When it comes to keeping your home comfortable and energy-efficient, few maintenance tasks are as simple—or as important—as replacing air filters. A clean filter protects your HVAC system, improves air quality, and keeps your furnace running efficiently through the cold weather months.
But one of the most common questions our technicians at Comfort Zone Services hear from homeowners is: “How often should I change my furnace filter?”
Let’s break down the answer, plus everything else you should know about furnace filters, from MERV ratings to recyclability.
How Often to Change Your Furnace Filter
In general, most homeowners should change their furnace filter every 60–90 days. However, the exact schedule for how often to change your furnace filter depends on several factors, including the type of filter you use, your home’s air quality, and whether you have pets or allergies.
Here’s a quick guide:
- Fiberglass filters: Replace about every 30 days. These are inexpensive but less efficient.
- Pleated filters (MERV 8–12): Replace every 60–90 days. Pleated filters capture smaller airborne particles.
- HEPA filters or charcoal filters: Replace about once a year, depending on usage and manufacturer recommendations. Some HEPA filters are even washable.
Pro tip: If you’re unsure, check your filter monthly. Hold it up to a light; if you can’t see through it, it’s time to change it.
Why Changing Your Furnace Filter Matters
Your furnace filter does more than trap dust. It also protects your entire HVAC system. When a filter becomes clogged with dirt, pet hair, and debris, airflow is restricted. That means your furnace has to work harder, so it uses more energy and will likely wear out more quickly.
Neglecting filter changes can lead to:
- Higher energy bills
- Uneven heating or weak airflow
- Frequent furnace repairs
- Poor indoor air quality
How to Change a Furnace Filter
Changing a furnace filter is one of the easiest DIY home maintenance tasks. Here’s how to do it:
- Turn off your furnace. Safety first!
- Locate the filter. It’s usually found in the return air vent or inside the furnace cabinet near the blower.
- Remove the old filter. Remove the blower cabinet door or mounted access panel and take out the old filter. Note the filter’s size (printed on the frame).
- Check the airflow direction. Every filter has an arrow showing which way the air should flow. The arrow should always point toward the furnace (the direction the air moves).
- Insert the new filter. Make sure it fits snugly with the airflow arrow in the correct direction.
- Turn the furnace back on.
If you’re wondering, “Which way do filters go in the furnace?” — remember: arrow toward the furnace.
How Often to Replace Furnace Filters Based on Lifestyle
Aside from the type of furnace filter, your ideal replacement schedule also depends on how and where you live:
- Homes with pets: Every 30–60 days. Pet dander and fur clog filters faster.
- Allergy sufferers: Every 30–45 days. Clean filters reduce airborne allergens.
- Large families or heavy HVAC use: Every 30–60 days. More people = more dust and debris.
- Vacation or single-occupant homes: Every 90–120 days. Less frequent use means slower buildup.
- Urban areas or near construction: Every 30–60 days. Outdoor pollutants can quickly dirty filters.
You may also need to change filters more often during high-use seasons (i.e., winter for heating and summer for cooling).
Understanding Furnace Filter Types and MERV Ratings
The MERV rating (Minimum Efficiency Reporting Value) tells you how well a filter captures airborne particles. The higher the MERV rating, the finer the filtration.
Here’s a breakdown:
- MERV 1–4: Basic protection against large dust and lint.
- MERV 5–8: Captures dust, mold spores, pet dander, and pollen, making it a good choice for most homes and light commercial use.
- MERV 9–12: Removes lead dust, pet dander, and finer particles like auto emissions and bacteria.
- MERV 13–16: High-efficiency filters that trap dust, allergens, smoke, and even viruses. These are typically used in hospitals and labs.
- HEPA (MERV 17+): Removes up to 99.97% of particles. It’s ideal for allergy-sensitive households and used in operating rooms.
Keep in mind that not all furnaces are designed for high-MERV filters. Using one that’s too restrictive can reduce airflow and strain your system. When in doubt, ask one of our HVAC experts to recommend the right filter for your equipment.
Are Furnace Filters Recyclable?
In most cases, furnace filters are not recyclable because they contain a mix of materials like fiberglass, wire mesh, and synthetic fibers. However, some eco-friendly or reusable filters can be washed and reused, which helps to reduce waste.
If you’re looking for a greener option, consider a washable electrostatic filter or a high-efficiency reusable filter. Just be sure to follow cleaning instructions carefully to maintain performance.
When to Call the Professionals
While changing your furnace filter is an easy DIY job, sometimes, poor airflow or dust buildup can point to larger issues like dirty ducts, blocked vents, or an overworked system.
If your furnace still isn’t performing well after replacing the filter, it may be time to schedule a professional HVAC inspection. Our team at Comfort Zone Services offers thorough inspections, maintenance plans, and tune-ups to keep your system running smoothly through every season.
How Often to Change Your Furnace Filter: The Bottom Line
Knowing how often to change your furnace filter and which type of filter to use will protect your investment. For most people, every 60 to 90 days is the magic number.
Whether you’re a new homeowner trying to learn the basics or you’ve owned your home for years, making this small maintenance habit part of your routine will:
- Improve air quality
- Extend the life of your furnace
- Lower your monthly energy bills
Need help finding the right filter or want expert advice on your HVAC system?
Contact Comfort Zone Services today! We’ve been proudly serving the London, Ontario area with trusted heating and cooling care for over 25 years..