Energy & Certifications
Best Air Purifiers
Which Is the Best Air Purifier?
We tested 10 air purifiers to find the quietest, most energy-efficient model and compared their Clean Air Delivery Rates (CADR) with industry standards. We found that the Coway AP-1512HH is the best overall air purifier. It's one of the lightest we tested, weighing around 15 pounds, so you can move it from room to room as needed. Its timer and auto modes clean the air in your home only when needed. Finally, it's one of the most energy-efficient air purifiers we tested.
The Whirlpool Whispure AP51030K has the best CADR scores out of all the models we tested, making it highly capable of removing indoor pollutants. It's also the quietest air cleaner we tested, so you can sleep with it in your room without much issue.
The Idylis AC-2118 has an auto mode that switches settings based on air quality, a sleep mode that cleans the air without disturbing you, and a timer you can use to schedule cleaning on specific times and dates. It also has relatively high CADR scores, meaning it can effectively remove airborne pollutants.
Why Get an Air Purifier?
In certain studies, Environmental Protection Agency researchers have found indoor air pollution can be much worse than outdoor air pollution. This is because indoor air usually doesn't circulate beyond the walls of your home, which lets particulates and pollutants build up. These pollutants can cause a variety of health problems.
In preparing for this review, we spoke with Janice Nolen, assistant vice president of national policy for the American Lung Association. She said that those who most benefit from cleaner air are "people with asthma or allergies, especially children and teenagers, and older adults or people with cardiovascular problems."
However, Nolen also told Top Ten Reviews that "removing the source of the pollution problem or adding ventilation [is] far more effective than plugging in a device." After taking steps to remove pollution sources and ensure good ventilation, Nolen suggests using an air purifier as a supplement to filter out airborne particles that can intensify asthma, allergy symptoms and cardiovascular conditions.
Decoding Air Purifiers
The CADR score was created by the Association of Home Appliance Manufacturers (AHAM) to show how much filtered air a purifier delivers. Each CADR score has three parts: smoke, dust and pollen. Higher CADR scores mean the machine is better at removing airborne pollutants. Not all air purifiers have CADR scores, so we suggest choosing a model that lists them.
Adjusted Area Coverage
CADR scores also help you determine the size of room to use the machine in. AHAM takes the smoke CADR score and multiples it by 1.55 to establish an air purifier's recommended room size. It's not a good idea to use an air purifier in a room larger than its rated size, as it becomes less effective or useless. Instead, you want an air purifier that can handle a larger room than you plan to use it in.
Air Changes per Hour
In general terms, this is an indicator of how much air the purifier can clean in an hour. While a filter can't produce completely clean air each time, a higher airflow increases the chances for grains of dust or pollen to stick to the filter later on. For example, if your room is 250 square feet and you purchase a purifier rated for 500 square feet, you effectively have a purifier that will make two air changes every hour.
Every air purifier we tested uses industry-standard HEPA filters, which remove 99.97 percent of 0.3-micrometer particles. Many air purifiers also use carbon pre-filters and secondary filters to capture larger particles so you don't have to replace the HEPA filter as often, which can reduce strong odors. Some air purifiers include other filters to help remove particulates such as pet dander and germs.
Ionizers charge particles as they pass through the machine so they attach themselves to a surface, thus removing themselves from the air. Ionizers are somewhat common in air purifiers but controversial, as they produce trace amounts of ozone.
"Ozone is an outdoor air pollutant," Nolen told Top Ten Reviews, "and it's a very dangerous pollutant that causes asthma attacks and has been linked now to cardiovascular disease and certainly causes premature death."
Because of the risks associated with ozone, the American Lung Association does not recommend using ionizers in your home. We suggest choosing an air cleaner without an ionizer or with one that you can turn off. We did not factor whether an air purifier has an ionizer in our scoring.
Some air purifiers use ultraviolet (UV) light as a cleaning method, but its effectiveness is debatable. Although UV light is a common way to sterilize medical equipment, contaminants need exposure to UV over a long period for it to make a significant difference. The longer you use a purifier with a UV cleaning stage in the same room, the more effective it will be. However, air moves through purifiers quickly so particulates don't get much exposure, reducing its effectiveness. We don't consider UV cleaning stages a critical feature in an air purifier.
Air Purifiers: What We Tested, What We Found
During our air purifier tests, we assessed noise levels and energy use to develop a deeper understanding of each model and help you find the right one for you. We don't have the facilities to test the purification, but we think the CADR scores provided by AHAM are an accurate way to judge air cleaner effectiveness.
We tested the noise each air purifier makes on both its lowest and highest settings. We found that noise levels were around 30 dB on average, about the volume of a whisper, on their lowest settings. At their highest settings, many purifiers can reach 60 dB or greater, which is almost as loud as a vacuum cleaner.
As you search for an air cleaner, make sure you consider which room you plan to put it in. Noisier air purifiers may be too disruptive for you to get restful sleep. However, if you use the machine in the kitchen during the day, noise levels don’t matter as much.
Our other test measured how much energy each machine uses on its maximum settings, which can help you determine how much a purifier will affect your energy bill. Generally speaking, these machines are inexpensive to use daily, as the most expensive purifier from an energy standpoint runs at around $60 a year, or $5 a month.
What Else to Look for in an Air Purifier?
Additionally, many air purifiers have a sleep or quiet mode that sets the machine at its lowest fan setting so it can run without disturbing your sleep. Some models dim the lights or have an auto-adjust feature to change the purifier's settings after a few hours, usually eight, in this mode.
Look for an air purifier with an auto mode, which uses an air-quality sensor to detect pollutants in the air and adjust the cleaning settings to meet what is needed. This feature increases the effectiveness and efficiency of the purifier, only running on higher settings when needed.
If you want to use the purifier in multiple rooms, moving it around as you need, make sure it is light enough to move or carry with ease. A timer can also be useful since it runs the purifier for a few hours before turning it off automatically. Some models let you schedule when the machine turns on, which is convenient when you leave for the day or on vacation.
Look for a warranty that lasts longer than a year for peace of mind that you won't need to buy a new air purifier if you find an issue.
Energy & Certifications
On average, we found air purifiers use around 86 watts of energy on the highest setting, and choosing a purifier that uses less energy than this average could cut long-term energy costs. You can also save energy by looking for Energy Star certified products, as they are usually 20 to 30 percent more efficient than federal rules require.
There are also certifications that show products meet certain safety standards such as the approval of the California Air Resources Board (CARB). Of the 10 air cleaners we tested, eight have both Energy Star and CARB certifications as of the publishing of our review.
Contributing Reviewer: Sean Peek