700 m³/h Sounds Powerful. Until You Put It in the Wrong Room.

A number like 700 m³/h looks impressive on an air-purifier specification sheet.

And it should.

Clean Air Delivery Rate, or CADR, is one of the most useful performance figures buyers have when comparing air purifiers.

But there is a problem.

A CADR number does not tell us, by itself, whether the purifier is right for:

a 20 m² bedroom,

a 40 m² living room,

a 70 m² open-plan apartment,

or a large hotel suite.

The same purifier can look extremely powerful in one room and surprisingly ordinary in another.

That is why, when buyers ask us at Minfu whether 698.3 m³/h is “high enough,” we normally do not answer with another specification.

We ask:

How large is the room—and how much air is actually inside it?

That second part is where many air-purifier comparisons go wrong.

CADR Is a Cleaning Rate, Not a Room Size

CADR describes the amount of cleaned air an air purifier can effectively deliver over a given period.

In metric specifications, it is commonly expressed in:

m³/h — cubic metres per hour

In the U.S., it is often expressed in:

CFM — cubic feet per minute

A higher CADR generally means the purifier can remove the relevant particles from the air faster than a lower-CADR purifier under comparable test conditions. AHAM describes CADR as the volume of filtered clean air delivered by the air cleaner and uses separate CADRs for pollutants such as smoke, dust and pollen.

That makes CADR extremely useful.

But CADR is still a rate.

It does not automatically mean:

700 m³/h = 70 m²

or:

700 m³/h = 100 m².

To understand room suitability, we need another number:

room volume.

Two 40 m² Rooms May Not Be the Same Room

This is one of the easiest things to overlook.

Imagine two rooms.

Both have exactly:

40 m² floor area.

Room A has a 2.5 m ceiling.

Room B has a 4 m ceiling.

Their floor area is identical.

Their air volume is not.

Room A

40 × 2.5 = 100 m³

Room B

40 × 4 = 160 m³

The second room contains 60% more air.

So if we put exactly the same purifier in both rooms, it cannot process the entire air volume at the same equivalent rate.

This is why EPA guidance specifically tells buyers to consider higher ceilings when sizing portable air cleaners; its room-size guidance assumes an 8-foot ceiling, and higher ceilings may require a larger-rated unit.

Floor area is convenient.

Air volume is what the purifier actually has to deal with.

This Is Where Air Changes per Hour Become Useful

A useful way to connect CADR with room size is to look at equivalent air changes per hour, or eACH.

The simplified relationship is:

eACH ≈ CADR ÷ Room Volume

when:

• CADR is in m³/h;
• room volume is in m³.

This does not mean the purifier is physically replacing all the room air with outdoor air.

AHAM distinguishes normal building ACH from equivalent ACH produced by filtration. The latter expresses the clean-air contribution of the air cleaner. AHAM’s current white paper specifically describes CADR, Suggested Room Size and eACH as related metrics for evaluating room-air-cleaner performance.

For buyers, it gives us a much better way of understanding what one CADR number means in different spaces.

What Does 700 m³/h Actually Look Like?

For simplicity, suppose we have a purifier delivering approximately:

700 m³/h CADR

and all rooms below have a 2.5 m ceiling.

The simple CADR-based calculation looks like this:

Same purifier.

Same 700 m³/h.

Completely different clean-air delivery relative to the room volume.

That is why asking:

“How many square metres does 700 m³/h cover?”

without defining anything else is an incomplete question.

The more useful question is:

At what room volume and desired clean-air rate?

Why “Coverage Area” Numbers Can Look So Different

This explains something B2B buyers often notice.

Two competing air purifiers may have very similar CADR figures but completely different claims on their product pages.

One might say:

Coverage: 40 m²

Another:

Coverage: 70 m²

Another:

Coverage: 100 m²

At first glance, someone must be wrong.

Not necessarily.

The manufacturers may be using different assumptions for:

• ceiling height;
• required eACH;
• pollutant type;
• test method;
• target removal level;
• operating mode;
• or marketing definition of “coverage.”

AHAM’s 2026 white paper addresses exactly this problem. Its Verifide Suggested Room Size is based on 4.8 equivalent air changes per hour and a defined smoke-particle removal model. AHAM also notes that other room-size claims in the market may use different ACH assumptions, which can produce substantially different apparent coverage areas.

This is one reason we think distributors should be careful with a huge:

“COVERS 1,500 SQ FT!”

printed on a carton.

The number is only useful when you understand what performance level that coverage represents.

AHAM’s 2/3 Rule Is Useful — But Do Not Apply It Blindly

For U.S. buyers, AHAM offers a simple rule of thumb.

For a standard room, it recommends a smoke CADR of at least approximately two-thirds of the room area in square feet.

So a 120 ft² room would call for a smoke CADR of about 80 CFM.

For higher-than-8-foot ceilings, AHAM advises selecting a purifier rated for a larger room.

That is useful when comparing AHAM-style smoke CADR results.

But we would not recommend taking a CADR from an unrelated test method, converting the units and automatically claiming an AHAM room size.

For OEM projects, the test method matters.

Before turning:

CADR → Coverage Area

into packaging artwork, buyers should know:

Which pollutant was tested?

Which standard was used?

Which operating mode?

Which CADR value is being referenced?

That is particularly important when products will be sold across different regulatory and retail markets.

Particle CADR and Gas CADR Are Not the Same Claim

Our current Minfu AI mobile air purifier robot platform lists:

698.3 m³/h Particle CADR

and:

560 m³/h Gas CADR

along with a published 40 m² coverage area.

Those two CADR values should not be treated as interchangeable.

Particle CADR evaluates removal performance for the applicable particulate test contaminant.

Gas purification involves a different pollutant-removal mechanism and test context.

So we would not take:

698.3 m³/h particle CADR

and use it as automatic proof of the same performance against every gaseous pollutant.

Likewise, we would not take:

560 m³/h gas CADR

and treat it as though it were a particle-room-sizing figure.

This sounds obvious when written down.

It becomes surprisingly easy to blur the two once a sales brochure starts shortening every specification into a few icons.

So Why Does Minfu Currently State 40 m²?

Our published platform specification currently lists:

Coverage Area: 40 m²

with a particle CADR of:

698.3 m³/h.

If we use a simple example with a 2.5 m ceiling:

40 m² × 2.5 m = 100 m³

698.3 ÷ 100 ≈ 7.0 equivalent clean-air changes per hour

At a 3 m ceiling:

40 × 3 = 120 m³

698.3 ÷ 120 ≈ 5.8 eACH

That gives buyers much more context than simply seeing:

40 m².

But we need to be careful about what this calculation means.

It is a simplified CADR-to-volume illustration, not a replacement for the applicable product test report or a guarantee of a specific pollutant concentration in every real room.

Actual spaces include:

• infiltration;
• doors opening;
• furniture;
• poor air mixing;
• ongoing pollutant sources;
• different ceiling structures;
• HVAC airflow;
• and different purifier placement.

This is why our final external performance claims should remain aligned with confirmed test conditions and the applicable market standard rather than being created from a calculator alone.

High CADR Can Still Be Wasted by Bad Placement

A powerful purifier still needs access to the air.

Put the machine:

behind a sofa,

inside a narrow corner,

against curtains,

beneath furniture,

or somewhere with badly restricted intake and outlet airflow,

and the room may not benefit from its rated capability as effectively as expected.

AHAM specifically advises giving the purifier room to breathe and warns that placing a unit against a wall or in a corner can restrict airflow and reduce performance.

This introduces another gap between:

laboratory CADR

and:

real-world cleaning speed.

The laboratory needs repeatability.

A customer’s home rarely gives us perfect geometry.

Open-Plan Homes Make “Room Size” Even More Complicated

Now consider a modern apartment.

There is no closed 40 m² living room.

Instead there is:

living room + kitchen + dining area + hallway

all connected.

The visible living zone may be 35 m², but the purifier is exchanging air with a much larger connected space.

EPA guidance recommends considering the entire area served when selecting a portable purifier for an open floor plan.

That changes the math quickly.

A purifier that feels oversized in a closed bedroom may feel much less oversized once the doors disappear.

For B2B buyers, this matters because retail packaging often shows an ideal living room while customers actually install the machine in very different layouts.

A realistic product recommendation should survive that difference.

Can One High-CADR Purifier Clean an Entire Home?

This is where things become especially interesting for a mobile air purifier.

A stationary purifier with 700 m³/h CADR is still operating from one physical location.

If doors are closed, airflow between rooms is limited.

If the floor plan is divided, air from a distant bedroom does not instantly arrive at the living-room purifier.

So:

high CADR does not automatically equal whole-home purification.

EPA guidance even notes that if a space is larger than one purifier can appropriately serve, multiple air cleaners may be considered.

Mobility changes the problem.

Instead of asking one fixed purifier to pull air from every room toward itself, a mobile platform can potentially bring its purification system closer to different rooms or zones.

That does not magically multiply CADR.

But it changes where the available CADR is being applied.

This is one of the reasons our previous article on what the AI in an AI air purifier is actually doing focused so much on location and decision-making.

For a stationary purifier:

Sensor → adjust airflow.

For a mobile purifier:

Sensor + map → potentially change airflow and location.

That distinction deserves its own discussion, and we will cover the multi-room question separately rather than pretending mobility automatically means unlimited coverage.

Bigger Is Not Always Better Either

There is another mistake on the opposite side.

If high CADR is good, why not simply buy the largest purifier possible?

Sometimes that makes sense.

But B2B product selection also involves:

• product size;
• fan noise;
• motor cost;
• filter size;
• energy consumption;
• retail price;
• shipping volume;
• and physical design.

A 700 m³/h platform may be attractive for a large-room or premium SKU.

It may be unnecessary for a small bedroom product where low noise, compact dimensions and lower price matter more.

This is why we do not think there is one universally “best” CADR.

There is a right CADR for the product position.

For a distributor, the better question is:

Which room size, price range and usage scenario is this SKU supposed to win?

Then choose the performance architecture around that.

Not the other way around.

What Buyers Should Ask When Comparing Coverage Claims

If two suppliers send us air-purifier quotations and one says:

Coverage: 40 m²

while another says:

Coverage: 80 m²,

we would not compare the numbers immediately.

We would ask:

What is the tested CADR?

Not just motor airflow.

Not fan free-air volume.

The actual relevant clean-air delivery figure.

What pollutant does the CADR refer to?

Particle?

Smoke?

Dust?

Pollen?

Gas?

Which test method or standard was used?

This is especially important when comparing suppliers from different markets.

What room-height assumption is behind the coverage claim?

40 m² at 2.4 m and 40 m² at 4 m are very different loads.

What eACH or cleaning objective is assumed?

A huge room-size claim may simply mean fewer equivalent clean-air changes per hour.

At what fan level?

Maximum mode?

Normal mode?

Sleep mode?

A maximum CADR claim tells buyers little about quiet-use performance unless those operating modes are also understood.

Is the coverage claim from testing or calculation?

Both can be useful.

They are not the same evidence.

A Simple Buyer Calculation Is Often Enough to Spot Problems

For an early-stage comparison, we like a very simple check.

Step 1 — Calculate room volume

Floor area × ceiling height

Example:

50 m² × 2.8 m = 140 m³

Step 2 — Divide CADR by room volume

Suppose:

CADR = 700 m³/h

700 ÷ 140 = 5 eACH

Now we have something useful to compare.

Another supplier claims:

700 m³/h

but markets it for:

100 m² × 2.8 m = 280 m³.

700 ÷ 280 = 2.5 eACH

Same CADR.

Very different room-size story.

That does not automatically prove one claim is unacceptable.

But it immediately tells the buyer:

These two brands are defining “coverage” differently.

Now we know what to ask next.

The Lab Number Still Needs a Real Room

This is why CADR testing and real-use evaluation should complement each other.

A controlled chamber tells us whether the purifier’s cleaning rate is repeatable.

A real-room test tells us whether the final product architecture works in the kind of environment customers actually have.

For an OEM sample, we would therefore want to look at both.

In the lab:

• verify purification performance;
• confirm operating mode;
• verify noise;
• verify sensor response.

Then in realistic spaces:

• standard bedroom;
• living room;
• open-plan space;
• doorway between zones;
• different ceiling heights.

For a mobile platform we would add:

• room-to-room navigation;
• dwell time;
• air-quality response;
• battery consumption;
• automatic recharge;
• and repeated patrol behavior.

The CADR number tells us what the purification system can do.

The space tells us whether the product uses that capability well.

For Mobile Air Purifiers, Coverage May Eventually Need a Better Language

This is an area we think the category will have to improve.

Traditional room-air-cleaner marketing assumes:

one purifier
one location
one defined room.

A mobile purifier does not always operate that way.

It may spend part of its time in:

Room A,

then Room B,

then Room C.

That means buyers eventually need to think about two different questions.

Instantaneous capability

How much clean air can the purifier deliver where it is currently operating?

That is where CADR remains essential.

Service strategy

How does the robot divide its operating time between different rooms?

That depends on:

• sensing;
• navigation;
• room size;
• pollution level;
• battery;
• fan mode;
• and software logic.

We should not confuse those two.

A robot moving through three rooms does not suddenly have three times the CADR.

But the mobility layer may allow one purification platform to serve different zones over time instead of remaining beside one wall.

That is a different value proposition.

And it needs to be tested differently.

Our View: Do Not Buy the Biggest Coverage Number

For a distributor, brand or sourcing team, CADR is valuable precisely because it gives us something measurable.

The mistake is converting that useful engineering number into an oversized marketing claim.

We would rather see:

698.3 m³/h Particle CADR

with a clearly defined product position,

than:

Purifies the entire home!

with no explanation of room volume, test conditions or expected cleaning rate.

The strongest air-purifier specification is not necessarily the biggest number.

It is the number that still makes sense after a buyer asks:

How was it measured?

What room is it meant for?

What happens when the room gets bigger?

If those questions have clear answers, CADR becomes genuinely useful.

If they do not, “coverage area” can become one of the easiest numbers on an air-purifier page to misunderstand.

FAQ

What does CADR mean on an air purifier?

CADR means Clean Air Delivery Rate. It represents the rate at which an air cleaner delivers cleaned air for the applicable pollutant under its test conditions. Higher CADR generally means faster pollutant removal when products are compared using compatible methods.

What CADR do I need for my room size?

It depends on room volume, ceiling height, pollutant type and the desired equivalent clean-air rate. In the U.S., AHAM recommends a smoke CADR of at least about two-thirds of the room area in square feet for standard-height rooms as a practical sizing rule.

Is 700 m³/h CADR good?

700 m³/h is a high clean-air delivery rate for many residential applications, but whether it is appropriate depends on the room volume and target cleaning rate. The same 700 m³/h would provide roughly 7 eACH in a 100 m³ room but only 3.5 eACH in a 200 m³ room.

How do I calculate air purifier room size from CADR?

A useful first step is to calculate room volume:

floor area × ceiling height

Then calculate a simple CADR-based equivalent air-change rate:

CADR ÷ room volume

This is useful for comparison but should not replace the relevant certification method or product test report.

Does a higher CADR always mean a better air purifier?

Not necessarily. Higher CADR means faster clean-air delivery under the relevant test conditions, but buyers should also consider filtration, noise, energy use, filter resistance, placement, room layout and the product’s target application.

Does an air purifier with high CADR clean multiple rooms?

Not automatically. Walls, doors and airflow between rooms affect how effectively a stationary purifier can serve separate spaces. Mobility may allow a robotic purifier to operate in different zones, but it does not increase the purifier’s underlying CADR.

Work With Minfu

Looking for a differentiated smart air-care product for your market?

Minfu provides one-stop OEM/ODM manufacturing, product development, customization, quality control and mass-production support for brands, importers, distributors and retailers worldwide.

Our AI mobile air purifier platform combines high clean-air delivery, H13 HEPA filtration, air-quality sensing, autonomous navigation and smart control for brands exploring the next generation of air-care products.

Website: minfutech.com
Email: info@minfutech.com
WhatsApp / Phone: +86 13760255781

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