It's recommended to schedule HVAC maintenance at least once a year for heating systems and once a year for cooling systems, ideally before the start of each season, to ensure optimal performance.

The type of air filter you should use depends on your specific HVAC system. It's essential to check the manufacturer's recommendations. Generally, high-efficiency filters (MERV ratings of 8-13) are effective for capturing allergens.

To improve efficiency, consider regular maintenance, using programmable thermostats, sealing ductwork, replacing old filters, and upgrading to energy-efficient models compliant with current standards.

Common signs include strange noises, inconsistent temperatures, increased energy bills, frequent cycling on and off, and unusual odors. If you notice any of these, it’s best to contact a professional HVAC technician for an evaluation.