HVAC Filter Change Schedule: A Simple Home Rule

The most expensive part of your home maintenance isn't always a broken part—it's often a dirty $10 filter. An HVAC filter that stays too long restricts airflow, forces your system to work harder, and drives up energy bills. Worse, it can freeze up your AC coils or overheat your furnace.

1. The "Standard" Schedule

How often should you change it? Manufacturers often say "every 3 months," but that is a generic average.

• Vacation Home / Single Occupant: Every 3–4 months.
• Average Family (No Pets): Every 2–3 months.
• Family + 1 Pet: Every 2 months.
• Family + Multiple Pets / Allergies: Every 30–45 days.

2. The "Visual Check" Method

Calendars are great, but your eyes are better. Check the filter monthly.

• White: Good. Leave it.
• Light Gray: It's working. Plan to buy a replacement soon.
• Dark Gray / Clogged: Change it immediately. Air is struggling to pass through.

3. MERV Ratings Explained

Don't just buy the highest number. High filtration can choke older systems.

• MERV 1-4: Fiberglass. Catches birds and bowling balls. Useless for dust. (Avoid).
• MERV 5-8: Pleated. Catches dust, pollen, and mites. The standard for most homes.
• MERV 11-13: High efficiency. Catches smoke and bacteria. Great for allergies, but check your manual to ensure your blower motor can handle the resistance.

4. Seasonal Factors

Filters get dirty when the system runs.

• Summer/Winter: Your system runs daily. Check monthly.
• Spring/Fall: You might use windows more. The filter might last 3-4 months.

5. Why It Matters

A dirty filter creates a pressure drop. Your system has to run longer to reach the same temperature. This can increase your energy bill by 5–15%. Changing a $10 filter can save you $50 in electricity.

Summary

Set a recurring reminder on your phone for the 1st of every month to "Check Filter". It takes 30 seconds and saves you money.