Large rooms need large room air purifiers.
Large rooms can accumulate large amounts of air pollutants. You could put 2 or more small air purifier in a big room, and remove dust, pollen, smoke, and other air pollutants.
Better still, however, is to do the most obvious thing:
Get a big air purifier for a big room. A 500+ sq ft room does need an air purifier with a 500+ sq ft recommended coverage area (preferably with AHAM Verifide seal).
We will cover the best 7 large room air purifiers below.
First of all, a personal insight: It’s quite a pleasure to review big air purifier for large rooms. The reason is simple. When it comes to large room air purifiers, every air purifier brand brings its A-game.
Big air purifiers usually have the best filtration system (often H13 HEPA filters), highest CADR ratings, and higher maximal airflows. Many of these large air purifiers are the best brand models overall.
Example: Alen BreatheSmart 75i – the best large room air purifier with 1000+ sq ft (2 ACH) coverage area – is the best Alen model. Coway Airmega 400 Smart is the best Coway air purifier; even better than the legendary Coway AP-1512HH.
Before we look at the best big air purifiers, a note about coverage areas. Different big room air purifiers might have different recommended coverage areas. To properly compare them, LearnMetrics recalculated all the coverage areas based on either 2 air changes per hour (2 ACH) and 5 air changes per hour (5 ACH).
That’s how you can easily compare the large room coverage areas of the best large air purifiers head-to-head. You can also properly evaluate the room size; 2 ACH coverage area is standard, 5 ACH is recommended for people inclined to allergies.
What that in mind, let’s look at the list and the following comparison of top-rated large air purifiers. Further on, we will compare coverage areas, CADR ratings, noise levels, and make sure to read the individual reviews of these huge air purifiers before you make a buying decision:
Best Air Purifier For Large Rooms (Comparison)
- Quietest Best Large Room Air Purifier: Alen BreatheSmart 75i
- Most Powerful Large Room Air Purifier With 450 CADR Rating: Blueair Classic 680i
- Best Medical-Grade Air Purifier For Extra Large Rooms: IQAir HealthPro Plus
- High-Performing Large Room Air Purifier: Coway Airmega 400 Smart
- Best Large Room Air Purifier For Pets With 5-Stage Filtration System: Hathaspace Smart 2.0
- New NASA-Level Tech Air Purifier For Larger Rooms: Molekule Air PRO
- Cheapest HEPA Large Room Air Purifier: Honeywell HPA300
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Let’s have a look at some of the vital metrics of the best large room air purifiers:
Coverage Area Of Large Air Purifiers
The whole point of large room air cleaners is that they have a large coverage area.
The two most important factors that determine the coverage area are the CADR rating and max. airflow.
CADR rating (Clean Air Delivery Rate) is an AHAM verified metrics that tells us how well does a particular air purifier captures air pollutants, such as dust, smoke, and pollen.
An average air purifier will have a CADR rating of about 200. Large room air purifiers should have an above-average 200+ CADR rating in order to be able to handle large amounts of polluted indoor air.
If you look at the comparison table, you see that all big room air purifiers have 200+ CADR ratings (the exception is Molekule Air which doesn’t share CADR ratings). In fact, most of them have a 300+ CADR rating.
CADR of 350 is optimum for large rooms. The most powerful unit – Blueair Classic 680i – has an exceptional 450 CADR rating.
On the low end, we have Hathaspace Smart 2.0 with a 265 CADR rating. You can also see that Hathaspace has a lower coverage area. However, its prime advantage is the thorough 5-stage filtration system.
Maximal airflow is the airflow an air purifier can create on its highest fan speed setting. Average max. airflow for an average air purifier is about 200 CFM. It only makes sense that the best large room air purifiers have a high 300+ CFM max. airflow.
Not all air purifier brands share this information in the respective specification sheets. The Blueair Classic 680i has the most powerful fan that can generate an enormous 650 CFM airflow.
However, the well-balanced CADR-to-ACH ratio is more important than absolute numbers. You can check the Alen BreatheSmart 75i review here to see how a well-balanced ratio looks like (it’s also an important factor that makes the 75i model the best air purifier in 2021).
The important part then calculating the coverage area of large air cleaners is the number of air changes per hour.
To properly compare the coverage sizes of large air purifiers, we need to put them under the common denominator as far as ACH is concerned.
Coverage Area At 2 ACH (Standard Coverage)
2 air changes per hour (2 ACH) simple means a large air purifier will be able to completely change the air in a big room every 30 minutes. Hence, 2-times per hour.
Applying this, you can see that most large air purifiers have a coverage area between 1,000 and 2,000 sq ft. That means you can use them for 1 large room, and 1 or more adjacent smaller rooms with ease.
There are 2 exceptions to this rule. IQAir HealthPro Plus is the extra-large room air purifier with a gigantic 2813 sq ft coverage area.
On the other hand, the Hathaspace Smart 2.0 has a coverage area of 750 sq ft at 2 ACH.
2 ACH is the standard number of air changes per hour for an air purifier. However, most experts do recommend more than 2 ACH. For example, people who tend to get a lot of allergies, are advised to use the 5 ACH calculation.
You can read more about how to use the CFM formula to calculate ACH here.
Coverage Area At 5 ACH (Intense Purification)
At 5 ACH, a large room air purifier will change all the air in a room every 12 minutes. Of course, the room size for such an intensive air purification is thus reduced from 1,000 sq ft to 2,000 sq ft at 2 ACH.
At this intense 5 ACH purification, the coverage area of large air purifiers is between 300 and 1,000 sq ft.
Realistically, you will get the most benefit by following the 5 ACH coverage area recommendations.
We see that the best unit – Alen BreatheSmart 75i – can significantly improve air quality in rooms of about 520 sq ft. ‘About’ 520 sq ft means that it will do exceptionally well in 350 sq ft to 700 sq ft large rooms. It’s quite a useful interval to have in mind when checking the coverage areas on big air purifiers.
Of course, the extra-large room air purifier by IQAir has a 1,000+ sq ft coverage area even at 5 ACH.
A Word About H13 Filters
As previously stated, large room air purifiers are exceptionally well-engineered because all air purifier brands bring their A-game when designing them.
The most important part are the filters. More than half of all air purifiers on the market use True HEPA filters. That’s why it’s so magnificent to look at the list of the best large room air purifiers. Why?
Because most of them have the advantaged H13 HEPA filters. True HEPA filters can handle 0.3-micron air pollutants very well. By comparison, H13 HEPA filters Alen BreatheSmart use can handle 3-times smaller 0.1-micron air pollutants with increasing efficacy.
HyperHEPA filters employed by IQAir HealthPro Plus can capture particles that are 0.003-micron in size which is just amazing.
In essence, the top-rated large room air purifiers really do have a battle of advanced filtration systems vs. sheer airflow power.
With that in mind, let’s have a look at the top choices for the big room air purifiers:
1. Alen BreatheSmart 75i Review (Quietest Best Large Room Air Purifier)
|Coverage Area (2 ACH):||1300 sq ft|
|Coverage Area (5 ACH):||520 sq ft|
|Max. Airflow:||347 CFM|
|Filters:||75i True HEPA (H13)|
|Noise Levels:||25-49 dB|
Alen BreatheSmart 75i is big but not the biggest. It’s heavy but not too heavy. It has a high price point but it’s not the most expensive unit. It’s powerful but it’s not the most powerful large air purifier. So why is it chosen as the best large room air purifier?
In short: Perfect balance.
If you look at the Alen BreatheSmart 75i specification, you can see how outstandingly well-balanced numbers it has. First of all, it has a big 350 CADR rating with 347 CFM maximal airflow; an almost 1:1 perfect ratio.
It has a coverage area of 1300 sq ft at 2 ACH, and 520 sq ft at 5 ACH. You can pretty much use it in any room between these two square footages. It’s not an extra-large room air purifier; it’s the essence of an air purifier for a large room.
Do you hear what the best part of the Alen BreatheSmart 75i is?
BreatheSmart series by Alen, one of the most distinguished air purifier brands, is designed to be silent. Almost all large room air purifier suffer from 60+ dB noise rates due to higher airflow. Alen BreatheSmart 75i is one of the bigger units that not only managed to reduce the noise levels.
With maximum noise rates of only 49 dB, the Alen BreatheSmart 75i is the quietest large air purifier by far. This is because all BreatheSmart air purifiers are specifically made to be used for bedrooms. Silent operation is a big part of that, as you can read in the comparison of Alen BreatheSmart air purifiers.
To top all that, the 75i model comes with the advanced H13 HEPA filters. Those are especially thorough; they capture more than 99% of particles that are 0.1 microns in diameter. It’s the medical-grade HEPA filtration level.
All in all, Alen BreatheSmart 75i is one of the best air purifiers ever made. The CADR rating, airflow, and coverage area are perfectly synchronized, and the characteristic BreatheSmart silent operation makes the Alen BreatheSmart 75i the best as well as the quietest large room air purifiers:
2. Blueair Classic 680i Review (Most Powerful Large Room Air Purifier With 450 CADR Rating)
|Coverage Area (2 ACH):||1745 sq ft|
|Coverage Area (5 ACH):||698 sq ft|
|Max. Airflow:||650 CFM|
|Filters:||HEPASilent + DualProtection|
|Noise Levels:||32-62 dB|
Blueair Classic 680i is a large air purifier with the best combo of CADR rating and max. airflow. It has one of the highest CADR ratings of 450 and the biggest 650 CFM airflow. This is the most powerful air purifier for large rooms.
Blueair, in general, is one of the most reliable and beloved Swedish brands of air purifiers. The Blueair Classic 680i has pretty much everything you would wish for in a 1,000 sq ft room air purifier. At 2 ACH, has a 1745 sq ft coverage area, and a 698 sq ft coverage area at 5 ACH. That makes it about 40% bigger than the Alen BreatheSmart 75i.
It has air quality sensors that monitor indoor air quality. That’s the requirement for Auto Mode; a setting that automatically adjusts the fan speed setting to capture as much air pollutants as it’s currently required to either maintain or improve air quality.
You can monitor the air quality via the Blueair friend app (you connect it via wi-fi). You can also set timers, control fan speeds, and much more via the app.
Blueair Classic 680i has a thorough filtration system. At the heart is the HEPASilent filter with DualProtection. Honestly, the HEPASilent is an attempt (quite successful) to reduce noise levels. Blueair Classic 680i is the most powerful large room air purifier with 650 CFM; that should create over 65 dB noise level. With the HEPASilent, the highest noise level is 62 dB which is better but not ideal.
In short, Blueair Classic 680i is the reliable most powerful air purifier for large rooms up to 1745 sq ft. It will work best in a 698 sq ft area. Getting a Blueair air purifier is always a good idea:
3. IQAir HealthPro Plus Review (Best Medical-Grade Air Purifier For Extra Large Rooms)
|Coverage Area (5 ACH):||2813 sq ft|
|Coverage Area (2 ACH):||1125 sq ft|
|Max. Airflow:||300 CFM|
|Noise Levels:||32-67 dB|
IQAir HealthPro Plus is the medical colossus of air purifiers. This is not a large room air purifier. With 2813 sq ft (2 ACH) and 1125 sq ft (5 ACH) coverage area, it’s an extra-large air cleaner. In any regard, the IQAir HealthPro Plus is the biggest air purifier for larger rooms.
Its filtration system makes it very medical-friendly. It has special and exclusive HyperHEPA air filters that can filter out incredibly small particles. HEPA filters can capture 0.3-micron particles; HyperHEPA can capture 0.003-micron particles. That’s 100x better than a HEPA filter.
Due to the HyperHEPA filtration system, the IQAir HealthPro Plus is usually rated as the best air purifier for allergies.
The superb filtration, however, does have its disadvantages. The rate of filtration is slower due to finer HEPA filters; CADR rating of 300 and max. the airflow of 300 CFM are a direct result of that. Additionally, the high fan speed setting creates 67 dB of noise; you can hear it very well.
All in all, this is a Swiss-made medical-grade air purifier, especially useful for people who suffer from allergies. If you really need pristine clear air in a large room, the IQAir HealthPro Plus is the best choice with the most thorough HyperHEPA filtration system.
4. Coway Airmega 400 Smart Review (High-Performing Large Room Air Purifier)
|Coverage Area (2 ACH):||1560 sq ft|
|Coverage Area (5 ACH):||624 sq ft|
|Max. Airflow:||340 CFM|
|Filters:||Max2 HEPA with washable prefilter|
|Noise Levels:||22-52 dB|
Coway is a brand that is known for one thing: sheer performance. The Coway Airmega 400 Smart is the best Coway air purifier for large rooms. It outperforms even the always-awarded Coway AP-1512HH Mighty; you can read more about that in the Coway air purifier reviews here.
The performance Coway Airmega 400 Smart displays has to do with two things: powerful 340 CFM airflow and, even more importantly, the Max2 HEPA filters that ramp up the CADR rating to 350. Coway Airmega 400 Smart is the only large area air purifier besides the Alen BreatheSmart 75i that has a bigger CADR rating than the airflow.
In translation, that means it’s exceptionally efficient at removing air pollutants such as smoke, pollen, dust in the recommended coverage area. With 1560 sq ft at 2 ACH and 624 sq ft at 5 ACH, the Coway Airmega 400 Smart has an ample coverage area that can cover even the very large rooms.
All Coway air purifiers are well-engineered. You can see that clearly in the large room Coway Airmega 400 Smart air purifier if you check the performance (high airflow, CADR rating) and surprisingly low noise levels.
Coway Airmega 400 Smart is one of the best-performing air purifiers fit for large and even extra-large rooms. It also had user-friendly features like 1,2, 4, and 8-hour timer, Auto Mode, and Energy Star rating. It might land in the #4 place due to the lower coverage area but performance-wise it’s the best.
5. Hathaspace Smart 2.0 Review (Best Large Room Air Purifier For Pets With 5-Stage Filtration System)
|Coverage Area (2 ACH):||750 sq ft|
|Coverage Area (5 ACH):||300 sq ft|
|Filters:||5-stage with True HEPA|
|Noise Levels:||30-60 dB|
Hathaspace 2.0 is the smallest large room air purifier with 750 sq ft coverage at 2 ACH. It’s made by a lesser-known brand Hathaspace (you can read more about Hathaspace air purifier here) but is quickly gaining a reputation as the best large room pet air purifier.
The main pet-friendliness factor is the 5-stage filtration system. If you look at the filter-by-filter, it’s not even that extraordinary; pre-filter, activated carbon filter, and HEPA filter are all there. Here are the two additional filters that make the Hathaspace HSP002 large air purifier special:
- Secondary pre-filter, designed to capture pet dander, and further protect the precious HEPA filter.
- Cold catalyst filter that targets VOCs and harmful chemicals found in household cleaning products.
The secondary pre-filter, made out of polypropylene fibers is important if you have a cat or a dog in a large room. Have 2 pre-filters instead of a single one will thoroughly protect the HEPA filter by capturing all large air pollutants that come from pets.
The CADR rating of 265, however, is a little low for a large room air purifier. Because it’s a bit smaller than the very large room air purifier, it also has a more budget-friendly below $500 price.
All in all, if you have pets that spend a lot of time in a larger room, the Hathaspace Smart 2.0 is the best air cleaner that will capture all that pet hair, lint, fluff, and dander.
6. Molekule Air PRO Review (New NASA-Level Tech Air Purifier For Larger Rooms)
|Coverage Area (5 ACH):||1000 sq ft|
|Coverage Area (2 ACH):||400 sq ft|
|Noise Levels:||33-64 dB|
Among all the large room air purifiers, the Molekule Air PRO is the most exceptional one. If you check the review of Molekule air purifier, you will find out exactly what makes it so special:
The NASA-level PECO filtration technology. Instead of using the standard HEPA-based filtration system, all Molekule air purifiers use PECO filters that use photoelectric catalytic oxidation to destroy air pollutants. The additional benefit of that is the often disputed inactivation or destruction of certain bacteria and viruses.
Molekule Air PRO is the biggest Molekule air purifier with a 1000 sq ft coverage area at 2 ACH. Due to the novel filtration system, we don’t have max. airflow or CADR rating specifications.
However, we do have noise levels. The minimum is 33 dB and the maximum is 64 dB; not ideal, obviously.
Despite that, however, the Molekule Air PRO is definitely the most innovative large room air purifier with the cutting-edge PECO filtration system, an upgrade from the PCO system.
On top of that, it has a very aesthetically pleasing design:
8. Honeywell HPA300 Review (Cheapest HEPA Large Room Air Purifier)
|Coverage Area (2 ACH):||1163 sq ft|
|Coverage Area (5 ACH):||465 sq ft|
|Noise Levels:||Up to 55 dB|
Honeywell HPA300 is the best Honeywell air purifier. However, compared to the top-rated large room air purifiers, the Honeywell HPA300 is painfully ordinary.
It has a decent 1163 sq ft coverage area at 2 ACH and 465 sq ft at 5 ACH, thanks to the 320 CADR rating. But that’s pretty much it.
Honeywell HPA300 uses an ordinary True Hepa filter, pre-filter, and activated carbon filter. It does a decent job in a large room but it’s nothing to brag about.
Prett much the only advantage Honeywell HPA300 has over other large air purifier is the price. High-performing large room air purifier can quickly cost more than $700. Honeywell has a below $300 price for its HPA300 model. It’s not the best but at least it’s the cheapest air purifier for big rooms:
Large Room Air Purifiers FAQ
Let’s answer a few question about air cleaners and big rooms:
What Is The Best Large Room Air Purifier?
As we have seen, there are many valid choices with the best one being the Alen BreatheSmart 75i. It’s a perfectly balanced air purifier, specifically designed for large bedrooms.
It has powerful airflow, a high CADR rating, and the quietest operation (below 50 dB). You might find bigger air purifiers or even ones with better filtration systems, but the 75i model is the very embodiment of the specification you want in a large room air purifier.
Can An Air Purifier Be Too Big For A Room?
This is a common concern. An air purifier can be too big for a room. However, what really matters are the consequences of that: there are practically none.
Even if you big a very large air purifier that would be overkill for the room you put it in, it will do you no harm.
Of course, the unit price, replacement filters, and electricity bills will be higher, which is unpleasant but there are no documented real problems that would occur if you have an oversized air purifier in a room.
Will A Small Air Purifier Work In A Large Room?
Doubtfully. If you’ve miscalculated the size of an air purifier and bought one that’s too small, it will not properly increase the indoor air quality in that room.
Putting a small air purifier in a large room is better than nothing, obviously, but’s a job half done. The smaller air purifier will have a shorter lifespan, the replacement filters will have to be changed more frequently, and so on.
The smartest thing to do is to buy a large air purifier for a large room. Simple.
If you have any other questions, you can pose them in the comments below.