Murphy's Law says it is at this precise moment your air conditioning will fail when the water pump throws a bearing.

What could you have done about it? Well a simple pre-summer service would most likely have picked up the issue early.

Having your air conditioner serviced annually, before the warm weather kicks in, should be on the must-do list for any homeowner (or renter).

George Weston has decades of experience as a refrigeration mechanic having operated a refrigeration and air conditioning business with is brother for over 40 years.

His take on servicing is quite simple - you have a service done to prevent a minor problem becoming a major problem.

"It is not life and death, but very much an inconvenience if you lose your air conditioning," George said.

"People work better and function better when they are cooled.

"And nothing breaks down between nine and five, Monday to Friday. It will always break down at an inconvenient time.

"You've always got to be proactive, not reactive."

There can be mechanical and natural reasons for an air conditioning system to break down, from a loose screw or corroded wire, to an errant gecko in the electrics or wasps' nest on fan blades in a system that has been dormant for six months.

"It is pertinent to get the machine checked out because you might have a bolt ready to snap or a wire just coming loose," George said.

"If you don't get it checked out, when it is five, six or seven days running flat out, that's when it will show up the symptoms."

It is important to arrange to have your cooling system serviced early because the summer months are the busiest for air conditioning companies.

"Summer arrives and it becomes very busy for us; it really hits about a week after the hot weather starts," George said.

"If you don't get in early, when summer does strike the industry becomes very busy. If you get in early you'll be able to get someone to do the servicing."

Evaporative: Outside air passes through a wet filter to cool and humidify the air, which is then blown through the house.

Air conditioning: Refrigerated cooling of the air. Also maintains humidity.

Air conditioners come in several types -

Reverse-cycle: Can heat as well as cool, providing year-round climate control.

Portable units: Good for cooling a small room or individual. Can be moved as needed.

Window/wall units: Sits both inside and outside, poking through a window or wall. Cheap to purchase, expensive to run.

Split system: A system with the compressor unit outside the house and the air outlet inside.

Ducted: Air is pumped through ducts into different parts of the home. The fan coil is mounted in the ceiling, the condensing unit is outside the home (split system).

Zoning: A way for a ducted unit to blow air into designated rooms (zones).

Inverter: Uses electricity more efficiently to deliver a fixed amount of cooling and maintain a desired temperature instead of stopping and starting.