January 23, 2026

How Often Should You Change Your Furnace Filter?

Many homeowners don’t realize that one of the simplest ways to protect their heating system is also one of the most important: changing the furnace filter regularly. If you’ve ever wondered how often you should change your furnace filter, you’re not alone. It’s one of the most common questions our technicians hear at Applewood Plumbing Heating & Electric.

In most cases, you should change your furnace filter every 1 to 3 months, although there are some exceptions. Below, we’ll explain what factors affect your replacement schedule, and when it’s time to call a professional for furnace maintenance. 

Why Changing Your Furnace Filter Matters

Your furnace filter is designed to trap dust, pet dander, pollen, and other airborne particles before they circulate through your home. As the filter collects debris, airflow gradually gets more and more restricted. When airflow drops, your furnace has to work harder to heat your home, which increases wear on components like the blower motor and heat exchanger.

A dirty filter can also cause uneven heating, weak airflow, and frequent system cycling. Over time, this added strain can shorten the lifespan of your furnace and increase the risk of breakdowns during cold weather.

Regular filter changes help your furnace run efficiently, protect indoor air quality, and reduce unnecessary stress on the system.

How Often Should You Change Your Furnace Filter?

For most homes, the general rule is to change your furnace filter every 1 to 3 months. However, the exact timing depends on several factors, including filter type, household conditions, and how often your furnace runs.

Standard 1-Inch Filters

These are the most common filters found in residential systems. They typically need to be replaced every 30 to 60 days, especially during the heating season when the furnace runs frequently.

Pleated or High-Efficiency Filters

Thicker pleated filters can usually last up to 90 days, but they still need regular inspection. While they capture more particles, they can clog faster in dusty environments.

Homes With Pets

If you have dogs or cats, fur and dander will clog filters more quickly. In these homes, it’s best to replace the furnace filter every 30 to 45 days.

Homes With Allergies or Asthma

Households that prioritize air quality often benefit from more frequent changes—about every 30 days—to keep allergens under control.

Light Use or Seasonal Homes

If your furnace doesn’t run often, you may be able to replace the filter closer to the 90-day mark. Still, it should be checked monthly.

If you’re ever unsure, a visual check is a good rule of thumb. If the filter looks gray, dusty, or clogged, it’s time to replace it.

Signs Your Furnace Filter Needs to Be Changed

Sometimes your furnace gives you clues that the filter is overdue. Common signs include reduced airflow from vents, rooms that heat unevenly, or a furnace that seems to run longer than usual. You may also notice more dust settling on surfaces or worsening allergy symptoms indoors.

Ignoring these signs can lead to overheating, limit airflow across the heat exchanger, and increase the chance of system shutdowns or damage.

Not sure if your filter is the problem? Call (720) 780-9143 and let Applewood check your system.

What Happens If You Don’t Change Your Furnace Filter?

Skipping regular filter changes can create a chain reaction of problems. Restricted airflow forces your furnace to work harder, which increases energy consumption and utility costs. Over time, this strain can cause premature wear on motors, belts, and electrical components.

In severe cases, a clogged filter can cause the furnace to overheat and shut down as a safety measure. Repeated overheating can crack the heat exchanger—one of the most expensive components to replace.

Regular filter changes are one of the easiest ways to avoid unnecessary furnace repairs and extend the life of your heating system.

Choosing the Right Furnace Filter

Not all filters are created equal. Filters are rated by MERV (Minimum Efficiency Reporting Value), which measures how well they capture particles. While higher MERV ratings trap smaller particles, they can also restrict airflow if your system isn’t designed for them.

Applewood technicians can help you choose a filter that balances air quality and system performance. Using the wrong filter can cause as many problems as not changing it at all.

Professional Furnace Maintenance Makes a Difference

While changing your filter is something most homeowners can do, it’s only one part of proper furnace care. Annual professional maintenance ensures that your entire heating system is clean, safe, and operating efficiently.

During a heating maintenance visit, Applewood technicians inspect airflow, check filter fit, clean internal components, and identify issues before they become costly repairs. This service helps your furnace last longer and perform better throughout Colorado’s cold winters.

Schedule Furnace Service or Maintenance Today

Changing your furnace filter regularly is one of the simplest ways to protect your heating system—but it’s not the only one. Whether you need help selecting the right filter, scheduling furnace maintenance, or addressing airflow concerns, Applewood Plumbing Heating & Electric is here to help.

Call Applewood today at (720) 780-9143 to schedule furnace service.