands. This ability to modulate cooling power enhances comfort by maintaining indoor temperature.

Inverter models also use significantly less energy than standard models, which can help you save money on energy bills and makes them a more environmentally friendly option. Since inverter models are clearly the better choice, Glow recommends these units for your ducted evaporative air conditioning system.

Annual Energy Cost Comparison: Evaporative vs Refrigerated

Ducted Evaporative cooling can use up to 67% less energy annually than refrigerated air conditioning, depending on the size of the area to be cooled and the air conditioner model. Sustainability Victoria conducted an extensive home air conditioning cost comparison, comparing approximate annual running costs in an average existing (pre-2005) house in a mild climate and average cooling usage. These figures were last updated in December 2022:

• Standard Ducted Evaporative Cooling: Approximately $33 annually
• Inverter Ducted Evaporative Cooling: Approximately $20 annually
• 1-Star Ducted Refrigerated Air Conditioning (not zoned): Approximately $201 annually
• 3-Star Ducted Refrigerated Air Conditioning (not zoned): Approximately $134 annually

Installation Considerations

Cost

The cost of installing a ducted evaporative air conditioning system varies depending on these factors:

• Size of the home
• Configuration complexity

Other Considerations

Here at Glow, we always discuss our recommendations and the installation process based on your requirements and the layout of your home. Common considerations when designing your ducted evaporative air conditioning system that can impact both cost and feasibility include how the unit will be mounted to the roof, the structural integrity of the roof, the ducting pathway in your roof, and the locations of the outlets.

Enhanced Functionality

Add-ons can enhance the functionality and convenience of your evaporative cooling system:

• WIFI CONTROLLER – Allows for remote operation and monitoring via a smartphone app.

Benefits of Ducted Evaporative Cooling

Cost-Effectiveness

Ducted evaporative air conditioning is very cost-effective for homeowners, particularly in dry climates like South Australia. Since the system uses the natural water evaporation process to cool the air, it consumes significantly less energy than traditional refrigerated air conditioning systems. The reduced energy consumption directly translates to lower utility bills, offering substantial savings over time.

Additionally, the initial installation costs of evaporative cooling systems are generally lower, ranging from $2,500 to $6,000+, depending on the home’s size and configuration. With fewer mechanical components, evaporative air conditioners also incur lower maintenance costs.

Less Moving Parts

Fewer mechanical parts in the home’s ducted evaporative air conditioning systems offer several benefits. First, it reduces the likelihood of mechanical failures, leading to fewer disruptions to home comfort. Second, there are lower maintenance requirements and costs since fewer parts need regular servicing or replacement. Third, because the system operates more quietly, it helps to create a peaceful indoor environment.

Environmentally Friendly

Unlike refrigerated air conditioners, evaporative coolers rely on the natural process of water evaporation, which eliminates the need for harmful refrigerants that contribute to greenhouse gas emissions and ozone layer depletion. This method uses fresh outside air, ensuring a continuous supply of clean, cool air and improving indoor air quality.

Evaporative systems consume significantly less electricity – up to 67% less energy than their refrigerated counterparts – reducing the household’s carbon footprint. The lower energy demand not only reduces fossil fuel consumption but also decreases overall environmental impact.

Effective Cooling in Dry Climates

Ducted evaporative air conditioning is most effective in hot, dry climate conditions. Because of the evaporation process the system is based on, it provides substantial cooling performance in South Australia’s warmer weather.

Fresh Air Circulation

Ducted evaporative air conditioning constantly introduces fresh air from outside while cleaning any impurities and pollens from it as the air passes through the filter pads. This purified air is continuously refreshed within the home, as open doors and windows assist in natural ventilation—meaning air is never recirculated or dried out.

How Much Water Will It Use?

The water consumption of an evaporative cooler depends on the heat and humidity levels. In Adelaide, typical rates range from 67 to 116 litres per hour, according to a 2009 study. The water usage varies, with higher consumption on hotter and drier days.

Selecting the right ducted evaporative air conditioning system for your home can be complex, even with ample information. Consider consulting a specialist in ducted evaporative cooling systems, such as Glow, for expert guidance. Our team will assess your needs, recommend the most suitable system for your home, and address any questions. Contact our friendly staff today at 8397 6100 to schedule a convenient appointment.