Air Filter Replacement Guide
Written by Muneeb Rana · Last updated 21 October 2026
Quick answer: Air filter replacement covers two filters. The engine air filter is typically replaced every 15,000-30,000 miles, sooner on dusty roads. The cabin air filter, which cleans air entering the passenger compartment, is often replaced every 15,000-25,000 miles or once a year. Both are usually quick, cheap DIY jobs. Your manual gives the exact intervals.
TL;DR
- Engine filter: often 15,000-30,000 mi; sooner in dust.
- Cabin filter: often yearly or 15,000-25,000 mi.
- Both are easy DIY jobs on most cars.
Air filter replacement is one of the easiest ways to save money on servicing, because both filters are often a few minutes' work with no tools. Here's when each one is due.
Engine vs cabin filter
| Engine air filter | Cabin air filter | |
|---|---|---|
| Cleans | Air entering the engine | Air entering the cabin |
| Where | Box on top or side of the engine | Usually behind the glovebox |
| Typical interval | 15,000-30,000 mi | 15,000-25,000 mi or yearly |
| Signs | Sluggish acceleration, dirty filter | Weak airflow, musty smell, more dust or pollen |
Does a dirty air filter hurt fuel economy?
Less than many people think. FuelEconomy.gov says replacing a clogged air filter on modern fuel-injected, computer-controlled cars doesn't improve fuel economy, though it can improve acceleration. On older carbureted engines, it can improve economy. So replace it for performance and engine protection, not MPG.
How to check and replace
Open the airbox clips, lift out the filter and hold it up to light. If light barely passes through, or it's full of debris, replace it with the exact part for your engine. Cabin filters slide out behind the glovebox on many cars. Note the airflow arrow.
Log it and save
Doing filters yourself can noticeably cut a 15,000 mile service bill. Log the date and mileage in CarO and add filters to your car maintenance checklist. New to DIY? Start with car maintenance for beginners or the maintenance schedule tool. The maintenance cost calculator shows how small jobs add up.
Download CarO free on the App Store or Google Play. Free with ads; optional in-app purchases.
Sources
- FuelEconomy.gov: Keeping Your Vehicle in Shape: www.fueleconomy.gov (accessed 21 October 2026)
- AAA: Time-Stamped Car Maintenance Checklist: www.aaa.com (accessed 21 October 2026)
- Toyota: Maintenance Schedule (owners): www.toyota.com (accessed 21 October 2026)
Disclaimer: CarO and this website give general car-care information, not professional advice. Maintenance intervals and specifications vary by vehicle, so always follow your owner's manual and a qualified mechanic. Mileage and cost figures are estimates; check local tax rules before using any log for deductions.
FAQ
How often should I change my engine air filter?
Often every 15,000-30,000 miles, more often on dusty or unpaved roads. Check your manual.
How often should I change my cabin air filter?
Often once a year or every 15,000-25,000 miles, more often if you have allergies or drive in polluted areas.
Does a new air filter improve MPG?
Not on modern fuel-injected cars, according to FuelEconomy.gov. It can improve acceleration.
Can I replace air filters myself?
Yes, on most cars both are simple jobs with few or no tools.
What happens if I never change the cabin filter?
Airflow drops, the AC and heater work harder, and more dust, pollen and odours get into the car.
Related guides
Track this in CarO
CarO is a free car maintenance tracker app for iPhone and Android that keeps a full service history, reminds you about oil changes and inspections by mileage or date, and logs fuel fill-ups with MPG, odometer readings and car expenses for every vehicle you own. Logs are stored in the cloud and can be exported as CSV.
