How Does Radiant Heat Affect My AC?

Function

• Air conditioners have two functions in climates where either the heat or humidity levels create uncomfortable conditions. Air conditioners cool air and remove humidity at the same time. Air conditioners use different types of gases and their compressors use pressure to change the gas into a liquid, which cools it. Their fans blow over the cooled coils and as the air passes over the coils, water condenses and additional fans blow the air into the space in need of cooling.

Significance

• Air conditioners have created livable environments in hot places with significant radiant heat like Miami, Phoenix and Las Vegas. Before the advent of air conditioning, these cities were small compared to their current sizes. It may be that air conditioning brought companies and people into these cities for their once low cost of living and mild winter climates.

Conservation

• People can cut back on the amount of electricity that an air conditioner uses by blocking the sun that hits a building, home or car by shading it with landscaping materials like vines or deciduous trees. Effective wall and roof insulation helps stop radiant heat, as do window coverings like shade screens or thermal drapes. Keeping a car parked in the shade, under a carport or in a garage, reduces the amount of time the compressor runs, extending its life.

Placement

• Radiant heat from the sun can cause an air conditioner to run less efficiently. Sun striking the surface of the condenser or window-mounted air conditioner heats the coils inside the units, warming the coolant. Some people build shaded shelters for their condensing units that can reduce the length of time the unit must run to cool. These structures need to have at least 12-inches between the condenser and the structure walls with at least 30-inches of air space above the unit. Planting trees or shrubs can also shield the unit from the heat.