It is essential to select a split AC of the right size. Too small unit cannot cool the room and the cooling temperature will not be attained as expected. Opting for an oversize unit will cool the room quickly, but the on & off cycle will get affected. You simply need to pay more on utility bills.
How to measure a room?
The room has length 4m and width 3m
- Multiply length by width
4m x 3m = 12m
12m x 140 W = 1680 W
You need minimum 1680 W to cool the space. Therefore 2.0 KW is ideal and anything less will be inefficient in cooling the space.
Other aspects to consider with the size
- Ceiling height increase BTU
- Sunlight add to BTU
- Shade decrease BTU
- Number of occupants add BTU if room is used by more than 2 persons regularly
- For kitchen area – amplify BTU level, significantly
Let’s understand the cooling effect of four different sizes of Carrier AC unit in an average sized home.
Unit size 5 Kw
Air conditioner circulates air in given space. It not blows air in a single direction. If you think of installing 5 Kw to cool the kitchen, dining, living room and lobby area of an average home then it is not the proper size. The area is large and it will struggle to keep area cool. Eventually, the lifespan will decrease because it works hard.
Unit size 6 Kw
A 6 Kw is capable to cool the whole area efficiently. On hottest day the machine will keep the temperature even without working overtime. However, the hallway will allow plenty of air escape making use of more power to maintain desired temperature.
Unit size 7 Kw
6 Kw size can handle cooling load efficiently but energy consumption needs to be considered, if you wish future expansion like cooling the far bedroom. Actually, you will witness that the far rooms don’t get appropriate coolness.
It is because the thermostat mounted on the head controls cooling behaviour. When the main rooms kitchen, dining room, living space reaches optimum temperature the unit ramps down. The cooling does not reach the far rooms, so let’s increase a size more.
Unit size 8 Kw
Power consumption and air flow range difference between 7 and 8 is substantial. The 8 Kw is very potent machine giving 1000 W more cooling power but still the far rooms don’t cool appropriately.
Actually, 8 Kw is suitable for large open space areas, only. Temperature under 18 is not comfortable, so installing unit size 8 Kw is not helpful, it will unnecessarily increase your utility bills. Therefore, the above option 7 Kw is perfect. For your bedrooms install a separate right size unit.