Your Quick Guide to Furnace Filter Replacement Schedules

When the air becomes chillier, moving the action indoors is the best course to take to help you escape the wind’s cold grasp. People rely on the furnace to keep their homes warm and comfortable throughout the freezing winter months. However, a furnace with dirty filters can make your abode less welcoming.

One of the easiest furnace maintenance to increase your furnace’s efficiency is to change the filters. Replacing its filters can boost the efficiency of your furnace without breaking the bank.

How do you get a new furnace filter, and how often should you do it? This article will answer that and more.

When to Change Furnace Filters

How often to change a furnace filter? Furnace filters are responsible for catching dust, dirt, and debris that travels throughout your home via indoor supply ducts. When they’re clean, furnace filters can keep your home free from dust, allergens, and more. 

Dirty filters can become a source of air contaminants rather than be the one that eliminates them. In an ironic twist, the filter that was supposed to enhance air quality compromises it. When poor air quality continuously circulates in a home, health issues will abound.

There are many signs indicating the need to change filters. But if you notice that your energy bill increased while the airflow in your home decreased, you may want to check the filters and replace them when necessary.

How to Plan a Furnace Filter Replacement Schedule

Waiting for the signs to appear is an effective way to know when to change filters. But it can also be inefficient. Doing nothing and waiting for your energy bill to spike before replacing the furnace filters is a reactive action that causes you money. Meanwhile, knowing how frequently you need to change your furnace filters is a preventive action to save you money.

When planning a furnace filter replacement schedule, you need to consider the filter’s size, health conditions of people in your home, the sources of contaminants in your home, and the season.

One-Inch to Two-Inch Filters

When no one in your home has respiratory conditions or allergies, and you do not have additional sources of contaminants like construction projects and pets, changing the filter every three months is ideal. Otherwise, schedule replacements each month or every other month.

Four-Inch Filters

In case no one in your house has allergies, and you do not have additional contaminant sources, replacing the filter every six months is acceptable. If someone has allergies in your home or you have pets, you may want to schedule filter replacements every four months.

Five-Inch Filters

If your home does not have ongoing construction projects that can cause debris and dust to float around and no one in your home has respiratory conditions, replacing your furnace filters once a year is enough. Otherwise, you may want to change them every six months.

How to Replace Furnace Filters

In replacing furnace filters, remember to get the right filter for your furnace and be safe. Furnaces have heat sources and blow hot air. It means that you may get injured if you recklessly replace your furnace filters.


  1. Turn off the thermostat and the furnace. It is best to temporarily unhook it from the power source if possible.
  2. Carefully slide the old filter out. The filter is typically located in the lower portion of the furnace, where the return register duct meets the blower chamber.
  3. Slide the new one in, orienting it similarly to the old filter.
  4. Switch everything on and test the system.


Furnace maintenance is important to help your furnace run optimally at all times and keep your home warm, welcoming, and cozy, especially during winter. Setting up a furnace filter replacement schedule ensures that you do not have to suffer from high energy bills and inconsistent airflow.

If you are looking for one of the best HVAC contractors in Calgary and Edmonton, turn to Legacy Heating & Cooling. We are a BBB-accredited business that offers a wide array of HVAC services, from furnace replacements to HRV installations. Contact us for a free quote today!

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