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A cheap air purifier can cost more to own than a pricier one once you add up filters. Enter the power draw, hours of use and filter costs to see what a purifier really costs per year — and over five years.
Where to find the numbers
- Power draw: listed in watts in the manual, usually per fan speed. Use the speed you’ll run most of the time — often low or auto.
- Filter life: manufacturers quote months of use, sometimes assuming 24/7 operation.
- Electricity price: on your bill, in cents per kWh.
Typical costs
| Purifier size | Power on medium | Electricity / year (12 h/day, $0.17/kWh) |
|---|---|---|
| Small bedroom unit | 10–25 W | $7–19 |
| Mid-size living room unit | 25–50 W | $19–37 |
| Large-room unit | 50–100 W | $37–74 |
FAQ
Do generic filters save money?
Often, but check that they’re true HEPA and fit tightly — a gap around the filter lets air bypass it and reduces real-world CADR.
Should I run a purifier 24/7?
For allergies or smoke, continuous use on a low or auto setting usually beats short bursts on high, and it’s quieter.
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