When You Should Replace Your Furnace Filter & How To Do It

Maintaining the furnace in your home is an important task to ensure the health and efficiency of your heating system. But one aspect of furnace maintenance that is often overlooked is the furnace filter. Regularly replacing your furnace filter is essential to keep your heating system running smoothly and to improve the air quality in your home. It’s something we always recommend alongside our list of maintenance tips for winter

In fact, changing the filter in your furnace is one of the simplest and most cost-effective things you can do to improve the performance of your heating system and the air quality in your house. But how do you go about replacing the filter in your furnace? Not to worry; this article will provide a step-by-step guide on when and how to change furnace filters and offer maintenance tips as well.

Types of furnace filters available

When it comes to choosing a replacement furnace filter, there are several options available. Fiberglass filters are the most economical choice, but they are not as effective at trapping pollutants as other types of filters. Pleated filters are more efficient at trapping particles and can last longer, but they are relatively more expensive.

Washable filters can be a more environmentally friendly option, but they may not be as effective as disposable filters and may require more maintenance. When selecting a furnace filter, it is important to consider factors such as the MERV rating, size, and cost.

The most expensive filters are reusable electrostatic filters. These filters are intended to catch even tiny airborne particles and smoke, making them ideal for the most demanding environments. 

Filters such as the multi-stage electrostatic air filters can be washed clean with a garden hose whenever they get dirty and reused for a number of years provided they are maintained in the appropriate manner.

Some filters, available in both disposable and reusable varieties, have been given the rating of “antimicrobial” or “high-efficiency particulate air” (HEPA), indicating that they have been specially treated to capture microorganisms such as bacteria, yeast, fungus, mold, and algae. These filters also have a HEPA rating. If there is a member of your family who suffers from allergies, purchasing this kind of filter can be a good idea.

How often should you change your furnace filter? 

The frequency of replacement will depend on several factors, such as the size of your household, the presence of pets, and any allergies or sensitivities to pollutants in the air. As a general rule, standard fiberglass furnace filters should be replaced every 30 to 90 days, while pleated furnace filters can last up to six months.

The Merv rating system can also be used to determine the appropriate replacement frequency for your furnace filter. The Merv rating measures the efficiency of the filter in trapping airborne particles, with higher ratings indicating a more effective filter. Filters with a Merv rating of 8 or above should be replaced every three months, while those with a rating of 11 or higher should be replaced every month.

Now that you know how often to replace your furnace filter, let’s move on to the process of actually replacing it. 

Breaking down how to change the furnace filter

One of the biggest questions we get is on how to change the furnace air filter. The process is relatively simple, but it is important to follow the steps carefully to ensure proper installation.

  • Turn off the power to your furnace by flipping the switch or turning off the circuit breaker.
  • The first step is to locate and access your furnace filter. This is typically located in the return air duct or the blower compartment of your furnace. Depending on the specific design of your furnace, you may need to slide the old filter out or remove screws to access it.
  • Carefully remove the old filter. Be sure to dispose of it properly, as it may contain particles and pollutants that can be harmful to the environment.
  • Measure the size of the filter to ensure that you have the correct replacement.
  • Hold the new filter up to the opening where the old filter was located to confirm that it is the correct size.
  • If the filter is the correct size, slide it into place or reattach it with screws as necessary.
  • Turn the power back on to your furnace.
  • It is important to make sure that the filter is properly installed and oriented in the correct direction. Most filters will have an arrow indicating the direction of airflow, so be sure to align the arrow with the direction of the airflow in your furnace.

In addition to replacing your furnace filter on a regular basis, there are a few points you can keep in mind to maintain the efficiency of your heating system.

  • It is important to remember that replacing your furnace filter is not a one-time task. It is necessary to regularly replace your furnace air filter to ensure the health and efficiency of your heating system. By replacing your filter on time, you can improve the air quality in your home and potentially save on energy costs.
  • Taking care can be as simple as checking the filter for dirt and debris and vacuuming or cleaning it as needed. This can help to prolong its lifespan. If you have a washable filter, be sure to follow the manufacturer’s instructions for cleaning and drying it before reinserting it into the furnace.

By taking these simple steps, you can prolong the lifespan of your furnace filter and ensure that your heating system is running smoothly and efficiently.


Replacing your furnace filter on a regular basis is an important aspect of maintaining the health and efficiency of your heating system. By following the steps for how to replace furnace filters and maintaining them properly, you can improve the air quality in your home and potentially save on energy costs.

Don’t neglect this important aspect of furnace maintenance – make sure to regularly replace and maintain your furnace filter to keep your heating system running smoothly. If you’re unsure about how to change your furnace filter, it’s a good idea to refer to your furnace manual or contact a professional, such as Autumn Air, for guidance.

You may either give us a call at (602) 266-5247 or use this online form to arrange for service.