Central air
What it is
A central air conditioner circulates cool air through a home using a system of ducts and registers.
Split system means any central air conditioner in which one or more of the major assemblies are separate from the others.
Have central air handling systems, including furnaces, flues and chimneys, inspected annually and properly repair cracks or damaged parts.
For some, it may be helpful to think of a ducted ASHP as a central air conditioner that also works in reverse to provide whole-house space heating in winter.
U.S. Department of Energy · Code of Federal Regulations · U.S. EPA · ENERGY STAR
Its parts
- Condenser
- Condensing unit means a component of a “central air conditioner” which is designed to remove heat absorbed by the refrigerant and to transfer it to the outside environment, and which consists of an outdoor coil, compressor(s), and air moving device.
- Disconnect switch
- Electrical Measurements – Taken at electrical disconnect while component is in operation
- Line set
- Condensing units are typically provided with sufficient charge to accommodate 15–25 ft of refrigerant tubing. The line sets and indoor coil must be purged with nitrogen and evacuated to 240 microns of mercury and held for 10 minutes prior to opening service valves.
- Expansion valve
- If overfeeding of the expansion valve causes intermittent flooding of liquid into the suction line, the compressor may be damaged.
- Liquid refrigerant enters the expansion valve, is reduced in pressure and temperature at the valve port, and enters the evaporator at point A as a mixture of saturated liquid and vapor.
- Metering device
- The indoor unit includes an evaporator coil and a metering device that are located in the air handler unit, which also contains a blower fan that blows the conditioned air into the supply ducts for distribution throughout the house and receives stale house air from the return ducts. The outside unit contains the condenser and the compressor.
- Evaporator coil
- Evaporator coil means a component of a central air conditioner that is designed to absorb heat from an enclosed space and transfer the heat to a refrigerant.
- Air handler
- Short duct runs can bring fresh air to the supply plenum and exhaust can be drawn from the return plenum. Research has found that this strategy does not work well. When the central air handler fan is not running, the outdoor air follows the path of least resistance.
- Condensate drain
- Check and inspect the condensate drain in your central air conditioner, furnace and/or heat pump (when in cooling mode). A plugged drain can cause water damage in the house and affect indoor humidity levels.
Related pages
- Glossary: Central air
Its entry, and the guide's pages that use it.
- Central air conditioning
The parts of a split system, what is normal and the signs of trouble
Sources
- U.S. Department of Energy. Energy Saver 101: Home Cooling.
- Code of Federal Regulations. 16 CFR Part 305 Energy Labeling Rule.
- U.S. EPA. Sources of Combustion Products.
- ENERGY STAR. U.S. EPA Consumer Messaging Guide for ENERGY STAR Certified Air Source Heat Pumps.
- U.S. Department of Energy. HVAC Programmable Thermostats.
- ASHRAE. ASHRAE Handbook—Compressors.
- ENERGY STAR. HVAC System Quality Installation Rater Checklist Guidebook.
- U.S. Department of Energy. Measure Guideline: Air Conditioner Diagnostics, Maintenance, and Replacement (DOE Building America).
- ASHRAE. ASHRAE Handbook—Refrigerant Control Devices.
- U.S. Department of Energy. Traditional Split Heat Pumps.
- U.S. Department of Energy. Whole House Ventilation Strategies for Existing Homes.
- ENERGY STAR. Maintenance Checklist.