PureAir Purifier Replacement Filters Guide
Filters are the real cost of owning an air purifier. Here's when to replace HEPA and carbon filters, what they cost, and how to keep running costs down without hurting performance.
Last updated: July 2026 · By the PureAir Lab editorial team
How often to replace each filter
| Filter | Typical life | What shortens it |
|---|---|---|
| True-HEPA | 6–12 months | Heavy dust, pets, running 24/7 |
| Activated carbon | 3–6 months | Smoke, strong odors, cooking |
| Washable pre-filter | Reusable (vacuum monthly) | Neglect clogs airflow |
These are general ranges. A purifier in a smoky or pet-heavy home works its filters harder, while a lightly used bedroom unit can reach the upper end. Many units also have a filter-replacement indicator, though those are timers rather than true sensors.
Signs it's time to change
- Noticeably weaker airflow on the same fan speed
- Odors returning even on high (carbon is saturated)
- Visible grey, packed dust across the HEPA pleats
- The filter indicator light comes on
Important with carbon: a saturated carbon filter can start re-releasing absorbed odors back into the room. If smells come back, change carbon promptly rather than waiting.
How to cut running costs
- Vacuum the pre-filter monthly. Catching coarse dust early protects the pricey HEPA and keeps airflow (and CADR) high.
- Run on auto. The fan only speeds up when needed, extending filter life versus running on high constantly.
- Check filter price before you buy the unit. A cheap purifier with costly proprietary filters can cost more over three years than a pricier one with affordable refills.
- Buy genuine or well-reviewed compatibles. Very cheap third-party HEPA filters sometimes aren't true-HEPA and can leak around the seal.
Three-year cost, not sticker price
When comparing models, add the purchase price to three years of filters. A $150 unit that needs $60 of filters a year costs $330 over three years; a $250 unit needing $30 a year costs $340 — nearly identical, but the second is often quieter and covers more area. This is why we always list filter type and availability in our reviews, such as our main buying guide.
FAQ
How often should I change my air purifier filter?
True-HEPA filters typically last 6–12 months and activated carbon 3–6 months, sooner in smoky or pet-heavy homes. Change carbon promptly once odors return.
Can I wash a HEPA filter?
Only if the manufacturer specifically says it's a washable HEPA. Standard true-HEPA filters are not washable — rinsing damages the fibers and ruins filtration. Washable pre-filters are fine to clean.
Are cheap replacement filters okay?
Well-reviewed compatibles can be fine, but avoid the cheapest no-name HEPA filters, which are sometimes only "HEPA-type" and may leak around the frame. Check that they're labelled true-HEPA and fit snugly.