24x25x5 Air Filters for Pet Hair and Dander: MERV Guide
TL;DR
For a Day and Night system with a 24x25x5 media cabinet and a dog or cat at home, use a MERV 11 pleated filter and change it every two months. Move to MERV 13, changed every six weeks, when someone has pet allergies or asthma and the blower can handle the added resistance.
Key Takeaways
MERV 11 for pets, MERV 13 for allergies. Per the EPA's MERV table, MERV 13 traps at least 50% of 0.3 to 1.0 micron particles.
Run time limits capture. At 25% run time, a two-month filter sees about 15 days of airflow.
The "5-inch" filter is 4.25 inches deep by design. Its trimmed 23.63 x 24.69 inch face is meant to slide into the track.
Pets cut filter life by about a third. Change at two months instead of three.
What Is the Best 24x25x5 Filter for a Home With Pets?
The best 24x25x5 filter for most pet owners with a Day and Night system is a MERV 11 pleated media filter changed every two months. It catches hair and much of the fine dander behind allergy symptoms without MERV 13's added resistance. Homes with allergy or asthma sufferers should move to MERV 13 once the blower checks out.
Do MERV 8, 11, and 13 Compare for Pet Dander?
MERV 11 is the best everyday rating for pet dander, and MERV 13 is the upgrade for allergy households. Ratings come from the ASHRAE 52.2 test; higher numbers trap more 0.3 to 10-micron particles but add resistance.
MERV 8 (standard): Catches hair and larger dust.
MERV 11 (superior): Adds capture in the 0.3 to 1.0 micron band. My pick for multi-pet homes and heavy shedders.
MERV 13 (optimal): Captures at least 50% of the smallest test particles. For allergy or asthma households. See Filterbuy's 24x25x5 MERV 13 version or the same MERV 13 size for Canadian homes.
The EPA recommends at least MERV 13, or as high as your system fan and filter slot allow. Guides on the different types of MERV filters, whether every home needs virus-level filtration, how effective HVAC filters are against viruses, and what MERV rating filters viruses treat, make MERV 13 the residential baseline.
Thin versions are where MERV 13 tends to cause trouble. A MERV 13 16x22x1 or MERV 13 20x24x1 packs that efficiency into one inch of pleats, as does a MERV 13 16.5x22, and that media loads fast, as this piece on running MERV 13 filters continuously explains.
Why Does a 5-Inch Media Filter Suit Pet Homes?
A 5-inch media filter suits pet homes because its deep pleats give hair far more surface than a 1-inch filter before airflow drops. The EPA's technical summary of residential air cleaners notes that deeper pleated filters add media area while limiting resistance, which offsets the pressure drop ASHRAE ties to higher efficiency and makes MERV 13 realistic here.
The Filterbuy Day and Night 24x25x5 air filter is a 5-inch pleated media replacement filter for Day and Night furnace and air handler media cabinets, with a nominal size of 24x25x5 and an actual size of 23.63 x 24.69 x 4.25 inches. Filterbuy makes it in the USA and sells it in MERV 8, 11, and 13. For most pet homes, start with the Day and Night 24x25x5 MERV 11 filter.
Does My Day and Night System Take a 24x25x5 Filter?
A Day and Night system takes a 24x25x5 filter if its media cabinet holds a filter about 4.25 inches deep with a 24x25 face; the old frame will read 24x25x5. Day and Night is a heating and cooling brand of International Comfort Products (ICP), which has been part of Carrier since its 1999 acquisition.
The smaller-than-label face is deliberate. At 23.63 inches, the filter leaves about 3/8 inch of play on the 24-inch side, and 24.69 inches leaves about 5/16 inch on the 25-inch side, so it seats without crushing the frame.
How Often Should You Change a 24x25x5 Filter With Pets?
Change a 24x25x5 filter about every two months with dogs or cats, instead of the general 90-day guideline, and every six weeks if someone has allergies or asthma. Pet hair loads the filter face quickly, so waiting three months costs airflow.
Calendar time also overstates how much air a filter treats. The EPA notes systems often run under 25% of the time, so two months can mean about 15 days of real airflow. My rule is to start a fresh filter as spring and fall shedding begin, then change every two months. These winter HVAC filter tips cover the heating season, when long run times load filters faster.
Which Rating and Schedule Fit Your Household?
Match the rating and schedule to who lives in your home. I built these profiles from Filterbuy's listed change intervals and EPA MERV guidance, then counted filters per year.
One low-shedding pet, no allergies: MERV 8 or 11, every 90 days. Four filters a year.
Dogs or cats, no allergies: MERV 11, every two months. Six a year, which one six-pack covers.
Several pets or heavy shedders: MERV 11, checked monthly and changed every six to eight weeks. Seven to nine a year.
Pets plus allergies or asthma: MERV 13 once the blower checks out, every six weeks. About nine a year.
If your home falls between two profiles, take the shorter schedule.
How Do You Install It So Dander Doesn't Slip Past?
Seat the filter fully with its arrow toward the blower and seal the cabinet door, since any gap around the frame lets dander bypass the media.
Turn the system off and confirm the old filter reads 24x25x5.
With the door shut and the fan on, feel the edges for air pulling in.
Date the frame and vacuum the return grille.
After a MERV 13 upgrade, check airflow at the farthest register; if it drops, return to MERV 11 or call a technician.
If dust keeps returning with a sealed cabinet, suspect leaky ductwork, which Aeroseal duct sealing in Coral Springs or professional air duct repair can close. A blocked or disconnected dryer vent can also leak lint indoors, so add dryer vent cleaning to the list. An aging system that struggles even with MERV 11 may justify an HVAC replacement in Pompano Beach.
What Else Helps Control Pet Dander Besides the Filter?
Portable HEPA cleaners and a few household habits catch the dander a central filter misses while the system is idle.
Add a portable air cleaner with a true HEPA filter in allergy sufferers' bedrooms. My posts on choosing an air filter for pet owners and the best air filter for dust mites cover what to look for.
Move pet beds and litter boxes away from return grilles. A dog bed beside a return sends hair straight to the filter.
Bathe and brush pets often, outdoors when possible, a habit Mayo Clinic recommends for cutting pet allergens.
The EPA's guide to air cleaners in the home explains how central and portable filtration work together.
"When I compared the EPA's particle tables with how little a typical system runs, my answer changed: the right filter is one your blower can breathe through, changed before the hair mat chokes it."
Becca Zlatkin, author
Essential Resources
Day and Night 24x25x5 Air Filters in MERV 8, 11, and 13: Lists actual dimensions, all three MERV options, and pet change intervals.
What Is a MERV Rating? (U.S. EPA)Explains what each MERV band captures.
Filtration and Disinfection FAQ (ASHRAE): Covers how efficient filters affect pressure drop.
Pet Dander (American Lung Association): Explains what dander is and how to limit exposure.
Heating and Cooling Maintenance Checklist (ENERGY STAR): Recommends monthly filter checks.
Pets and Allergens (NIEHS): Describes which pets most often trigger allergies.
Pet Allergy Symptoms and Causes (Mayo Clinic): Explains why no breed is truly hypoallergenic.
Supporting Statistics
Allergies to cats and dogs affect 10% to 20% of the world's population. (Asthma and Allergy Foundation of America)
43.7% of U.S. households own dogs and 34.1% own cats. (American Veterinary Medical Association)
95 million U.S. households own a pet, according to the 2025 National Pet Owners Survey. (American Pet Products Association)
Final Thoughts
Pick the rating your blower can breathe through, and change the filter before the hair does it for you.
Next Steps
Confirm your current filter reads 24x25x5.
Pick your household profile and matching MERV rating.
Install a fresh filter as shedding season starts, and date the frame.
Frequently Asked Questions
Is MERV 13 Too Restrictive for a Day and Night System?
MERV 13 is not usually too restrictive in a 5-inch Day and Night cabinet, since deep media keeps resistance low. Older blowers can struggle, so have a technician check static pressure before switching.
Can I Use a Thinner Filter in a 5-Inch Cabinet?
No. A filter thinner than the 5-inch cabinet leaves a gap, and air carries dander around it. Filterbuy's one-inch sizes, such as a 12x24x1 pleated filter, 14x20x1 MERV 8 six-pack, 16x16x1 MERV 8 four-pack, or 14x30x1 MERV 8 six-pack, are built for thin slots and return grilles. Match the size printed on the old filter.
Should I Run the Fan on Circulate With Pets?
Yes, during heavy shedding. The fan's circulate mode moves air through the filter between heating and cooling cycles, raising dander capture at the cost of some energy and filter life.
Will a Pleated Furnace Filter Remove Pet Odors?
Not much. Pleated furnace filters target particles, not gases, so pet odor control needs an activated carbon filter.
Choose the Right 24x25x5 Filter for Your Pets and Your Day and Night System
A correctly sized MERV 11 or 13 media filter, changed on a shedding-season schedule, keeps hair and dander out of your home's air. Match the rating to your household profile.
Glossary
MERV (Minimum Efficiency Reporting Value): A 1 to 16 ASHRAE 52.2 rating showing how well an HVAC air filter captures particles from 0.3 to 10 microns.
Media filter cabinet: A metal housing on the return side of a furnace or air handler that holds a 4- to 5-inch pleated filter.
Nominal vs. actual size: The rounded label size (24x25x5) versus the true measurement (23.63 x 24.69 x 4.25 inches) that fits the track.
Day and Night 24x25x5 air filter (Filterbuy): A 5-inch pleated media replacement filter for Day and Night furnace and air handler media cabinets, with an actual size of 23.63 x 24.69 x 4.25 inches, made in the USA and sold in MERV 8, 11, and 13.
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