The air handler is a device contained in a sheet metal box that is comprised of a blower, a filter, dampers and heating or cooling parts that help to circulate the conditioned air throughout the home. The air handler determines how much air is pushed through the system, so the correct size and type of unit can have a significant effect on the comfort of the indoor environment.
Air handlers may be small or large units depending on the requirements of the system. Large buildings may have their air handlers on the rooftop instead of in attic areas. Heat pump-type HVAC units generally have the air handler as a separate unit, often in the attic area. Air handlers are also used for special work situations where the air quality can have a bearing on worker safety or productivity.
Local codes may specify requirements for air handlers in attic areas, such as keeping the unit within 6 feet of the access door, installation of a light fixture near the air handler or provision for an alarm to alert the owner of problems with condensation, according to TaylorCountyGov.com. Some parts of the country discourage the use of air handlers in attic areas because the extreme heat in attics cause them to operate inefficiently. In these cases, placement in the garage is often preferred. The size of the air handler unit is important to the efficient function of the system. Air-conditioning systems are carefully matched with air handlers to provide the best airflow for the square footage of your home.
Installation in the attic area is not always a good location for the air handler. Attics can often have very high temperatures that make the unit work harder and use more energy to function. Attics may have small access points that make installation unworkable. In addition, attics are often tight areas that make repair of the unit difficult for technicians, according to Accurate Home Inspections Services.