Residential and commercial air conditioning systems use pressurized refrigerant to remove excess heat and humidity. The refrigerant passes through a network of coils and valves that allow the coolant to absorb and release heat as it changes between its gas and liquid forms. Primary components include the evaporator and condenser coils, compressor, expansion valve, and fans.

As a rule of thumb, replacement is recommended when repairs would exceed half the cost of a new system. Age, efficiency, and reliability are also deciding factors. Replacement is typically the best option for HVAC systems that are more than 10 years old and have problems with frequent breakdowns, decreased output, increased runtimes, excessive noise, or rising energy use. Alternatively, homeowners can multiply the age of the system by the estimated cost of repairs. If the amount exceeds $5,000, replacement is typically the best solution.

Compressor malfunctions are typically caused by faulty electrical connections, defective capacitors, and improper refrigerant levels that affect the system's operating pressure. Before calling a professional, homeowners can replace the air filter, double-check the thermostat settings, and hose off the outdoor unit to rule out minor maintenance-related problems. If these steps don't resolve the issue, the compressor may need to be replaced. Unfortunately, compressors aren't just one of the most critical components of the air conditioning system, they're also one of the most expensive. If the unit can't be repaired, a licensed HVAC contractor can determine whether a partial or full replacement is the best option.

Air ducts are responsible for a large portion of HVAC-related energy losses. According to the U.S. Environmental Protection Agency’s Energy Star program, 30% of heated and cooled air escapes from the ducts before it reaches its final destination. Some of the most common warning signs include hot and cold spots, odors, and low or no airflow. Loose ducts can be reconnected, and small cracks can be sealed with metallic foil tape. If the ducts are damaged, contaminated, or collapsed, it is usually time to call a professional. Trained AC technicians can also determine if the supply and return ducts are properly sized.

Homeowners’ insurance covers the cost of AC breakdowns caused by fire, lightning strikes, vandalism, or theft. To qualify for coverage, the homeowner must notify the insurance carrier of the loss and provide a report from a licensed contractor. Then, an insurance adjuster will evaluate the claim. Unfortunately, insurance coverage may only pay a limited amount, especially if the homeowner has a high-deductible policy.

The average AC system has an expected lifespan of 14 years. Longevity can vary substantially depending on the unit's maintenance history and building-related factors that determine how often the system runs. Homeowners can extend the life of their HVAC equipment by scheduling annual maintenance, replacing filters monthly, and using recommended thermostat settings.

Preventive AC maintenance is the key to increased longevity. Here are a few of the most beneficial tasks that homeowners can perform themselves.<ul><li>Replacing air filters monthly</li><li>Using recommended thermostat settings</li><li>Keeping shades or blinds closed during the summer</li><li>Hosing off the outdoor coils to remove pollen and dirt</li><li>Monitoring utility bills for changes in consumption</li><li>Scheduling professional tune-ups every spring</li></ul>If problems arise, it's wise to contact a professional as soon as possible to avoid more extensive repairs. Responding quickly is the best way to prevent sudden breakdowns that may require a more expensive emergency service call.