Choosing The Best Air Purifier

Post date: September 7th, 2011

When it comes to choosing the best air purifier, it can be overwhelming with the great number of models and the different types of air purifier. Where do you start?

In this article, I’ll explain some of the main factors to consider. Choosing the best air purifier for your needs will depend on what your requirements are:

Choosing the Best Air Purifier: Room Size

Probably the first important point in choosing the best air purifier is to make sure that you buy a model which is powerful enough for the room size that you need it for.

The manufacturer of a particular model will almost certainly list the room size that it is suitable for. However, it’s a good idea to check it yourself with an independent source. If you want to double check you should go to the Clean Air Delivery Rate website and check out your model.

You will find that some models aren’t listed. That just means they haven’t been tested by the Association of Home Appliance Manufacturers who own the CADR website. Only manufacturers who sign up for AHAM certification are listed on the CADR website. Some high quality manufacturers like IQAir for example (one of the most efficient models used in medical settings as well as homes) don’t agree with the test procedures of AHAM which they regard as flawed.

The CADR ratings are definitely useful but you should be aware of their possible inadequacies:

The test only looks at particles in the size range of 0.1 to 11 microns.
The test doesn’t look at gas, odor or micro-organism removal from the air.
No test for ozone is done. The information about being within ozone limits on the CADR website is provided voluntarily by the manufacturers.

The CADR website will give you five pieces of information:

CADR for dust
CADR for tobacco smoke
CADR for pollen
Largest room size it’s suitable for
Whether it fulfils the ozone limits.

The CADR figures are expressed in units of cubic feet volume of clean air produced per minute. So, the higher the numbers the better. The room size it’s suitable for is then found by multiplying the CADR number by 1.5. Because of the nature of the testing done by AHAM, the maximum possible CADR figures are 450 for pollen and tobacco smoke and 400 for dust.

These CADR numbers are based on rooms with a ceiling height of 8 feet and a 5 air changes per hour setting. So, if you have a higher ceiling, you need a model for a larger sized room than your actual size room. A good estimate is to add 10% to the square footage for each foot above 8 feet in room height.

The room size specified by CADR is based upon a model’s fastest fan speed and you should get a model which at the very least has your room size or bigger specified. There is a lot to be said for getting a model for a larger room size so that when you have it set to low fan speed, it is still doing a better job of cleaning.

Choosing The Best Air Purifier:

Types of Air Purifier And The Type Of Pollutants They Are Efficient At Removing.

Regardless of the CADR figures, it’s important that you choose a purifier which has the best technological processes for the type of pollutant that you are concerned with. As we have already explained, the CADR figures don’t tell you anything about removal of particles below 0.1 microns or about removal of gases, odors and micro-organisms. You may be more concerned about allergens such as pet dander or pollen.

Check out my Types of Air Purifier and The Type of Pollutants They Remove article for the full story.

What Level Of Filtration Efficiency Do You Require?

If you are allergic to particles of a very small size, then what the filtration efficiency is for a certain size of particle may be an important factor. As we have seen AHAM in their CADR figures is not concerned with particles less than 0.1 microns. However, you may need a higher level of filtration efficiency for particles of less than 0.1 microns. As an example, viruses are all less than 0.1 microns in size. Some parts of tobacco smoke are less than 0.1 microns.

For the full details about the levels of filtration efficiency check out my article on How Effective Are Air Purifiers? Check out our home page for specific air purifier reviews of various models.

I hope that these articles help you in choosing the best air purifier for your needs.