Large room HEPA air purifier vs. dehumidifier: running cost
A large room HEPA air purifier is cheaper to run: about $110 a year versus $158 for a dehumidifier at typical use and 17.99¢/kWh, a $47 difference.
| Large room HEPA air purifier | Dehumidifier | |
|---|---|---|
| Typical watts | 70 W | 500 W |
| Watt range | 30–150 W | 250–750 W |
| Typical use | 24 hours a day | 24 hours a day for 6 months a year |
| Energy per year | 614 kWh | 877 kWh |
| Cost per hour | 1.3¢ | 3.6¢ |
| Cost per day | 30¢ | 86¢ |
| Cost per month | $9.20 | $26.28 |
| Cost per year | $110 | $158 |
| Per year in Hawaii (43.51¢) | $267 | $381 |
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What drives the difference
- 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.
- Dehumidifier: A 50-pint dehumidifier draws about 450-550 W while the compressor runs; the humidistat cycles it, so defaults give about 880 kWh over a humid season.
Ways to cut either cost
Filters the whole house through existing ductwork whenever the HVAC fan runs.
See options on AmazonRemoves more moisture per kWh than older units.
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Frequently asked questions
Which costs more to run, a large room HEPA air purifier or a dehumidifier?
At typical use and the U.S. average rate (17.99¢/kWh), a dehumidifier costs about $158 a year versus $110 for a large room HEPA air purifier. That's $47 more, or 1.4× as much.
How many watts do large room HEPA air purifier and dehumidifier use?
A large room HEPA air purifier typically draws 70 W (range 30–150 W). A dehumidifier draws 500 W (range 250–750 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.