How Often To Change a Furnace Filter
Typical Cost Range: $5 – $100
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A furnace filter is an essential but sometimes overlooked component of your home heating system. It prevents dust, dirt, and other airborne particles from clogging your HVAC system while also improving your home’s air quality. The furnace filter needs routine replacement to remove these particles and debris. In general, you should change it every 2–3 months or whenever it looks dirty, but we’ll outline several factors that affect how often you should change your furnace filter.
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How Often Should You Change Your Furnace Filter?
Over time, particles become trapped in the furnace filter, restricting airflow through your heating system. This forces the furnace to work harder, which can result in a higher heating bill and eventually shorten the furnace’s life.
Check the manufacturer’s recommendations on how often to change your furnace filter, but the typical suggestion is every 60–90 days. This also depends on your system’s age and how often it’s used. The EPA suggests checking your filter once per month, especially during winter, and changing it if it looks dirty. Change the furnace filter every three months at a minimum.
If you have a HEPA (high-efficiency particulate air) filter, you may be able to replace it less often than a fiberglass filter, and some are even washable. This type of air filter removes at least 99.97% of dust, pollen, mold, bacteria, and other airborne particles with a size of 0.3 microns. HEPA air filters require replacement once per year.
Filter Types and Costs
Review your air-filter options in the video below with This Old House plumbing and heating expert Richard Trethewey.
What Does a Furnace Filter Do?
A furnace filter protects your home from dust, hair, debris, and other contaminants that come in through your HVAC system’s return duct. Without a filter, debris and other particles will collect in your heating system, which could affect your furnace’s energy efficiency. The furnace filter also improves your home’s indoor air quality by removing potential irritants and allergens from the air. This is especially important for anyone with allergies or asthma.
- Your filter’s ability to trap particles depends on its MERV (minimum efficiency reporting value) rating. According to the U.S. Environmental Protection Agency (EPA), MERV measures a filter’s ability to capture large particles between 0.3 and 10 microns.
A higher MERV rating means the filter is better at trapping these particles, but it will need to be changed more frequently than a filter with a lower MERV rating. The most common type of filter is a disposable pleated furnace filter, but there are several options with different MERV ratings. Most residential furnace filters have a MERV rating of 7–12, but anything 13 or over is considered a high-efficiency filter. Most modern furnaces are compatible with high-efficiency filters, but if you have concerns, speak to an HVAC technician.
Reasons To Change Your Furnace Filter More Often
The following factors also affect how often to change a furnace filter.
DIY vs. Professional Furnace Filter Cleaning
Most homeowners can handle basic furnace filter replacement. However, you should schedule annual preseason check-ups with an HVAC contractor, ideally in spring and fall. Unless you have the skills and training necessary to clean the other internal components of a furnace, that part of maintenance should be left to a professional.
A technician will inspect and clean the system’s components to ensure your furnace runs efficiently. Duct cleaning isn’t considered part of yearly maintenance, but it may improve your home’s indoor air quality if done every few years.
Professional Furnace Cleaning
A professional furnace cleaning typically costs between $60 and $400, with an average cost of about $150. Electric and gas furnaces cost about the same to clean, but oil furnaces are more expensive. Here are some of the specific tasks involved in furnace cleaning:
- Inspecting the vent system and air intake for blockages
- Cleaning the blower and checking the motor
- Lubricating all moving parts
- Cleaning the combustion chamber
- Inspecting the flue pipe
- Testing component efficiency
- Replacing the oil filter
- Checking the air filter and replacing it if necessary
Regular furnace cleaning performed by a professional improves the system’s performance, safety, and longevity. You can also catch problems early, like a crack in the heat exchanger that only a trained technician might notice. This may save you money in the long run.
DIY Furnace Cleaning
Our Conclusion
A clean furnace improves your home’s indoor air quality and increases your heating system’s performance and lifespan. You can replace a furnace filter on your own, but routine maintenance should be performed by a skilled technician. Furnace cleaning can be complex and potentially dangerous, especially if you’re unfamiliar with the necessary equipment and safety procedures.
FAQ About Changing Your Furnace Filter
What happens if I don’t change my furnace filter?
If you don’t change your furnace filter, the filter can become clogged so that little air passes through. A clogged filter can damage your HVAC system and allow contaminants to circulate through your home.
Do furnace filters really last three months?
Most air filter manufacturers say to replace the furnace filter every 90 days. However, this depends on other factors, such as your home’s location, if you have allergies or respiratory issues, and your system’s age. You may need to replace it more frequently.
How often should you change your furnace filter in winter?
The general rule for how often to change a furnace filter is every 2–3 months, but because you use your furnace more during winter, it can become dirty quickly and should be checked more frequently.
What are the symptoms of a dirty furnace filter?
The most common symptoms of a dirty furnace filter are higher heating bills, poor air quality, and bad airflow. You may also notice uneven heating from one room to the next or a burning smell when your furnace kicks on.
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