17 Best Air Purifiers (Review) In 2021

When you are considering an air purifier it's important to make sure it contains a filtration system that can do the job of clarifying particles in the air. Most modern purifiers use activated carbon with HEPA air filters that work together to clean indoor air. We have listed a number of facts and features in our product review for a range of air delivery clarifiers, but finding the best air purifier to suit your needs first means that you need to research certain types and have an understanding of how certain air ratings are achieved.

ACH stands for 'Air Changes per Hour and a purifying device will normally be labeled as, say, 3x or 5x. This basically tells us how many times the air is circulated around a space within an hour. In brief terms this is an important rating - the lower the number, the worse it is at cleaning the air than one rated higher so 6x filters six times an hour, and is better than 5x which cleans five times an hour, etc. The better the rating, the better it is at freshening the air. There is some additional mathematics you can use which can tell you how much extra space in cubic feet, or square feet, can be achieved but we'll leave this to the experts. You could search for it using CFM (cubic feet per minute) which is shown on all models under their specification, then use your favorite search engine to find out more about maximizing your purifying product usage.

CADR stands for 'Clean Air Delivery Rate' and this outlines how well the product can clean air throughout a specific space. It's a certified measurement that provides manufacturers with a standard rating to supply consumers with, and a good measure that gives you help when comparing purifiers. Although there are certain mathematical techniques used to reach the CADR rating, in basic terms the higher the CADR  number gives you an evaluation of how effective the product is at cleaning the air. So a CADR of 400 would be more efficient and clean the air better than air purifiers with a CADR of 300. The CADR 400 is speedier at cleaning airborne particles than one advertised at CADR 300.

Ozone is something that is produced in order to break down and react with any type of thing that it comes into contact with. This has advantages and disadvantages, in fact, the same thing that makes it great can also make it a danger in certain circumstances. Ozone can be effective at breaking down airborne pollutants and dust pollen as well as mold spores and mildew, so a purifier that produces ozone can be beneficial. A HEPA filter and a TrueHEPA filter is usually designed with in-built ozone filtration to remove odor. When these filters are combined with pre-filter (for collecting dust pollen and particles) and an activated carbon filter, a device can trap around 0 3 microns at 99.97% effectiveness.

If ozone is being produced enough to eliminate smells, it can also trigger reactions in your eyes, nose, skin, and lungs. It is highly recommended that when purchasing an air purifier that it isn't for residential use as the emissions can be harmful. In fact, they are powerful and should only be used in controlled environments - and may be dangerous to small animals as it's a volatile chemical. Ozone producing air purifiers can deliver clean air in, say, environments that have recently flooded, because residents and pets would be removed from such concern before professionals get to work.

Even an energy-efficient purifier will consume on average around the same energy as a modern refrigerator but of course, this is dependent on the model and energy input it requires to run effectively, and the energy output it produces. It is recommended that they are used where you sleep, work, and spend time around your space for around 10-12 hours to keep the air around you clean - this means, for example, one that is rated 5x over twelve hours will run the air around the filtration system 60 times. Some people will set the device on high for a short time before using a room, then turn the intake down to reduce noise. It is not recommended to run any residential air purifier when there is nobody home so always switch it off when you are out. This is for safety as well as ensuring you are not wasting energy.

If you are looking to reduce the spread of viruses and searching for a purifier that will help clear airborne particles and bacteria you will need to make sure you buy the right one for your space. Most of the best air purifier models will filter air in just minutes, dealing with particles like mold, those from pet hair, dust, allergens, and more. Depending on which space you intend to use a purifier in, the room size is important; buying a device that covers 220 square feet and putting it into a room double that size will mean that it isn't as effective as it should be. When reviewing air purifiers, take a look at the room size and the square feet that it advertises, and don't forget to do your own sums so you know the calculations before you start. You will only find the best air purifier for your room/s if you don't 'guess' the area size. If you are buying just one device and will move it around the home, get an air purifier for the largest room which has adjustable fan speeds so you can turn down the intake for smaller spaces.

The room which you use the most should ideally provide the best results. If you suffer most from asthma or allergies during the night then the bedroom is the best place. Get the placement within the room too. For example, in the bedroom, air purifiers should ideally be placed up to eight feet from the headboard so you feel the full benefits but not the draft from the device. If you are placing air purifiers in a selection of rooms, make sure that you don't put them behind furniture as they need to pick up on the air quality of the whole room. Generally, the intake is at the front of the machine, some at the top, so to get the best from your machine avoid under shelving units either.

The majority of modern air purifiers are designed to be as quiet as possible while still using a powerful motor. Look at the manufacturers' specification if the noise is going to be an issue for you, your family, and your pets. The quietest air purifiers will run up to 25 decibels (dB) and the loudest can be up to 70 to 75 dB. When operating an air purifier you will find that those with different filters will run at different noise levels. Those with HEPA filters will make noise when the motor is switched on. Some air purifiers have a night mode or can be adjusted to run at a lesser fan speed and therefore built to be quieter on these settings. You can run the device on high before you enter a room for a short while to clean the air quality rapidly, then turn down the intake or switch to night mode while you use the room. An air purifier built with an air ionizer runs quietly in the majority of cases while still clearing indoor air but may not work as effectively as those with HEPA filters.

Let's begin by stating that upgrading air quality is a benefit that you can't see. Unlike, say, an air conditioner where you will feel the cool air and its obvious benefits, clean air is invisible so to reduce the risk of overspending or purchasing the wrong purifier, research the type of filtration system that best fits your needs. Let's start with the well-known term 'HEPA filters':

A High-Efficiency Particulate Air filter is superior to any washable types. It is replaceable and depending on how you use the device and its capacity the new HEPA should be changed every six months up to a year or two. Don't be fooled by this 'buzz word' though, whilst this type of filter works well, it will not do the job of 'medical grade' filters. If you need a medical-grade system, expect to pay plenty more for a professionally certified medical grade purifier.

A HEPA-based device is not the same as one that uses a true HEPA filtration system. True HEPA filters will remove particles as small as .3 microns, look out for that familiar figure a manufacturer or retailer uses - "certified to remove 99.97% of particles."

Adjustable fan speed is a must whether it is changed on the device switches directly, via a smart app, or a remote. This is both for noise control and electricity usage. Turn the fan speed on low or set it on high for a short while before you enter a room if you want it to run yet not be over-noisy. Highest speeds will ensure that the device is working at full capacity, clearing the space using it's ACH rating.

It's essential to know who is selling you the product if there is a warranty available and if it needs to be registered (and who with), what it covers, and of course how long it lasts. Some will offer an optional extended warranty in addition to its standard guarantee (sometimes free upon optional registration, sometimes a small fee is required). Some retailers will offer a 30-day general money-back warranty, with manufacturers promising a full year or more. The filter in an air purifier is a consumable item. Even if a filter can be washed it will still need to be replaced eventually, and a HEPA filter, in general, cannot be washed at all. Warranties are minefields so check all the small print first as you may find it only covers certain faults or is restricted to workmanship defects.

For the best air purification, the size and capacity of the device depend heavily on the room size. Simply measure the square feet of the room or adjoining rooms. For instance, if you are intending to use it in the lounge at 300 square feet, and the office at 200 square feet, you will need to find a purifier with a CADR rating of 500sq ft.

Remember that it isn't the size of the device itself, but its ability to provide clean air in the space you intend to use it. Also, remember that air is a volume and not an area so the square footage takes into consideration the height of the room too.

Smart air purifiers will give just as good air quality as expected but they have extra features that help make its usage more rewarding. Look for things like:

• Filter maintenance sensor
• Air quality monitoring
• Remote and/or voice control
• Real-time history monitor

Don't spend more on a smart purifier if you aren't taken by the features, go for a lower-priced non-smart model.