On the hottest summer days, you may need to use a cooling system to stay comfortable. Compare the pros and cons of the different options.
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If you can't cool your home using passive cooling techniques such as shading and natural ventilation, it's important to choose the most appropriate active cooling system for your needs. By choosing a system that is the right size for your home, while responding to the way you live in your space and your homes local climatic conditions you can avoid paying for energy you don't need.
If you’re looking to install a cooling system in your home, you should consider this as an opportunity to choose the most efficient technology available that works for the size of the space you want to cool and won’t cost you the earth to run.
When selecting the right cooling system for your home, it is important to compare different models as efficiency can vary greatly.
When purchasing a ceiling fan, compare the rated power consumption of the different models and the number of fan speeds available. Fans with DC motors have a lower power consumption than fans with AC motors, and often have a wide range of fan speeds.
Evaporative systems aren’t subject to energy labelling requirements, so speak to your installer about the features of different models, including their power consumption and water consumption. Inverter models have a lower power consumption than standard models when operating at lower fan speeds, so generally have a lower overall energy consumption.
For air conditioners, use the Energy Rating Label to compare the efficiency of different models. Their efficiency is rated from 1 to 10 stars; the higher the star rating the more efficient they are and the lower the running costs. Most air conditioners sold are now reverse-cycle, and the labels provide a rating for both their cooling and heating performance. The cooling star rating is shown in the blue band and the heating star rating in the red band.
If you only require cooling in a bedroom at night, or in a living room that doesn’t get too hot during the day, a ceiling fan might be all that is required to keep you comfortable. These are relatively cheap to install and have low running costs. They are also an option to consider in larger living areas, as they may be all that is required to keep you comfortable on all but the hottest days.
If you require cooling in one, or a number of, living area(s) then a room split or multi-split system could be a good option. In this case, it’s worthwhile getting a reverse-cycle system that can provide both cooling in summer and efficient, low cost, heating in winter. Use the Energy Rating Labels to identify models that are efficient at both cooling and heating.
If you require cooling in all, or large areas, of your home, then one or several multi-split systems, or a ducted refrigerative or evaporative system will be required. A reverse-cycle multi-split system will be more efficient and provide more flexibility than a ducted reverse-cycle system. Reverse-cycle multi-spilt and ducted air conditioners can provide cooling and heating in the one unit, whereas houses with ducted evaporative cooling will require a separate heating system. Evaporative systems remain idle for much of the year and if not winterised correctly, can significantly increase winter heating costs.
Most room and multi-split system air conditioners use inverter technology – this uses a variable speed compressor rather than the old-style compressor that is either fully on or off. Inverter air conditioners are generally quieter and more efficient than air conditioners that use the older compressor technology. Ducted refrigerative air conditioners could use either the older compressor technology or the newer inverter technology.
If you are looking to install cooling into an existing home, you should also consider this as an opportunity to replace gas heating appliances. Not only does this reduce the number of mechanical systems in your home, an efficient reverse-cycle air conditioner will save energy and cost less to run.
For effective cooling, it’s important to have a system that is sized correctly.
Ceiling fans are designed to cool a certain floor area, so you may need several fans for larger rooms or open plan areas.
Ducted evaporative coolers are sized based on their rated air flow rate in cubic metres per hour. The appropriate size depends on the volume of home (multiply the floor area by the ceiling height to get this in cubic metres) that you are cooling and the local climate, so make sure you provide this information to the supplier when getting a quote.
Air conditioners need to be sized based on the expected cooling load on hot summer days and, if a reverse-cycle system, based on the expected heating load on cold winter days. This will depend on the size of the area being cooled/heated, how well insulated, draught proofed and shaded the home is, the size and direction of windows, and your local climate. Ideally, the installer should visit your home to collect this information before providing a quote. Alternatively, you could provide them with a floor plan of your house showing the areas to be cooled/heated.