The kW you need comes from a room-by-room load calc, not the floor area or the price list. Why an oversized unit costs more to run than a right-sized one, what a load calc actually measures, and the question that separates a real installer from a "she'll be right" quote.
Sizing is the single most important decision in an air conditioning install, and the one most often guessed. The number you want is in kilowatts of cooling (and heating) capacity, and it does not come from the floor area or the price list. It comes from a heat-load calculation.
Get it wrong in either direction and you pay for it. Too small and the system runs flat out on the hot days it was bought for, and never quite gets there. Too big, which is the more common mistake, and it short-cycles: it blasts the air cold, hits the thermostat, and shuts off before it has pulled the humidity out of the room. You end up cool but clammy, with a compressor switching on and off all day and a power bill to match.
A proper sizing looks at the things that decide how much heat a room gains, room by room:
On the coast there is one more: a room open to the sea breeze behaves differently to a sealed, glassed-in living space. The point is that none of this is visible in a floor plan, which is why a quote built off the floor plan is a guess wearing a number.
A working installer measures the rooms and runs the calc before naming a kW. The one-number text that lands before anyone has seen your place is the quote to be careful with.
It feels safe to go bigger. It is not. An oversized system reaches temperature too quickly, so it spends its life in short bursts rather than the long, steady run an inverter is designed for. That means more wear, worse humidity control, and higher running costs than a smaller unit that is matched to the room. Right-sizing is not about saving on the box; it is about the next ten years of bills and comfort.
Ask this, exactly
“Can you run a room-by-room load calc and show me how you arrived at the kW, before you quote a model?”
A working installer will measure and calculate. If the size arrives before anyone has seen the rooms, you are being sold a guess.
Every Saltline quote starts with a site visit and a room-by-room load calc, and the calc is the first line on the quote. We name the model and the capacity it points to, so you can see why the size is the size. It is the difference between a system that runs quietly in the background for a decade and one you are calling someone about every summer.
Saltline Air & Refrigeration