Air Conditioning

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What temperature should I set my air conditioner to?
Thermostats should be set between 25–27°C. Every 1°C lower can increase running costs by up to 15% or cost you for repairs because they do like a break every so often.

If there is a hot day forecast, then pre-cool your house the night before. This is especially effective if your house has a high thermal mass such as solid brick. This will allow your air conditioner to work at its optimum during the cool evening, saving power and wear and tear on the unit. It also allows the unit to keep on top of the heat load as it begins to warm up during the heat of the day.

How will I know if my air conditioner is operating efficiently?

Star ratings on air conditioners do not aply to systems once they have been installed. We estimate as many as 75% of all split systems installed are operating ineficiently as a direct result of poor installations, many Australians are paying far more on their energy bills than they should be as a result. Installations change the efficiency when poorly installed, a bend in pipe required n installation, lack of understanding of the “whole” system by plumbers or electricians and in far too many cases refrigerant leaks will all contribute to poor efficiency of a system. Refrigeration mechanics are trained to prevent these types of occurances and can do an efficiency test for you on completion of installations and even on any existing systems. Checkout our energy efficiency program here.

How much does it cost to have a split system air conditioning installed?

A standard back-to-back split system installation including wiring and appropriate permits will cost approximately $600 to $800 depending on season and quality of work. You may find them cheaper but you get what you pay for. The potential exists for a poor installation to cause expensive repair costs down the track and that should be considered. A non-standard split system installation with brackets, ductwork, a long run, or additional power requirements will obviously cost more. ARMA will only ever recommend refrigeration mechanics who have been appropriatley vetted, meeting trade qualifications and business requirements and hold the ARMA smart card You should also get a certificate of compliance for the electrical work. Most states require electricians to install the wiring connecting the indoor and outdoor units, ask your refrigeration mechanic what the laws are in your state.

Who is the tradesperson to install an air conditioner?

All installations are not equal – be very careful on which contractor you use to install your air conditioner, ask about what materials they use and what advantages their chosen product have, if they don’t know or tell you they are all the same they are likely using inferior materials. Why spend thousands on your air conditioner and then save a few dollars having it poorly installed? Most refrigerated systems fail due to poor installation practice not defective units. A good way to protect yourself is to use a knowledgeable refrigeration mechanic, ask questions, you are making a big investment. Also make sure that your installer is actually a refrigeration mechanic, scan their ARMA smart card and check their qualifications, only refrigeration mechanics can repair your unit and properly commission it. There are many plumbers and electricians who install split systems as a side line that would have no idea how your units internals actually work let alone properly commission your unit for maximum performance and efficiency (there are a select few that do). Many cowboy installers and low quality installers do not spend the time planning, installing and commissioning units and it will cost you in the long run, not only in failures but in decreased efficiency.

What is an inverter?
The difference between inverter and non inverter is the inverter units can alter their speed in response to cooling demand. Some units have an initial over-speed period where they will run at a slightly higher capacity for a set time to pull down the temperature of a hot room. When they reach the set point temperature they can reduce capacity to maintain that level without cycling as much as a normal unit would. This saves power although it’s arbitrary as it would still take a while to recoup the increased purchase costs.

What are multi-head splits
They are the best option for whole house cooling where you can’t run ductwork, i.e. a slab floor with a flat or cathedral roof. Or where efficiency, comfort and aesthetics are important, consider bulkhead mounted split systems, the ultimate in control, efficiency and comfort but more expensive to install.

What are ducted systems
Most home ducted systems are in the form of split ducted systems. There are two main types used in residential cooling.

Add-on cooling which is most competitive in terms of price but is a compromise due to sharing heating components and ductwork. Air conditioning is best installed in the ceiling as cool air falls, but most ducted heating is in the floor and there’s a minimum duct size of 6” for heating whereas cooling requires 8” so ducts have to be redone.

Dedicated ducted splits are slightly more expensive to install but offer the benefit of being an engineered package. You also have more choice of manufacturers than add on solutions.

Either way you can zone the ducts to allow a smaller unit to cool sections of a house or to turn off unwanted sections on a whole house setup. In my opinion ducted is preferable to multi head splits as they have fewer parts, fewer electronics and fewer potential refrigerant leaks.

What are portable air conditioners?
Most portable air conditioners are compromised by their design and are best chosen if no other alternative is available.

There are two distinct types. Some have a remote condenser which can be hung out a window in the same way a split system works. In theory this is the best solution but in practice it can be awkward. Others have a ducted condenser which blows conditioned air out a duct. This is less than ideal because you lose conditioned air while the duct also radiates heat back into the room. Neither are great as they have the compressor in the room, so they’re far louder than a comparable split. They are also more expensive to buy than a split although they do generally work out cheaper as they don’t require professional installation. Some ducted units require water to operate properly as they use water to cool the condenser. Such units use the waste water condensed from the air but will operate more efficiently if additional water is added.

What are evaporative coolers?

An evaporative cooler requires doors or windows open to allow airflow. As a guide, the entire volume of the room should be flushed through every two minutes (or around 30 air changes per hour).

During winter, older ducted units on the roof should have covers placed over them and ceiling vents closed to stop heat loss. Alternatively, consider purchasing a unit with a motorised damper. (many new units have a automatic spring or gravitational shutter)

Portable evaporative coolers
Suitable for small rooms (up to 25m2).
Best positioned near an open window or external door with an opening on the opposite side of room.
Water consumption can be up to four litres per hour. Water needs to be topped up regularly.