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Maintenance

Air Filter Replacement Guide for California Homes

Replacing your air filter is the simplest, cheapest thing you can do to protect your HVAC system and maintain good indoor air quality. It takes five minutes and costs a few dollars. Yet it's one of the most commonly neglected maintenance tasks — and one of the most common causes of HVAC problems.

How often to replace the filter. The standard recommendation is every 1 to 3 months, but the right interval depends on your home. Replace more frequently if you have pets, multiple occupants, someone with allergies or asthma, or if you live in a dusty area. During peak cooling season in the Central Valley, monthly checks are a good habit.

How to choose the right filter. Filters are rated by MERV (Minimum Efficiency Reporting Value). Higher MERV ratings capture smaller particles but also restrict airflow more. For most homes, a MERV 8 to 11 filter strikes the right balance between filtration and airflow. Very high MERV filters (13+) can restrict airflow enough to strain the system unless the equipment is designed for them.

What happens when you don't change the filter. A clogged filter restricts airflow through the system. This forces the blower to work harder, increases energy consumption, reduces cooling and heating capacity, and can cause the evaporator coil to freeze. Over time, restricted airflow can damage the compressor — the most expensive component in the system.

How to change the filter. Locate the filter slot — usually at the air handler or in a return air grille. Note the size printed on the existing filter. Turn the system off, remove the old filter, and insert the new one with the airflow arrow pointing toward the unit. Turn the system back on.

Set a reminder. The easiest way to stay on schedule is to set a recurring reminder on your phone. Some homeowners buy filters in bulk and keep them near the air handler so the task is easy to complete.

West Coast Air Conditioning is happy to check and replace your filter during any service visit. Call (209) 598-8889 to schedule maintenance.

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