HVAC and air filters: staying cool through a Valley summer

To stay cool through a Central Valley summer, change your HVAC air filter every 30 to 45 days during peak heat instead of the usual 90, because a clogged filter chokes airflow right when your system runs hardest. Pair that with an annual check of the crossover duct under your home, and your AC can keep up even on a 105-degree Fresno afternoon.

Your filter lives in the return-air grille, usually a large vent in a hallway, wall, or ceiling. When it loads up with our Valley dust and pollen, the blower strains, cooling drops, and energy bills climb. During spring and fall a fresh filter every 60 to 90 days is fine, but summer in Fresno is a different animal.

The manufactured-home difference: the crossover duct

Double-wide and multi-section homes join their two halves with a crossover duct, usually a 14 or 16-inch insulated flexible duct running under the floor between sections. If it gets crushed, the clamps loosen, or the insulation tears, one side of the home stays warm while your AC runs nonstop. Inspect it once a year.

• Confirm the crossover duct is connected at both ends with bands and is not resting on the ground.
• Look for crushed sections, torn vapor wrap, or insulation that has fallen away.
• Feel along the belly wrap for escaping cold air, which signals a duct leak wasting your cooling.
• Seal small leaks with metalized tape, not standard cloth duct tape, which dries out and fails.

If your home struggles to cool even with a fresh filter and a sound crossover duct, have a technician check the refrigerant charge and the condenser. In our climate, a system that cannot hold temperature on a hot day is overdue for service, not just a hot afternoon.