5 things to consider when buying an air purifier

Pollution levels are constantly hitting new highs every year, making living in cities extremely dangerous. Air pollution in cities like Delhi is almost an annual topic of news, with newer statistics telling us that the city has become a greenhouse of sorts for contaminants. At such times, those suffering from allergies and diseases like asthma find these devices incredibly useful in keeping their problems under check. But the issue with buying them is of course the fact that they are still in their nascent stages in the Indian market. This makes selecting the right model for you a task. A salesman might help you out with it, but it always helps to have useful knowledge beforehand. Hence, we’ll be listing out in detail the five most important things to consider while buying a new air purifier.

Room size

This one’s a pretty straightforward factor. An air purifier always has an optimal room size listed in its specifications, which allows it to perform all its functions easily. For that of course, you must first calculate the area in square feet of the room in which you will be using it. You can then read the specs list and find the ‘coverage area’ section of any air purifier model to decide whether it’s apt for your room. So if you have a room that’s sized at 400 sq. ft., you can buy an air purifier rated for that much or slightly higher coverage area. Appropriate models are available for all room sizes. While buying an air purifier, also keep in mind where you will be placing it in your rooms. These are not tiny devices by any means, and will occupy a corner or wall space. So always look for models that are portable if you’re going to be moving them a lot.

Types of filters

The most common type of filter used in air purifiers, and also the type you must’ve heard about a lot, is HEPA, which is an abbreviation for High Efficiency Particulate Air. Models rated for HEPA can filter around 99.97 percent air borne particles of small sizes of up to 0.3 microns. These include particles like pollen, animal dander, mold spores and of course, dust. People suffering from allergies must always ensure that a HEPA filter is present onboard their air purifier. As for those who wish to get rid of foul odours, they can opt for an activated carbon filter (ACF). Light mesh based ACFs generally remove cooking odours, while those containing activated carbon pellets can get rid of gaseous and chemical odours. For staying away from bacteria and germs, look for models with an antibacterial coating. And if you want to increase the life of your air purifier, opt for a model that comes with a washable pre-filter for collecting dust and other large particles.

CADR rating

CADR stands for Clean Air Delivery Rate. It basically tells you how efficiently and quickly an air purifier works. It measures how many cubic feet of air can be filtered in one minute for different categories such as pollen, dust and smoke. That means the right CADR value for your air purifier also depends on the room size. For a room up to 200 sq. ft., the value must be at least 134 CMH, and for a 450 sq. ft. room, it should be at least 300 CMH. A room of up to 680 sq. ft. will warrant a CADR value of at least 453 CMH. As for larger rooms, the value must go upwards of 500 CMH. Air Changes Per Hour or ACH is another factor worth knowing about. It denotes how many times an air purifier can clean the air of its claimed coverage area in an hour. The ideal ACH is 4, so do consider this value before you buy an air purifier for yourself.

Noise and energy rating

Image credit: Dyson

It’s natural for an air purifier to produce noise, but if you’re someone who doesn’t want a noisy environment, check for their noise levels. You can get this info online through user reviews or also on the official pages of the models you are considering. 35 decibels is the ideal noise level when the fan is running at top speed. If this value is above 55 decibels, the air purifier will tend to be disturbing. Many air purifiers also come with a sleep mode that reduces noise levels to the bare minimum, so that’s another factor to consider. Energy star ratings are also offered to air purifiers, so look out for them before you buy one. Better rated models consume electricity efficiently, not resulting in big spikes in your monthly bills.


Image credit: Honeywell

Proper maintenance from time to time is necessary for an air purifier to have a long life. One of the most important aspects of this maintenance is filter replacement. These filters trap dust and other particles, which means they get clogged up over time. HEPA or carbon filters need routine replacements. You can find their ideal replacement intervals on their official pages, or will be notified about the same by the machine itself, when it’s time. Their costs can run up to high values sometimes, so do keep that in mind before purchasing an air purifier. Cleaning the washable pre-filter regularly can also enhance the life span of the other filters.