"Summertime, and the livin' is easy ..." - until the temperature rises and your house feels hot enough to roast a turkey in. That's when you start thinking about air-conditioners. Before desperation drives you to make an impulse buy, turn on the fan and take a minute to read our Air-Conditioners Buying Guide.

Mistakes Air-Conditioners Buyers Make 

The biggest mistake consumers make with air-conditioners is in the cooling capacity of the unit they choose. Going on the theory that if the unit is powerful enough to cool off a large house, it can cool a small one even better, some homeowners overspend on a product that is more powerful than they need. Others think that a cheaper model will be just as efficient as a more expensive model and cheaper to run. These are both fallacies. Keep these points in mind before you make your decision:

• If the air conditioner cools the house or room to the desired temperature too quickly, it cannot dehumidify a room efficiently.

• An air conditioner that is too efficient for the room will shut down and turn on more frequently. This will waste significant amounts of energy.

• Air conditioners that are too small for the area that is to be cooled will run continuously and consume excessive power.

How to Find the Right Capacity Air Conditioner

When you look at the "Cooling Capacity" specifications for air-conditioners, you will notice that they are divided into groups according to their kilowatt output. At the low end of the scale are those of less than 5kW. At the high end are some that have 20-25kW capacities. You are right when you guess that the higher the kilowatts, the bigger the area the unit will efficiently cool. But how do you calculate the capacity that's right for you or do you just take a punt?

The Australian government energy rating website (http://www.energyrating.gov.au/acl.html) recommends following this rule of thumb:
• 125watts (0.125kW) per square metre of floor area to be cooled in living areas
• 80 watts (0.080kW) per square metre of floor area in bedrooms
Let's say you've got a living room that measures 6mX5m or 30 square metres. Multiplying 0.125kW by 30 comes to 3.75kW. Other factors will include the ceiling height, whether the room is exposed to the sun and how well insulated the room is. Even allowing for negative factors, if all you are trying to cool is that one 6X5 room, then a Cooling Capacity of less than 5kW should do just fine for you.

The Cooling Efficiency Rating

The best indicator of an air conditioner's efficiency is its "Cooling Efficiency" rating. This six star rating system was designed to make home appliance decisions easier and to promote energy conservation. It is still a handy guide, but has been complicated somewhat by the introduction of a tougher rating system.

You will see the Cooling Efficiency rating on many of the air-conditioners listed on our site has the words "old" or "new" in parentheses before their stars. An air conditioner with an old rating of 5 (very efficient) may have a rating of only 2.5 on the new system. When comparing air conditioners, be sure you are comparing them by their equivalent (old or new) ratings.

Don't discount the importance of the Cooling Efficiency rating guide. By purchasing an air conditioner with a higher rating, you can save $25 - $50 on your energy bill every year and significantly cut back on your share of harmful environmental emissions.

Air-Conditioners: The Choices

Cooling Air-Conditioners or Reverse Cycle Air-Conditioners?

One of your first choices will be between air conditioners that cool the air only and reverse cycle air-conditioners. While the heating capacity and therefore kilowatt usage of reverse cycle air-conditioners is greater than their cooling capacity, this is not an important factor to consider. If you regularly use a heater during the colder winter months, it makes sense to spend a little more and buy a reverse cycle air conditioner.

Ducted or Wall Hung?

Your next choice will be between ducted split systems, wall hung split systems and window or wall mounted single unit systems. Single unit systems are the big units you see stuck outside of windows all over Australia during the summer months. There are still some of these on the market, but generally speaking, you're better off with a split system unless you find a really good deal. Split systems are a little more expensive, but are quieter and less bulky than the old-style boxes.

Choose a ducted split system if you want to air condition your entire house. The cooling system in ducted systems is located in one isolated area and the air transferred to the rooms via air ducts. These systems are expensive, ranging from $2000-$10,000 plus installation.

Wall hung split systems are for single room cooling and/or heating only and in Australia are by far the biggest sellers. The most expensive wall hung split systems cost around $4000, while most models average between one and two thousand dollars.

Other Features to Consider

Inverter

An inverter (sometimes called variable speed drive) varies the compressor speed. This narrows the range of speeds the compressor needs to run at in order to maintain a consistent room temperature. According to many experts, air conditioners with inverters increase their efficiency if they are running for long periods of time, as they do in very hot climates. However, they are not as efficient when air-conditioners are used to cool a room rapidly. This is why air-conditioners with inverters do not get the high star ratings that conventional air-conditioners receive.

Economy Mode

Economy mode is an electronic setting that maximizes the energy output for efficiency. Some say that this is an unnecessary extra, since you can accomplish the same thing by setting the thermostat to a slightly higher temperature for cooling and a lower temperature for heating.

Air Purification/Filtration

There are two main types of filtration/purification devices in air-conditioners. Active carbon filters are the most common and they are very efficient if they are replaced periodically. Electrostatic filters do not trap dust particles like active carbon filters do. Instead they separate them from the air and deposit them in a container. Because of this, they only need to be cleaned occasionally, but never replaced.

Electronic Controls

Electronic controls allow you to make more precise temperature adjustments than old-style "Low-Medium-High" controls. These not only enable you to fine-tune your comfort level, but also can help you save on energy consumption. A difference of just a few degrees can make a big difference in energy consumption.

The Final Word

The final word on air conditioners is this: Do your homework before you buy. Air conditioners are expensive to buy, expensive to run and consume enormous amounts of energy. This has been proven more than once when entire cities have had blackouts on hot summer days simply because all the city's air conditioners were running at once. If everybody had attempted to lower their energy consumption by as little as 10%, these blackouts could have been avoided and all of those consumers could have enjoyed their air conditioning and saved on their energy bills at the same time.