Air purifier vs. large room HEPA air purifier: running cost
An air purifier is cheaper to run: about $63 a year versus $110 for a large room HEPA air purifier at typical use and 17.99¢/kWh, a $47 difference.
| Air purifier | Large room HEPA air purifier | |
|---|---|---|
| Typical watts | 40 W | 70 W |
| Watt range | 10–120 W | 30–150 W |
| Typical use | 24 hours a day | 24 hours a day |
| Energy per year | 351 kWh | 614 kWh |
| Cost per hour | 0.7¢ | 1.3¢ |
| Cost per day | 17¢ | 30¢ |
| Cost per month | $5.26 | $9.20 |
| Cost per year | $63 | $110 |
| Per year in Hawaii (43.51¢) | $153 | $267 |
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What drives the difference
- Air purifier: Room air purifiers draw about 10-60 W and are usually run 24/7, so a non-ENERGY STAR unit can use 300-500 kWh a year.
- Large room HEPA air purifier: Large-room purifiers rated for 500-1,500 sq ft draw 50-150 W on high but often run on Auto at 10-30 W.
Ways to cut either cost
Delivers more clean air per watt.
See options on AmazonA DIY box-fan filter is a low-cost option for occasional smoke events.
See options on AmazonFilters the whole house through existing ductwork whenever the HVAC fan runs.
See options on AmazonWe may earn a commission from qualifying purchases. It never changes the numbers we show. Disclosure.
Frequently asked questions
Which costs more to run, an air purifier or a large room HEPA air purifier?
At typical use and the U.S. average rate (17.99¢/kWh), a large room HEPA air purifier costs about $110 a year versus $63 for an air purifier. That's $47 more, or 1.8× as much.
How many watts do air purifier and large room HEPA air purifier use?
An air purifier typically draws 40 W (range 10–120 W). A large room HEPA air purifier draws 70 W (range 30–150 W). Watts alone don't decide cost. Hours of use, cycling and standby matter just as much.
Rates: EIA, 12 months ending 2026-07. Methodology.