Air Con. What size system should I get?

How do you choose the right size? For your air conditioning to work best, you need to have accurately calculated the size of the unit you require. Too small and the unit will need to run more often at maximum capacity drying out the air too much and will cost more in electricity. Uncomfortable for you and bad for your system as its lifespan will be reduced. Too large and your unit will run at shorter cycles more frequently leading the air retaining too much moisture making the room uncomfortably humid and excessive wear and tear.
To avoid either of these outcomes you must accurately calculate the required cooling or heating capacity of your new air conditioning system. Rated in kilowatts (kW) your requirements are dictated by the size of the rooms you have. A small area may need a 2.5kW system with a larger space or open-plan area requiring 6kW or larger.
What to be aware of
Be careful of relying on online calculators or installers that offer you only basic analysis; they may end up offering you a system that’s larger than you need. To accurately calculate the size of the air conditioning system you need you must consider not just the room size but how it’s used, the size and orientation of the windows, furnishings, if it has insulation (floor, ceiling and walls), external shade, local climate and what sort of shade and curtains it has.
To accurately determine what the best air conditioning solution is for your individual requirements, talk to a licenced air conditioning installer and have them assess your home and tailor a solution for you based on the above criteria. They should be only too happy to advise you accordingly and provide you with a solution that will be efficient and last for years.