Changing the filter in your furnace is one of the easiest things to do around the house, but it’s also one of the most common things that people forget to do. This tiny part has a big effect on how well your HVAC system works, how much energy it uses, and how clean the air is in your home.
The short answer to the question, “How often should I change my furnace filter?” is that most homes should do it every two to three months. But that’s just a starting point. Depending on pets, allergies, dust levels, and the type of filter being used, many homes need replacements more often.
Let’s go over everything you need to know about how often to change your furnace filter, why it matters, and how to tell when it’s time for a new one.
Why you should care more about furnace filters than you think
The filter in your furnace does two very important things: it keeps dust and debris out of your HVAC system and it helps clean the air that your family breathes. A clean filter lets air flow freely, which keeps your furnace from working too hard and helps it work well.
Ignoring it has the opposite effect. When your filter is clogged, your furnace has to work harder, which costs you more money. At the same time, dust, pollen, and pet dander slip through and circulate through your home. This can make your HVAC system last less long and make your allergies or asthma worse over time. If left too long, a clogged filter can even contribute to your furnace shutting down unexpectedly.
When should you change the filter in your furnace?
Every 60 to 90 days, you should change your furnace filter. That’s the general rule. Most manufacturers and groups like the EPA recommend that schedule.
But keep in mind that this is just the beginning and not the only answer. During the months when you use it a lot, like winter when the furnace is always running or summer when you use central air, you should check it more often. You might be able to go the whole 90 days in the spring and fall.
What Makes the Schedule Change?
A filter can get clogged more quickly and need to be changed more often for a number of reasons:
- Having pets in the house: Pet hair and dander fill up a filter quickly, so you may need to change it every 30 to 60 days.
- If anyone in your house has asthma or allergies, changing the filter every month to six weeks can help lower the number of things that set them off.
- Living near a busy road, construction site, or farmland means more particles in the air and more frequent filter changes.
- Home size: Bigger homes have more air flow, which means that more dust and debris get through the system.
In short, the “every 2–3 months” rule works for a lot of homes, but families with pets, allergies, or more dust should do it more often.
What is the difference between a furnace filter and a home air filter?
People sometimes use the terms “furnace filter” and “home air filter” to mean the same thing. In most homes, the filter in your HVAC system is the same thing as the one that comes with it. It protects the furnace and makes the air inside better.
Some houses, on the other hand, have extra air purification systems that use different filters. Depending on how they are made, these may need to be changed on a different schedule, and sometimes even more often. No matter what the terms are, the main rule is to check it every month and change it before it looks dirty or clogged.
How to Tell When It’s Time for a Change
You don’t have to depend on the calendar alone. Your furnace and home will usually let you know when the filter is no longer working well.
When you notice that the air coming from the vents is weaker, that dust is building up on surfaces, or that your utility bills have suddenly gone up, the filter is usually the problem. It’s also a strong sign if your allergies get worse or your furnace starts blowing cold air. And of course, if the filter looks gray, dusty, or clogged when you take it out, it’s time to get a new one.
How Long Do Different Kinds of Filters Last?
Not all furnace filters are the same, and the material and design affect how long they last.
- Fiberglass filters are the least expensive, but they only last about 30 days.
- Most homes should use pleated polyester filters, which last between 60 and 90 days.
- HEPA filters can last up to a year and filter out particles like those found in hospitals. However, not all systems are made to handle them.
- High-MERV filters catch very small particles, but they may get clogged faster and need to be replaced in as little as 30 to 60 days.
When picking a filter, you need to think about how much it costs, how well it works, and how sensitive your family is to dust and allergens.
What Will Happen If You Don’t Change the Filter?
You might not think it’s a big deal to skip changing the filter, but over time, the effects add up. A clogged filter makes your furnace work harder to push air through, which uses more energy and shortens its life. Bad air quality inside can make surfaces dustier and make allergy or asthma symptoms worse.
If you don’t clean the filter for too long, your furnace may overheat and stop working, or it may damage important parts like the blower motor. In many cases, homeowners end up facing repairs like furnace ignitor replacement because of poor maintenance. What seems like a small job can save you a lot of money on repairs later. What seems like a small job can save you a lot of money on repairs later.
Can You Replace It Yourself?
Changing a furnace filter is a simple do-it-yourself task for most homeowners. To change the filter, just turn off the system, take out the old one, check its size, and put in a new one with the airflow arrow pointing in the right direction.
If you’re not sure what kind of filter to use or if your furnace is having bigger problems, it might be best to call a professional. Many homeowners set up seasonal maintenance visits where the technician changes the filter and checks to make sure the rest of the system is working properly. You can also learn more about the full range of furnace services available to keep your heating system running at peak efficiency.
Frequently Asked Questions
Q1. How often should you change your furnace filter?
Most homeowners should replace their furnace filter every 60 to 90 days. If you have pets, allergies, or live in a dusty area, check it monthly and change it sooner when it looks dirty.
Q2. How often should I change my furnace filter with pets?
Homes with cats or dogs usually need a new furnace filter every 30 to 60 days because pet hair and dander clog filters quickly. Multiple pets may require even more frequent changes.
Q3. How often should you change your home’s air filter in winter and summer?
During peak heating and cooling seasons, filters should be changed every 30 to 60 days. Systems run more often in winter and summer, which causes filters to fill faster.
Q4. How often should you change your home’s air filter if you have allergies?
For households with allergies or asthma, replacing the filter every 30 to 45 days helps keep indoor air cleaner and reduces allergy symptoms.
Q5. Can furnace filters be cleaned and reused?
Disposable filters cannot be washed and reused — they must be replaced. Only washable or reusable filters can be cleaned, and they should be rinsed and dried before being reinstalled.
Q6. What MERV rating should I use for my furnace filter?
For most residential furnaces, a MERV rating between 8 and 13 provides a good balance of efficiency and air quality. Higher ratings may trap more particles but can also restrict airflow if your system isn’t designed for them.
Q7. What happens if you don’t change your furnace filter regularly?
A clogged filter reduces airflow, makes the furnace work harder, increases energy bills, and can even cause system breakdowns. It also lowers indoor air quality.
Conclusion
It may seem like a small thing to change your furnace filter, but it makes a big difference. You can keep your furnace running well, save money on energy, and make the air in your home better by checking it once a month and changing it every two to three months.
Schedule professional HVAC maintenance if you want an extra layer of protection. Not only will a technician change the filter, but they will also look for problems in the system before they become expensive repairs. If your thermostat isn’t responding properly, it could also affect your heating, so knowing why your thermostat may not be turning on the heat is equally important.
