Summit Heating & AC Answers, How Often Do I Need to Replace My Furnace Filter?
Ask most people this question, and they’ll tell you, “Every three months.” And while this is correct in many cases, the answer isn’t nearly that simple.
The correct answer is, “It depends.” Many factors can influence how frequently your filters should be changed, from your local climate to pet ownership, type of filter to allergy issues. Below, Summit Heating and Air Conditioning will go over all the factors that can influence your timetable and suggest some general rules of thumb.
The quality of your filter can alter how frequently you need to change it. MERV is a rating system designed to tell you the size of the particles your filter will capture. Low MERV ratings indicate the filter only captures the largest particles, meaning a lot of smaller particles will pass right through. As the MERV rating goes up, smaller and smaller particles are captured. This means higher MERV rated filters are more effective for more contaminants.
Unfortunately, some big box home improvement stores like Home Depot have abandoned MERV for their own standard, FPR. But the concept is the same. The higher the FPR, the better the filter performance.
Most standard filters in the U.S. are a MERV 8, which corresponds to an FPR 5. These should be checked every two to three months. Lower MERV ratings catch fewer particles, so they can be checked less frequently. Very high MERV ratings should be checked every month.
Indoor Air Quality
If you use air purifiers throughout your house, they’re already doing a lot of the heavy lifting. If you have very good indoor air quality, your furnace filter won’t be working as hard, and you can check it less frequently.
On the other hand, if you have poor indoor air quality, and your filter is the only item cleaning contaminants, check it more regularly.
If you live in a temperate area where your HVAC system doesn’t need to run frequently, then your filter isn’t used as much, allowing you to check it less often.
However, here in the Denver Metro area, we have cold winters and warm summers, so our systems run regularly, particularly at the height of each season. Dean Peterson is a co-founder of Summit Heating & AC in Denver, Colorado. He stated that, “this is fairly average use, so our climate doesn’t really modify the recommended changing schedule.”
Pets contribute quite a bit to indoor air pollution. Hair, dander, pollen and other contaminants either flake off our pet or get carried in from outside. All this extra dust adds strain to your filter. If you have a pet, you should check it more regularly, and the more pets you have, the more frequently you should change the filter.
If any member of your household suffers from allergies, asthma or other respiratory issues, it’s imperative that you keep your indoor air quality high. This means changing your filter far more frequently than usually recommended. Depending on the other factors listed above this could range anywhere between every 20 to 45 days.
Rules of Thumb
These general guidelines are good to get you started, but the best way to know how frequently to change your filter is to check it every month. If it isn’t dirty, or only slightly dirty, recheck it a month later. Keep doing this until you find the filter covered in a visible layer of dust across its entire surface. If it’s very dirty, change it a little earlier next time. If not, then you’ve found a good schedule for your specific situation. Bear in mind allergies, and other conditions may require a filter change before it’s visibly dirty.
- Standard filter, no other issues: Every three months
- Standard filter, great indoor air quality: Every 4-6 months
- Standard filter, poor indoor air quality: Every two months
- Standard filter, pets: Every two months
- Standard filter, allergies/asthma: Every six weeks
- Standard filter, pets, and allergies: Every 20 days
If you have any questions about your furnace filter, consider giving Summit a call. They can easilyhelp you determine how frequently you should be checking and changing it.
About Summit Heating and Air Conditioning:
At Summit Heating & AC we’ve been in business for 20 years, with a proven track record of excellent service and satisfied customers. All of our technicians are fully licensed, bonded, and insured, with the experience to the job right, the first time. We’d love the opportunity to come out and discuss your options and give you a written estimate. Call our N.A.T.E. certified experts today.