Add 600 BTUs for every person beyond the first two.
Before shopping, you must calculate the required . A unit that is too small won't cool effectively, while one that is too large will cycle on and off too quickly, leaving the air damp and clammy.
If ceilings are over 8 feet, increase the BTU estimate by 10% . 2. Choose the Right Type of Unit
Increase capacity by 10% for very sunny rooms; reduce by 10% for heavily shaded ones.
Add 4,000 BTUs to account for heat from cooking appliances.
The best type for you often depends on whether you own or rent your home.
