What is CADR and why is it the only data I would look at when choosing an allergy device?

Spring brings out many things and some are not pleasant at all. Allergies to pollen and many other particles attack us and can give us a hard time. Of everything we can buy to combat them at home, the most effective and useful is, without a doubt, purchasing a air purifier. But, How to choose the most suitable one for your home?

That is the question I have been asking myself in recent days, since all the purifiers I have seen have a gibberish of figures and data that, paradoxically, can confuse more than help us choose. After doing a little research, it is clear to me that, if I have to focus on something, it would be in the CADR. I’ll explain why.

What is CADR and why does it matter so much?

If we enter a store like Amazon and look for any air purifier (like this one from Philipsfor example), right from the start we are going to be inundated with a lot of information. Perhaps what may catch our attention most at first is that it is capable of eliminating 99.97% of the particles in the air, a very high figure. What’s happening? We will find this in most purifiers and it is not the most important thing. That’s where the CADR comes in.

The CADR (clean Air Delivery Rate or Clean Air Delivery Rate in Spanish) is a unit of measurement that tells us, in a few words, the amount of filtered air that a purifier can deliver. A purifier that has the best filter on the market is fine, but is it any good if it is not capable of moving air and filtering it fast enough? Because if you don’t, the pollen or dust particles will end up settling on the furniture and will not be filtered.

The CADR has a numerical value that is calculated with two aspects: how many particles the filter is capable of trapping and how much air the purifier is able to move through said filter. No matter how good the filter is, it is equally important that the purifier is able to move through it, since otherwise it will not trap dust or pollen particles well and they will continue to swarm around our room. Bad thing for our allergies.

Small note that must be taken into account. The CADR is not just a single value, but there are three. This happens because purifiers have a CADR for pollen, but also for dust and smoke. This is important, since what we should focus on is pollen. The others are more secondary.

Falling short of CADR is always a bad idea

If we go back to the Philips purifier above, we can see how it is, in theory, ideal for rooms up to 44 square meters in less than 17 minutes. Now, you have to read the fine print on the device’s own page on Amazon:

It is a theoretical one-time cleaning time calculated by dividing your CADR of 170 cubic meters/hour by the room size of 48 square meters (assuming the room is 20 meters in area and 2.4 meters in height).

Why do I say this? Because although the description of a purifier indicates that it is optimal for a room of a certain size, they are always references taken under certain conditions. that may not fit with our home. The ideal is to take the CADR of the purifier and make a simple calculation that will not lead to errors.

This calculation is done in three phases that I summarize below:

• First, we need to know the cubic meters that has the room where you are going to use the purifier. It is calculated by multiplying length, width and height.
• Second, we need to know how many times you want the purifier to clean the air. The AHAM (Association of Home Appliance Manufacturers) recommends between 5 and 8 per hour.
• To finish, we multiply the volume of the room in cubic meters and the air changes per hour that we want.

Quick example. If you have a room with a volume of 25 cubic meters (because it is 4 meters long, 2.5 meters wide and 2.5 meters high) and you want the purifier to renew the air 5 times per hour, the ideal is that you look for an air purifier with a CADR of at least 125 cubic meters/hour. Be careful here, because many purifiers give you this information in cubic feet per minute (CFM), which is the original AHAM standard.

Now, does it make sense to buy a purifier with a much higher CADR than what you need? If you opt for this scenario, you will have a device that filters the air in your room faster and even without the motor running at full speed all the time (which means less consumption and less noise). The issue here is that a higher CADR also usually means, in the vast majority of cases, paying more for the air purifier. The choice here is up to each user, but with one thing clear: never fall short of CADR.

The good and the bad of both options, face to face

In summary:

👉 Choose a low or medium CADR (up to 400 cubic meters/hour): You want a cheap purifier for a small room and you don’t plan to move it elsewhere.

👉 Choose a high CADR (above 400 cubic meters/hour): you prefer faster purification or plan to place it in a large room.

Recommended models

Low CADR: Xiaomi Smart Air Purifier 4 Lite

This Xiaomi air purifier is one of the best sellers and, with this price it has right now on AliExpress, it is a great value-for-money option for small rooms (its CADR is 120 cubic meters/hour). Its maximum noise level is 61 dB, Their filters last between 6 and 12 months before they need change (the mobile app will notify us when it hits) and has dimensions of 24 x 24 x 52 centimeters.

Intermediate CADR: Philips Series 2200

We go up to 400 cubic meters/hour of CADR with this Philips Series 2200 purifier. This device also calculates the useful life of its filter, but in this case it lasts up to 36 months. It has an automatic mode that calculates the air quality and adjusts its performance based on it, which is useful so that we don’t have to do anything. In addition, it has a 13 dB silent mode that is perfect at night.

High CADR: Bosch Air 6000i

If you are looking to have a purifier for large rooms, this one from Bosch has a CADR of 600 cubic meters/hour. It is the most expensive of the three, but with it you will have a device that you can place in any room of the house and have clean air, regardless of how big it is. It has a night mode that barely emits 25 dB of noise and also has an automatic mode that we can configure or program from our mobile phone.

Do you want to see more models?

If none of these three convince you, you can consult our air purifier buying guide with different models depending on the price range.

Some of the links in this article are affiliated and may provide a benefit to Xataka. In case of non-availability, offers may vary.

Image | sang lee, Lasse JensenXiaomi, Bosch, Philips

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