Filters should generally be replaced every 1 to 3 months, depending on filter type, household pets, and overall usage.

This is often caused by a dirty air filter blocking airflow, a tripped circuit breaker, low refrigerant levels, or a malfunctioning thermostat.

Professionals recommend scheduling a tune-up twice a year (once in the spring for AC, once in the fall for heating) to maintain efficiency and validate manufacturer warranties.

High bills can be caused by dirty coils, leaky ductwork, restricted airflow from old filters, or an aging, inefficient system.

As a general rule of thumb, if the unit is over 10–15 years old, or if the cost of the repair multiplied by the age of the unit exceeds the price of a replacement, an upgrade is usually more cost-effective.

This is typically a zoning issue, caused by blocked vents, leaky ducts, poor insulation, or an improperly sized system.