CADR, Filters & Cost to Run

What air purifier filters actually cost

The recurring cost nobody factors in at purchase, worked out with the assumptions on the page so you can change them.

Published September 2, 2026

Last verified September 2, 2026

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The short answer

Replacement filters typically cost $30 to $120 a year depending on the machine and household. Manufacturer intervals assume general household use; a shedding pet shortens them materially, and a washable pre-filter is the single most effective way to protect the interval.

Purchase price gets all the attention and filters are where the money actually goes over a machine’s life. This page shows the arithmetic rather than the conclusion, so you can substitute your own numbers.

What we could source, and what we could not

Filter pricing is poorly published in this category. Some manufacturers give a price and no interval, some an interval and no price, most neither in one place. Rather than estimate, this table shows what each manufacturer actually publishes.

Published filter interval and price, by manufacturer
Unit	Published interval	Published price	Annual filter cost
Alen BreatheSmart 75i	12–15 months (24/7)	Not published	Not computable
Coway AP-1512HH	Carbon 6 mo, HEPA 12 mo	Not published	Not computable
LEVOIT Core 400S	Not published	$49.99 (3-stage)	Not computable
LEVOIT Core 300S	Not published	$29.99–$39.99	Not computable
GermGuardian AC4825	Not published	$39.99 (FLT4825)	Not computable
Honeywell HPA4300	Not published	Not published	Not computable
Winix 5500-2	Not published	Not published	Not computable

This table is mostly empty and that is the finding. If a manufacturer published both figures we would compute the annual cost; we are not going to produce a number by assuming an interval nobody stated. Prices shown were listed on 2026-09-02 and change — check the current figure before buying.

A worked example, with the assumptions visible

Where both numbers exist you can do this yourself. Take the GermGuardian FLT4825 at its listed $40:

Annual filter cost at different intervals — GermGuardian FLT4825
Assumed interval	Filters per year	Annual cost
6 months (heavy pet household)	2.0	$80
8 months	1.5	$60
12 months (typical claim)	1.0	$40

The intervals in the left column are our assumptions, labeled as such — GermGuardian does not publish one that we could find. The arithmetic is real; the inputs on the left are scenarios.

What actually shortens a filter’s life

Pet hair, above everything. It loads pleats fast and it is the reason manufacturer intervals set for general households are optimistic in a shedding one.
Running at high speed continuously. More air through the media is more loading.
Litter dust, particularly clay litters.
Construction or renovation dust, which can consume a filter in weeks.
Not cleaning the pre-filter. The one on this list you fully control. Washable pre-filters and what they save.

Carbon runs out faster, and for a different reason

A HEPA filter fails by clogging. A carbon filter fails by saturating — every adsorbed odor molecule occupies a site permanently, so capacity depletes with use rather than with airflow resistance. That is why manufacturers who separate the two stages publish a shorter interval for carbon, as Coway does at six months against a year.

It also explains a common experience: a machine that seemed to handle the smell for a few months and then stopped. How carbon capacity works.

Quick picks

Ranked on certified Clean Air Delivery Rate against the room size each unit is certified for, then on what it costs to run. Tap any row for the full write-up.

#	Product	Best for	Certified CADR	Price
1	No photo Longest published interval Alen BreatheSmart 75i 12-15 months at 24/7 operation — the longest documented here.	Very large rooms, long filter intervals	370CFM smoke ENERGY STAR verified	Check price on Amazon
2	No photo Best documented schedule Coway Airmega Mighty AP-1512HH Six months for deodorization, a year for HEPA, plus a washable pre-filter.	The popular default, unverified	233CFM smoke Manufacturer-claimed	Check price on Amazon
3	No photo Cheapest to run overall Honeywell InSight HPA4300 31 watts means the electricity half of the bill is minimal.	True HEPA on the lowest power draw	229CFM smoke AHAM VERIFIDE	Check price on Amazon

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The electricity half of the bill is far better documented, because both registers publish certified annual energy use. Running cost, computed for every unit.

Common questions

How much do air purifier filters cost per year?

Typically $30 to $120 a year depending on the machine and how hard the household works it. Where a manufacturer publishes both an interval and a price we show the sum; where they publish only one, or neither, this page says so rather than filling the gap with an estimate.

Do I have to use the manufacturer's filters?

Third-party filters are widely available and usually cheaper. The honest position is that we have not tested any of them and cannot tell you how their media compares — and a machine’s certified CADR was measured with the manufacturer’s filter in it, so a substitute is outside the certification.

How do I know when to change the filter?

Follow the indicator if the machine has one, but check the filter visibly too — indicators are usually timers rather than sensors, and a timer knows nothing about your shedding dog. A visibly gray, matted filter is due regardless of what the light says.

Sources

Figures were read on the dates shown against each source. If one has changed, or if we have got something wrong, tell us and we will correct the page.