Frequently Asked Questions

Air Conditioner Size Selection Guide

Your air conditioning sizing requirements will vary subject to a number of factors. These factors include the aspect positioning of your house, the material the house is made of such as brick veneer, double brick or weatherboard. The location and size of windows and the covering on these windows and whether the house in insulated has a large bearing on the sizing. All of these factors combined with the region you live in can vary the air conditioning requirements by up to 20% between a house in Northern and Southern Australia.

To be sure you purchase the unit that best suits your situation we recommend you discuss your specific requirements with your nearest retailer to be found in our Retailers section on this site or qualified installer.

For split system Size Selection Guide click here

Q: What are the benefits of Air Conditioning?

The major benefit is to give a comfortable environment at home or the office throughout the year. An air conditioning unit has a number of functions including heating, cooling, dehumidifying and fan only. This will enable you to set the temperature and the unit will cool or heat as required or in the case of dehumidify, the unit will get rid of the moisture in the air without dropping the room temperature which is beneficial for those with Asthma.

Q: What are some of the types of air conditioners available?

SINGLE ROOM AIR CONDITIONERS - One-piece unit, which must be installed in an external wall or window. These can be available in Reverse Cycle or Cooling only.

SPLIT SYSTEMS – Generally two piece units (but can be more in the case of multi splits) consisting of an Indoor and Outdoor Unit. Split Systems are available as Reverse Cycle or Cooling only. These are available in fixed speed or inverter. The Midea inverter range distributed by CASTEL use DC inverters to give infinite control over temperature maintenance along with energy saving efficiency.

DUCTED SYSTEMS - Ducted air conditioners are able to condition whole or part of a house. This is a highly specialised area and should only be undertaken by a qualified contractor.

PORTABLE UNITS - One piece or split systems. One piece unit has flexible duct to disperse hot air. The split system has an outdoor condenser. Portables are spot coolers only and are not designed to cover large areas.

Q: How about Air Purification?

Depending on the model, the Midea systems use either Plasma or Bio Filtration which absorb and decompose harmful bacteria, allergens, odours, dust and toxins for cleaner, healthier air. Contamination Control Laboratories conducted laboratory tested against Australian Standard 1807.8 on Midea split system air conditioners. As a result Midea split system air filtration system has been found to reduce specific air-borne particles and allergens by over 90%*. (Click through the link at the bottom of the page for test results.)

Q: Service and Maintenance?

All Midea air conditioners have a 5 year domestic warranty on manufacturing faults only; maintenance and user faults are not covered. Midea air conditioners feature Anti–Corrosion Hydrophilic Aluminium [Gold] Fins to extend the heat exchange performance of the outdoor unit, particularly where the unit is exposed to salt air or harsh conditions. (Any unit installed within 400 meters of salt water should also have a anti corrosion coating applied to the metal framework of the unit) Depending on the environment, it’s recommended the filters be cleaned every 2 weeks or at least once a month. In addition, a professional tradesperson should clean the unit at least once a year; this should be done before summer, as there will be long delays during the summer period.

Q: What are the installation requirements?

Allowance must be made for drainage from indoor unit on cooling mode and outdoor unit on heating mode. Positioning of the indoor unit is important and should not inhibit the flow of air from the unit. Where possible the unit should be placed centrally on a wall directing the airflow to the centre of the room. Outdoor unit must be positioned in a well-ventilated area on a solid footing and must be easily accessible for servicing purposes. Correct installation is vital to ensure the performance of the unit. As installation faults may void manufacturer warranties, only qualified air conditioning installers should carry out this work.

Q: How about Insulation?

When insulation is installed significant savings can be made on the running costs of air conditioning and a lower wattage unit could be installed, ie. Saving on the purchase cost.

Q: What are some of the factors to consider when buying and installing split air conditioners as well as window mount units?

Make sure the unit you purchase is correctly sized allowing the unit to cycle off when the correct temperature is reached. This allows for the compressor to switch on and off as required rather than running continuously.

Set your thermostat so that you feel comfortable rather than cold. Most of us feel comfortable at between 24 and 26 degrees in summer. Remember that in summer you will be dressed in summer attire.

Consider insulating the ceiling so that you may be able to use a smaller capacity unit.

Make sure the unit is securely mounted to avoid unnecessary vibration. Mounting through the wall will generally give a more secure install than through glass.

Maintain the filters of your air conditioner on a regular basis and in the case of split systems, have your unit serviced by a qualified tradesperson at least every two years depending on the environment the unit is installed in, some units require a professional service once a year.

Q: What are some of the factors to consider when locating your outdoor unit?

Is the unit going to be sitting on a concrete path or in a garden? Concrete paths are a highly reflective surface and will allow sound to travel further. A condensing unit mounted close to an adjacent wall will allow sound to be reflected off multiple surfaces making the sound louder.

Be sure to have maximum clearances around the outdoor unit, so there is no chance of the hot air from the outdoor being recirculated back into the outdoor unit especially if there is a wall directly opposite the unit. As this can cause the unit to over heat and fail especially on hot days.

Is the condensing unit going to be located under a carport or roofed entertainment area? These areas are more reflective of sound.

Is the condensing unit mounted on brackets on a wall? Make sure the unit is well isolated from the wall so as to avoid unnecessary vibration.

Is the fence between you and your neighbour's house a solid fence or a paling fence with gaps? A solid fence will not allow as much sound through.

Q: General Information of Interest

Horsepower is a measure of the rating of a compressor and does not relate to the cooling capacity of an air conditioner. Use watts or B.T.U.

Placing the outdoor unit in direct sunlight makes the outdoor unit work harder.

In cooling mode remember that the method of sizing most commonly used is designed around a maximum differential of around 10 degrees.

Most of us feel comfortable at between 24 degrees and 26 degrees and at a humidity level of 60% to 75% in summer and 55% to 70% in winter.

Over sizing is just as bad as under sizing as the unit may cycle off before the appropriate amount of dehumidification has occurred.

Installation is important. If a unit fails due to a problem with the installation (faulty flare connections etc.) it will not be covered under the warranty.

Location of the outdoor unit must be easily accessible.

Technical Terms / Acronyms

Star Rating

The Star Rating system assigns a number of stars to each air conditioner and this is displayed on the energy label. It gives an indication of how energy efficient an appliance is compared to other similar appliances. Currently, the range of stars is between a minimum of one and a maximum of six, shown in half star intervals.

MEPS

The Minimum Energy Performance Standards program is mandatory by government legislation for air conditioning equipment sold in Australia.

TESAW

TESAW is an award system created by government to recognize the most efficient star rated products on the market. It helps consumers quickly identify the most efficient products available. The government updates the award every year and the scheme replaces the previous Galaxy Award system.

Capacity Output

The measure of cooling or heating performance of an air conditioner usually specified in kilowatts although some product brochures still quote B.T.Us. The heating capacity of a reverse cycle air conditioner is the heat that can be put into a room. Likewise, the cooling capacity of an air conditioner is the heat that can be removed from a room.

EER

The measure of energy efficiency for cooling is the Energy Efficiency Ratio (E.E.R) and for heating is the Coefficient of Performance (C.O.P). The E.E.R and C.O.P are defined as the capacity output divided by the power input. The efficiency of the air conditioner depends on the components used, their design and how well these are matched.

COP

The measure of energy efficiency for heating is the Coefficient of Performance (C.O.P). Similar to E.E.R above but relating to heating performance. Heating performance of an air conditioner is one of the most efficient of all forms of heating as you get more heating capacity out compared to the power used.

DSP

Digital Signal Processing chip uses algorithms that require a large number of mathematical operations to be performed quickly on a set of data. Texas Instruments is widely considered the market leader in general-purpose DSPs.

R410a gas

Touted as the refrigerant gas of the future, R410a is the current preferred substitute for R22 gas. It has a higher thermal volumetric cooling capacity and thus better thermal exchange properties. The result is better system efficiency. R410a exhibits better environmental credentials than many other refrigerant gases.

R22 gas

R22 was the most commonly used refrigerant gas in residential and light commercial air conditioners, refrigerators and freezers until concerns about depletion of the ozone layer arose in the 1980s.Correct handling and reclaim procedures by installers and service technicians ensure that R22 can still be used in Australia.