Your first instinct when buying a commercial HVAC unit might be to buy the largest capacity. It would seem that a larger the unit will do better at cooling your home. This is not always the case. Size makes a big difference on how efficiently your home is cooled and buying one that doesn’t fit the square footage of a home is one of the worst mistakes you can make. Large air conditioners are meant for larger homes and businesses. When a unit is designed to cool a large area and your home is smaller than that area, money is simply wasted.
A commercial HVAC unit that is too big can actually cause more problems for you than one that is too small. Your house will be cooled quicker with a larger unit but will not dehumidify the air. Dehumidifying is a process units are designed to perform along with cooling. Moisture remains in the air when cooling happens too quickly and can make it very uncomfortable. A unit that is too small will not be able to keep up resulting in a still warm home. It will dehumidify the air as it cools the air. Smaller units use less energy even when running constantly. A larger one will naturally cost more even if it runs less.
Of course the best thing to do is buy an air unit that is meant for your home. An air conditioning service can help you determine what size will do the most good. They can run tests that determine what capacities should be used and will also be able to give advice when buying the unit. An air conditioning service has knowledge of each type of unit and can tell you which ones are worth the cost. A central air unit is something that should last and choosing the right size will prevent having to make changes or replace the unit early.