What is BTU?

BTU is short for British Thermal Unit, and is a basic measure of thermal (heat) energy. One BTU is the amount of energy needed to heat one pound of water one degree Fahrenheit, measured at its heaviest point.

Most heating and cooling systems produce thousands of BTUs, almost rendering themeasurement of one BTU pointless. Air conditioning units are therefore measured by their BTU’s. Larger and more expensive systems should provide significantly higher BTUs than smaller ones. When deciding between similarly priced units,compare the BTU’s for a better gauge of performance.

How do I know the size is right?

This is probably one question of extreme importance and crucial to having a solution that works!

A system that is too large will cool or heat your house quickly, but you may not feel comfortable. That’s because it will satisfy the thermostat before it can adequately remove sufficient moisture from the air during the cooling mode, leaving you feeling sticky and humid. This could even lead to moisture and mold problems. And, the stress of short-cycling (too many starts and stops) will shorten the life of your equipment and increase your heating and cooling bills.

On the other hand, a system that is too small just cannot get the job done, especially in extreme weather conditions. The air conditioner will run constantly in the summer and the furnace will do the same in winter.

But a correctly sized system isn’t just based on the size of the structure. Many factors go into determining the size of the system. Including type of house and walls, type and size of windows, insulation, basement and attic conditions, house orientation, and so on. At Cool Air, we ensure that a consultant visits your home or office in order to ascertain the correct measurements and therefore suggest the appropriate unit.

The following is a recommendation of unit sizes vs room sizes:

Approximate Room Size: Suggested Aircon Size:
15 to 18 m²  9000 BTU
20 to 25 m² 12 000 BTU
30 to 35 m² 18 000 BTU
40 to 45 m²  24 000 BTU
55 to 60 m² 30 000 BTU


How does an air conditioner work?

Air conditioners and refrigerators work the same way. Instead of cooling just the small, insulated space inside of a refrigerator, an air conditioner cools a room, a whole house, or an entire business. However, there are different measures of energy (BTU) per unit and therefore the room size must be taken into consideration in the installation of the appropriate unit.

Air conditioners use chemicals that easily convert from a gas to a liquid and back again. This chemical is used to transfer heat from the air inside of a home to the outside air.

The machine has three main parts. They are a compressor, a condenser and an evaporator. The compressor and condenser are usually located on the outside air portion of the air conditioner. The evaporator is located on the inside the house, sometimes as part of a furnace. That’s the part that heats your house.

The working fluid arrives at the compressor as a cool, low-pressure gas. The compressor squeezes the fluid. This packs the molecule of the fluid closer together. The closer the molecules are together, the high its energy and its temperature.

The working fluid leaves the compressor as a hot, high pressure gas and flows into the condenser. If you looked at the air conditioner part outside of a house, look for the part that has metal fins all around. The fins act just like a radiator in a car and help the heat go away, or dissipate, more quickly.

When the working fluid leaves the condenser, its temperature is much cooler and it has changed from a gas to a liquid under high pressure. The liquid goes into the evaporator through a very tiny, narrow hole. On the other side, the liquid’s pressure drops. When it does it begins to evaporate into a gas.
As the liquid changes to gas and evaporates, it extracts heat from the air around it. The heat in the air is needed to separate the molecules of the fluid from a liquid to a gas. The evaporator also has metal fins to help in exchange the thermal energy with the surrounding air. By the time the working fluid leaves the evaporator, it is a cool, low pressure gas. It then returns to the compressor to begin its trip all over again. Connected to the evaporator is a fan that circulates the air inside the house to blow across the evaporator fins. Hot air is lighter than cold air, so the hot air in the room rises to the top of a room.

There is a vent there where air is sucked into the air conditioner and goes down ducts. The hot air is used to cool the gas in the evaporator. As the heat is removed from the air, the air is cooled. It is then blown into the house through other ducts usually at the floor level. This continues over and over and over until the room reaches the temperature you want the room cooled to. The thermostat senses that the temperature has reached the right setting and turns off the air conditioner. As the room warms up, the thermostat turns the air conditioner back on until the room reaches the temperature.

Which manufacturer or brand makes the best airconditoner?

Air conditioning is a matured technology so most of the popular brands work well. Many of them use parts made by the same manufacturers. So, the main considerations are the price, warranty, attractiveness, noise, etc. Some manufacturers offer a 3-5 year warranty on all parts while others offer only 1 year. Some units are unattractive and will not compliment your landscaping.
Whatever you decide, the most important consideration is the installer you use. You may buy the best system in the world but if it is not properly installed, you will actually be buying nothing but a big headache for years to come. For your protection, make sure you use a specialised contractor such as Cool Air so that our expertise becomes your ease.

How long does it take to install?

This is dependant on the type of unit you choose and the area in which it is installed. In most circumstances, a single or twin split application can be installed in one day, with minimum disruption.

How often should I have my unit serviced?

Heating and Air Conditioning equipment should be serviced at least once a year. The best scenario is to have the heating system checked in Autumn and the air conditioning checked in Spring to ensure durability, longevity and efficiency of use.

Why should I have my unit serviced?

Annual servicing includes cleaning the system, checking for any problems or potential problems and adjusting for Peak efficiency. The benefits include:

• Increased dependability.
• Find potential problems and fix them quickly.
• Provide maximum efficiency which lowers energy costs.
• Prolongs the life-span of the equipment.
• Maintains safe and healthy operation.
• Can help to protect the environment.
• Drastically reduces the chance of a break-down.

Many Service Plans also include extra benefits, including:

• Discounts on repairs.
• Discounts on purchases and future replacement.
• Priority Status for Scheduling.
• Increased warranty duration.

How can I save energy whilst using an air conditioner?

There are some simple things you can do to save energy when using an air conditioner:

• Install the air conditioner (or outdoor unit of a split system) on the shady side of the building (or shade the air conditioner itself); make sure the air flow around it isn’t obstructed.
• The temperature of a heated room in winter should be between 18-21°C while the temperature of a cooled room in summer should be about 23-26°C (remember the humidity indoors will be low, so it will feel cooler). The temperature should be checked after the air conditioner has been operating for 30 minutes. When a hot day is expected, turn on the air conditioner early rather than wait till the building becomes hot (it operates more efficiently when the outside air temperature is cooler).
• Keep windows and doors closed when using a refrigerative air conditioners (evaporative air conditioners require some air flow). Close curtains on hot summer days and cold winter nights. Outdoor shading of windows in summer is most effective. If the machine has adjustable louvres, adjust them towards the ceiling when cooling, and towards the floor when heating (as cool air falls, hot air rises). Follow the manufacturer’s instructions for filter cleaning.