Your heating and cooling system is one of the most expensive things in your home, and a little routine care keeps it running efficiently and prevents the breakdowns that always seem to strike on the hottest or coldest day. Here is a simple seasonal checklist any homeowner can follow.

Every month or two - Replace or clean the air filter. This is the single most important task. A clean filter improves airflow, lowers bills, and protects the system. - Glance at vents and registers to make sure furniture or rugs are not blocking airflow.

In spring, before cooling season - Clear leaves and debris from around the outdoor unit, leaving at least two feet of clearance. - Gently rinse the outdoor coil with a hose after shutting off power. - Test the system by running it before the first heat wave, so you discover problems early. - Check that the condensate drain line is clear to prevent water backups.

In fall, before heating season - Replace the filter again heading into winter. - Run the heat briefly to catch issues before you truly need it; a brief burning smell from dust is normal, but anything persistent is not. - Test your carbon monoxide detectors and replace batteries.

Year-round habits - Keep the area around indoor units clean and unobstructed. - Pay attention to new noises, smells, or weak airflow, which are early warning signs.

Schedule a professional tune-up Once a year, have a licensed pro inspect refrigerant levels, electrical connections, and the burner or compressor. A professional tune-up catches small problems before they become expensive emergencies and keeps your warranty valid.