The following questions will help you in determining what you need to consider when purchasing an air purifier in the United States.

What are you trying to filter out of the air?

How big of a room/how much airflow do you need to be filtered?

What is the air purifier constructed out of?

What is the running cost of the system?

How often will the system be running? 24hr operation?

How noisy will the system be while it’s running?

Most air purifiers are used to remove dust and allergens, but to what degree they do it is where the difference lies. Some air purifier manufacturers use clever wordplay to lead people to believe their filters are certified and HEPA rated. US government HEPA rating is 99.95% efficient at 0.3 microns, if the filter is not at least this efficient then it simply is not HEPA.

The size of the space needing filtration will play a significant role in your decision. One thing to understand is that a given surface area of filter media can only handle so much airflow before the rated efficiency starts to decline. Big filters with large surface areas will be able to provide high airflow without sacrificing efficiency. This means that those units can provide the filtration rate that larger rooms require. Smaller units have small filters that can still be as efficient but they just won’t be able to provide the same airflow.

If chemicals and odors are needed to be filtered out, then a different filter type is required. Activated carbon will capture these gas molecules, depending on a few variables. In order for activated carbon to be effective, it needs a minimum amount of time for the air to pass through to capture the gas.

What is the air purifier constructed out of? If it’s plastic and large rubber components then it might be outgassing chemicals that sensitive lungs can very easily react to. Metals such as steel and aluminum do not produce odors and make for an incredibly rugged system that will last a lifetime.

Running cost and filter replacement can easily be overlooked when purchasing an air purifier system. How much energy a system uses will depend on the motor size, motor efficiency, and the filter surface area. The filter surface area will limit how much air can be moved through it while still maintaining its efficiency. This is where companies will fall short so check what airflow the efficiency was tested at.

Noise level of a unit depends on motor isolation and insulation. If the construction is plastic vs metal, then the metal will dampen the vibrations and frequencies in that range more than plastic will.