Seven Things to Consider When Buying an Air Purifier
With air quality in Silicon Valley and beyond pushing to never-before seen levels, many are turning to air purifiers to help filter smoke and other particulate matter from inside their homes. If you are in the market for one of these air-cleansing devices, here are the top seven things to consider.
1. Size & Portability
The location and square footage of the space where the air purifier will be used plays a large part in which one you should purchase. These devices come in sizes ranging from those that can sit on a desktop to hefty, stationary units. The smaller ones are easily moved room to room as needed while the largest units are best left in place. Others have casters, allowing them to be wheeled around.
The larger the space, the larger the unit needed to properly purify the air. Small, lightweight units are great for small home offices or nurseries while the bigger devices are ideal for spacious living, family, and great rooms. If you are unsure of the size needed for your space, it is better to choose one that is bigger than needed; something too small will not be effective.
2. Pollutants
The device you purchase should filter out pollutants specific to your health and lifestyle requirements. Some are more effective on airborne allergens while others remove smoke, pet dander and dust, and even others can remove odors. If you are looking for a filter that improves overall air quality in your home, purchase a device that performs well across the board.
3. CADR Ratings
CADR, or Clean Air Delivery Rate, is a numerical value that indicates the volume of particulate matter that a purifying unit will remove from the air. Measured in cubic feet per minute (cfm), the higher the number, the faster the device will clean the air in a room.
The CADR scale was created by the Association of Home Appliance Manufacturers (AHAM) goes up to 400-450, which also gives an indication of the unit size needed based on square footage. It also takes into account three types of common particles: smoke, dust, and pollen. Smoke is 0.09 to 1 micron while pollen is considerably larger at 5-11 microns.
The AHAM suggests multiplying the CADR by 1.55 to determine the size of the room the unit in which should be used. This calculation is based on an 8-foot ceiling height. For example, a device with a CADR of 100 will work well in a 155 square foot space. AHAM also recommends using the smoke CADR rating for this calculation as it filters the smallest particulate matter.
4. Filter Type
There are two types of filters, the pre-filter, which traps large particles and can be washed, vacuumed, or replaced, and the main filter, which is the most important when deciding upon an air purifier.
Endorsed by the Environmental Protection Agency (EPA) and American Lung Association, HEPA filters are the gold standard when it comes to air purifying devices. These filters removed 99.97% of airborne particles 0.3 microns or larger. When choosing a device, be sure it is a genuine HEPA filter and not a knock-off or HEPA-type filter.
Activated carbon or charcoal filters will remove odors, smoke, trap gases, and VOCs. These filters must be changed regularly to provide maximum efficiency.
CADR ratings are determined in optimum, controlled test environments and not all devices undergo this voluntary testing. The actual CADR rating can be impacted by drafts, humidity, and other elements, reducing the unit’s efficiency.
Some units also boast UV or ionic processes, but the effectiveness hasn’t been proven. Ozone, a lung irritant, can result as a byproduct from units employing these filtration methods.
5. Noise
Decibel levels for air purifiers varies from 17 dB, a low “rustling leaf” sound, to upwards of 60dB, which emits a sound like an air conditioning unit 100 feet away. If noise is a concern, check the product specifications and opt for a device lower on the decibel scale.
6. Ongoing Costs
An air purifier is not a purchase it and forget it appliance. They require ongoing maintenance to operate at optimum efficiency. The cost of replacing filters is a primary and necessary cost outlay. Some filters last years while others must be replaced more frequently.
Another cost to consider is energy use. For these devices to properly clean the air in your home, they must be running continuously. Wattage runs from 1.5 for small units to 200 for large, power-hungry purifiers. Some units are Energy Star-certified, meaning they are more efficient, while others have an “eco-mode,” placing the device in stand-by mode when it detects no airborne particles.
Estimate the average maintenance and energy use cost per year to assist in choosing a unit that meets your budget.
7. Bonus Features
Like most appliances, you can purchase additional add-ons like smart functions, a remote control, automatic timers, and more. If budget is of no concern, then some or all of these features may be worth having. But if you wish to get the best purifier possible while staying within a certain budget, forego these extra features. They are “nice to have” but not necessary.
There is no perfect air purifier to meet all needs. The top things to consider when choosing the right device for your home and your needs is the CADR rating, filter type, pollutants, and unit size. Next on the list should be noise and ongoing costs, with extra features taking up the rear.
The EPA has a guide to residential air purifiers and Consumer Reports is another great source for a list of the best air purifiers on the market. Here is their Best Of 2020 list.
