• The climate of the area in which you live is a crucial factor. If you live in an extremely cold region you will require a unit of higher tonnage than is required otherwise.
• The size of the unit will also depend on factors such as size, shape, design, orientation, number of floors and other features of a house.
• Some contractors also take factors such as age of the construction, the materials with which the house has been constructed etc.
• The windows of house are a very important factor. They play a key role in heat loss and heat gain. The contactor should check the number, age, location, size, type, and orientation of your windows.
• Insulation is a pivotal factor that decides the efficiency of a HVAC fitted in your house. Some houses are strictly air-tight while others may have loop holes in the thermal envelop.
• The size of the air conditioner is based on presence of lights and other heat-generating appliances and their efficiency levels.
• The number of inmates living in the house is a deciding factor.
• If the walls of most rooms are directly exposed to sunlight, you may require a greater tonnage. The amount of sunlight that seeps into the house is a factor to be considered.
• If the house is surrounded by trees and shrubs and is well shaded, you will require a little lesser tonnage.