How to choose the best cooling solution for your home
We ask the experts to explain the pros, cons and costs of the most common cooling systems.
Choosing a cooling system for your home can leave you hot and bothered. There’s a wide variety of devices and systems available to help you keep your cool when temperatures climb, from inexpensive desk-top fans to state-of-the art, smart air-conditioning units you can control from your phone. But which is best for your home and individual circumstances?
Whether you want to chill a large space, cool a single room or just need something to provide relief at your workspace, we asked the experts to explain the pros, cons and costs of the most common cooling appliances on the market.
RACV Solar’s regional manager of heating and cooling, Tom McKenzie, says air-conditioners have come a long way in recent years in terms of energy efficiency. “An old unit might need around six kilowatt hours of electricity to cool an average-sized house, while modern air-conditioners can cool the same house for less than a third of that,” he says. So, if your air-conditioner is more than 15 year’s old, it might be worth taking advantage of state government incentives to upgrade to a newer, more energy efficient system. The Victorian Energy Upgrades program offers householders rebates of up to $1100 for replacing old systems with new energy efficient, reverse cycle air conditioners.
When choosing a new system be sure to check the energy star ratings on the Federal Government’s energy-rating website. The more stars, the cheaper the running costs. And remember, if you have roof- top solar, you can run the air-conditioner during the day using power generated from your roof, without running up your power bills.
Wall-mounted reverse-cycle split systems
One of the most energy efficient cooling options for your home, these all-in-one heating and cooling units, pump hot air from inside your home to an external refrigeration unit in summer and return chilled air inside. In winter the same system heats the air before pumping it back inside.
Although new split systems are relatively cheap to run, the Australian Energy Foundation warns that for every degree you lower the thermostat, you’ll add 10 per cent to the running cost – with minimal extra benefit to your comfort level. The AEF recommends setting the thermostat at 23 to 26 degrees in summer, to minimise your energy usage.
- Upfront cost: Each unit will cost at least $2000, including installation, to cool up to 20 square metres, and more than twice that for a powerful unit that can cool 80 square metres. So, if you want to cool more than a couple of rooms, you may be better off investing in a single ducted system that can chill the whole house.
- Running costs: From 36 to 70 cents an hour, depending on the unit’s energy rating and size of your room. Of course, if you have rooftop solar, you can power your air-con during the day without running up your energy bill.
- Pros: The same system will heat your house in winter.
- Cons: Each unit will cool just one room so if you want to cool the entire home, you’ll need a unit for every room.
- Best suited for: Cooling one or two selected rooms – such as a bedroom and a living room.
Ducted split systems
These work in a similar way to wall-mounted split systems, but pump chilled air back into the house via ducts in your floor or ceiling. They are also fairly energy efficient but more expensive up front, costing $10,000 or more to buy and install. Many ducted systems now come with ‘smart’ features that allow you to adjust the temperature and turn cooling on and off in certain rooms or sections of your house remotely using your smartphone or laptop. This allows you to turn on the air-con remotely to keep your home cool before it really heats up. Not only will you arrive home to a comfortable temperature, you'll avoid the extra energy use needed to chill a stinking hot house.
- Upfront costs: Smaller ducted systems start at around $10,000, including installation.
- Running costs: Expect to pay around 36 to 70 cents per hour, per room, or $2.45 to $3.45 per hour if you’re cooling a whole 200-square-metre house.
- Pros: You can choose to cool the whole house, or just the rooms you’re using.
- Cons: Relatively high up-front investment.
- Best suited for: Larger family homes where you want to cool several rooms at once.
Window or wall box cooling-only air-conditioners
If you’re on a tight budget and want to cool a single room, a window or wall-mounted box air-conditioner is a good option, according to consumer advocate Choice. Although less energy efficient than split systems, they cost less up front – you can buy a small unit for as little as $400. Smaller units can be plugged into a normal power point so there are no installation costs, although larger units may need additional wiring.
- Upfront cost: From $400 to $1100, plus installation costs, if necessary.
- Running costs: These are less energy efficient than split-system air-conditioners, so will cost more to run.
- Pros: Small units can plug into a normal power point, so there are no installation costs.
- Cons: Only capable of cooling small areas of up to 35 square metres.
- Best suited for: Those on a tight budget who only need to cool a small area, and renters – window-mounted units can be taken with you when you move.
While these offer the convenience of moving from living room to bedroom, or whatever room you happen to be in, they can be cumbersome to move around and are relatively expensive to run.
- Upfront cost: $300 to $1300.
- Running costs: Origin Energy says a portable unit can cost almost $70 to $200 more to run a year than a modern split-system or ducted air-conditioning unit.
- Pros: They can be moved to cool whatever room you are using.
- Cons: Less energy efficient and effective than alternative air-conditioners.
- Best suited for: Renters who want to cool a single room at a time, and are unable to install a fixed unit.
Evaporative ducted cooling
These use a fan to draw warm air from outside through a series of wet filter pads in a unit – usually installed on the roof – which cools the air and pumps it back through the house via floor or ceiling ducts. RACV Solar’s Tom McKenzie says evaporative systems can cool a house by an average of 10 degrees, so if the outside temperature is 37 degrees, inside can be cooled to a comfortable 27 degrees. Many people report that evaporative cooling provides a more comfortable, natural-feeling cool than refrigerated air-conditioners, and Tom says they use about half as much electricity as an equivalent ducted split-system air-conditioner. However, they do use a lot of water and do not work well in humid climates. You’ll also need to keep some doors and windows open when in use to enable constant air circulation.
- Upfront costs: $4500 to $6000.
- Running costs: Evaporative coolers use about half the energy of a similar-sized ducted split-system air-conditioner, but they guzzle water which will add to the running costs.
- Pros: Gentle cooling that won’t dry out the air or irritate your eyes, throat or skin.
- Cons: The systems use around 25 litres of water an hour, which can quickly add up and exceed Melbourne’s average water use of 162 litres per person a day.
- Best suited for: Dry climates, and people who find the dry heat of refrigerative air-conditioning irritates their eyes or skin.
Regardless of the type of air-conditioner you choose, it’s important to get the right size for your needs. Buy too small a system and it won’t do its job; too big and you’ll be wasting money and using excess energy. When calculating what size you need, Choice says there are four things to consider:
- Room size: Not just the floor space, but the ceiling height. Rooms with high ceilings need more energy to cool them.
- Insulation: Poorly insulated rooms will need more power to keep things cool.
- Location: The hotter the climate, the more air-conditioning power you’ll need.
- Orientation and windows: A room with large north or west-facing windows gets hotter and will therefore require a more powerful system than a room with shaded, southern-facing or east-facing windows.
Fans are an inexpensive option to help make your home more comfortable in summer. Although fans don't actually lower the room temperature, they make you feel cooler as air circulates over the skin. The Australian Energy Foundation suggests using a fan along with your air-conditioner to help circulate chilled air so you don’t need to set the air-con thermostat quite so low
Pedestal and desk fans
Inexpensive to buy and cheap to run, desk fans are great for those working from home, while pedestal or tower fans can be directed to the part of the room you’re using – such as the couch or bed – to help you feel cooler.
- Upfront costs: You can buy a small fan for less than $20.
- Running costs: From as little as two cents an hour, according to Sustainability Victoria.
- Pros: No installation, simply plug into a power point.
- Cons: They don’t actually lower the room temperature but will make it feel three degrees cooler.
- Best suited for: Those on a limited budget.
Although less effective than split system or evaporative air-conditioning when it comes to cooling a room, ceiling fans tend to work better than pedestal or desk fans as they circulate more air over a wider area to make the whole room feel cooler. When used in conjunction with air-conditioning they help circulate chilled air around the room. They cost more to run than pedestal fans, but are still a relatively inexpensive option, costing $13 to $25 a year to run, according to Choice, compared with $150 to $300 for air-conditioning.
- Upfront costs: From $200 to several hundred dollars, plus installation.
- Running costs: A fan with an AC motor fans costs $25 a year to run, while a DC motor averages at $13.
- Pros: Cheaper to run than air-conditioning.
- Cons: Less effective on really hot days.
- Best suited for: Use on moderately warm days or in conjunction with air-conditioning to circulate chilled air when temperatures soar.
These futuristic-looking fans have hidden blades that draw in and push out air to create a breeze. The lack of visible blades means they are easy to clean and safer if you have young children in the house. According to Choice, they cost around $30 to run over summer, a bit more than a ceiling fan but less than the $150 to $300 it costs to run an air-conditioner.
High-end brand-name versions can cost as much as $500 to buy, but you can pick up a lesser-known brand for as little as $50.
In a comparison test, Choice found that an $89 department-store pedestal fan out-performed a high-end bladeless version for airflow and noise.
- Upfront costs: $50 to $500-plus.
- Running costs: Around $30 over summer.
- Pros: Easy to clean and safer than a fan with exposed blades.
- Cons: Less effective than a cheaper pedestal fan, according to Choice.
- Best suited for: Those with young children or who prefer the clean lines of a bladeless device.