How much does it cost to run an air purifier 24/7?

For most HEPA units it is only a few dollars a month. At the 2026 U.S. average electricity rate, a typical purifier on a medium speed, around 50 watts, costs about $7 a month run continuously, roughly $80 a year. A large unit on high can reach $14 to $20 a month while you run it that hard.

Do air purifiers use a lot of electricity?

No, not compared with most home appliances. Across the units we have scored, standard-speed power draw runs from 8 to 146 watts, about the range of a light bulb up to a small TV. Fan speed is what moves the number, so running a lower speed when the air is only mildly smoky keeps the cost down.

How much faster do air purifier filters wear out in wildfire smoke?

Much faster. The EPA and American Lung Association note that heavy smoke can force a replacement at 50 to 75 percent of a filter's rated life, and sometimes more than once in a season. A filter rated for a year might need changing in six to nine months of serious smoke, and the carbon layer loads even sooner.

Is it cheaper to run one purifier in a clean room or several around the house?

One right-sized purifier in a single cleaner-air room is usually cheaper and more effective than trying to clean the whole house. You concentrate the filtration where you actually spend time, run fewer units, and buy fewer replacement filters.

Air guide

How Much Does It Cost to Run a HEPA Air Purifier 24/7?

Running a HEPA purifier around the clock in smoke season costs less in electricity than most people fear. The real cost is filters, which wildfire smoke loads far faster.

The short version: power is cheap, filters are the real cost

When the smoke rolls in and the guidance says run your air purifier around the clock, the natural next worry is the electric bill. Here is the reassuring part: for most units, running a HEPA purifier 24/7 costs only a few dollars a month in electricity. The cost that actually adds up during a smoke season is filters, because wildfire smoke loads them far faster than everyday use.

Below is what each piece really costs, using the power-draw figures from the air purifiers we have scored and the current U.S. electricity rate, plus what the EPA and the American Lung Association say about running a purifier continuously.

What the electricity actually costs

An air purifier's running cost comes down to one number: how many watts it pulls. Across the air purifiers we have scored, disclosed power draw at a standard speed runs from 8 watts to 146 watts, with most true-HEPA units landing between about 25 and 65 watts. True HEPA just means a filter that meets the strict particle-capture grade, the kind you want for smoke.

The math is simple: watts divided by 1,000, times 24 hours, times 30 days, times your electricity rate. At the U.S. residential average of 18.83 cents per kilowatt-hour (the April 2026 figure from the EIA), here is how a full month of nonstop running shakes out.

On a low or sleep setting, around 10 watts, you are looking at roughly $1 to $2 a month. A typical unit on a medium speed, around 50 watts, runs about $7 a month, or close to $80 over a full year of continuous use. A large purifier pushed to high during heavy smoke, 100 watts or more, can reach $14 to $20 a month for as long as you run it that hard. Even at the top of that range, the power is not the part of this that hurts.

Why filters are the bigger number in smoke season

Here is where a smoke season is different from normal life. A HEPA filter has a finite amount of capacity, and wildfire smoke is dense with fine particles, so it fills that capacity much faster. The EPA and the American Lung Association both note that during heavy smoke, filters can need replacing at 50 to 75 percent of their rated life, and sometimes more than once in a bad season.

In plain terms: a HEPA filter rated to last a year might need swapping in six to nine months if you run it through a serious smoke stretch, and the carbon layer that handles the smell loads even faster than that. Replacement HEPA-and-carbon sets vary a lot by model, from around $30 for a small unit to well over $100 for a large one. You can find the real replacement cost and yearly filter figure for each unit we score in our filters section.

So the honest budget for a smoke season is a few dollars a month in electricity plus one, or in a bad year two, filter changes. For most households that is a modest total for cleaner indoor air while the outdoor air is hazardous.

Should you run it around the clock? What the guidance says

Yes, during an active smoke event. The EPA advises setting up a cleaner-air room and running a portable HEPA cleaner continuously when smoke is in the air, and the American Lung Association notes that a well-matched HEPA cleaner can cut indoor fine-particle levels substantially. Continuous is the point: particles keep infiltrating, so a purifier that is switched off is not protecting anyone.

A rough trigger to remember: once the Air Quality Index reaches 150, the unhealthy-for-sensitive-groups level, that is the cue to keep the purifier running and stay indoors. The higher the AQI climbs, the more the continuous run matters.

How to keep the running cost down

A few habits keep both numbers in check. Right-size the unit to the room so it can clean the air at a lower, cheaper speed instead of always running flat out; our guide on matching a purifier to a room by its clean-air delivery rate walks through the sizing. Run a moderate speed when the air is only mildly smoky and save the high setting for the peaks, since watts climb steeply with fan speed.

Protect the expensive filter by keeping the cheap pre-filter clean: vacuum or rinse it on schedule so grit does not choke the HEPA early. Concentrate on one cleaner-air room rather than trying to purify the whole house at once, which is both more effective and cheaper. And during smoke, back the purifier up with a MERV 13 or higher furnace filter in your HVAC so the two systems share the load.

The bottom line

Running a HEPA air purifier 24/7 through wildfire season costs most households roughly $1 to $20 a month in electricity, depending on the unit and the fan speed, plus the filters that smoke wears out faster than usual. The power is the small, predictable part. The filters are the cost that scales with how bad the season gets, and they are the number worth planning for.

FAQ

How much does it cost to run an air purifier 24/7?: For most HEPA units it is only a few dollars a month. At the 2026 U.S. average electricity rate, a typical purifier on a medium speed, around 50 watts, costs about $7 a month run continuously, roughly $80 a year. A large unit on high can reach $14 to $20 a month while you run it that hard.
Do air purifiers use a lot of electricity?: No, not compared with most home appliances. Across the units we have scored, standard-speed power draw runs from 8 to 146 watts, about the range of a light bulb up to a small TV. Fan speed is what moves the number, so running a lower speed when the air is only mildly smoky keeps the cost down.
How much faster do air purifier filters wear out in wildfire smoke?: Much faster. The EPA and American Lung Association note that heavy smoke can force a replacement at 50 to 75 percent of a filter's rated life, and sometimes more than once in a season. A filter rated for a year might need changing in six to nine months of serious smoke, and the carbon layer loads even sooner.
Is it cheaper to run one purifier in a clean room or several around the house?: One right-sized purifier in a single cleaner-air room is usually cheaper and more effective than trying to clean the whole house. You concentrate the filtration where you actually spend time, run fewer units, and buy fewer replacement filters.

Sources

Browse air purifier scores or water filter scores.