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Air purifier electricity cost calculator
What does it cost to leave an air purifier running? Enter its wattage, how long it runs and your electricity rate. Add the filter price for the full yearly cost.
US homes pay about 18¢ per kWh on average. Your bill shows your exact rate.
- Electricity per month
- Filters per year
- Total cost per year
- Clean air per watt
Affiliate link. ENERGY STAR purifiers must meet a minimum clean air output per watt.
The formula
cost per year = watts × hours per day × 365 ÷ 1000 × $ per kWhWatts ÷ 1000 gives kilowatts. Multiply by hours of use to get kilowatt-hours (kWh), which is what your utility bills for. Add the yearly filter cost for the total cost of running the purifier.
A purifier drawing 30 W around the clock uses 30 × 24 × 365 ÷ 1000 = 263 kWh a year. At 18¢ per kWh that's about $47 a year, or under $4 a month. Two $40 filters a year add $80, so here filters cost more than electricity.
Yearly cost by wattage (at 18¢/kWh)
| Draw | Typical of | 8 h a day | 24 h a day |
|---|---|---|---|
| 5 W | Efficient purifier on low | $2.63 | $7.88 |
| 15 W | Small purifier on high | $7.88 | $24 |
| 30 W | Mid-size purifier, medium | $16 | $47 |
| 50 W | Mid-size purifier on high | $26 | $79 |
| 100 W | Large purifier on turbo | $53 | $158 |
Wattages are typical ranges, not specific models. Label ratings are usually the maximum draw on the top speed. For the real figure at your setting, use a plug-in power meter (affiliate link).
What actually drives the cost
- Fan speed matters most. Fan power rises much faster than airflow, so the top speed can use several times the power of a medium setting. A bigger purifier on low is usually the efficient choice, and the quieter one.
- Filters often cost more than power. For an efficient purifier, a year of electricity can cost less than a single replacement filter. Before you buy, check the filter price and whether you can easily get replacements.
- Compare clean air per watt, not watts. Divide the CADR by the power draw. A purifier that delivers more clean air per watt costs less per unit of cleaning, even if its total draw is higher.
Running one overnight as a white noise machine, or through smoke season? See how much it improves the air in the wildfire smoke calculator, or size one with the CADR calculator.
Questions
How much electricity does an air purifier use?
Most home air purifiers draw between 5 and 100 watts, depending on size and fan speed. Running 24 hours a day, a 30 W purifier uses about 263 kWh a year, roughly $47 at 18¢ per kWh. Efficient models on a low setting can use under 10 W.
Is it cheaper to run an air purifier on low?
Much cheaper. Fan power rises steeply with speed, so halving the speed can cut power use by far more than half. A large purifier on low often cleans as much air as a small one on high while using less electricity and making less noise.
Should I run my air purifier 24/7?
Purifiers are built for continuous use, and the air only stays clean while one runs. Particles return within an hour or two of switching off. For an efficient model, running all day costs a few dollars a month. The bigger running cost is usually filters.
How do I find my purifier’s wattage?
Check the label on the back or bottom, or the manual. Labels usually list the maximum draw on the highest speed. For the real number at the speed you use, a plug-in power meter reads it directly.
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