An air purifier is a device which removes contaminants from the air in a room. These machines are considered beneficial to those suffering from allergies, asthma and other respiratory problems. Commercially-graded air purifiers are manufactured as stand-alone units as well as larger units that can be part of a building’s HVAC (heating, cooling and air conditioning) unit. Air purifiers can be found in homes and offices, as well as in medical, commercial and manufacturing industries.
Air purifiers work in one of two ways: by collecting air and passing through a filter; or by discharging substances to neutralise dirt in the air (such as ions).
How to choose an air purifier
Choosing the right air purifier for your business can be daunting.
The size of the room is an important consideration. In order to properly clean the air in a room, the purifier will need to exchange the air in the room several times per hour. Two air exchanges per hour is considered a minimum, while five is optimal. If the room is large but the air purifier is small, it will have to operate on the highest setting, which means that it will be very noisy. Buying an air purifier rated for a larger room will allow you to run it effectively on lower speeds, resulting in quieter operation.
The filtration efficiency of the air purifier is also important. There is a great deal of variation in the market. Numerical efficiency is calculated as the percentage of particulates trapped in a filter during a single air exchange. The higher this number is, the better. The best purifiers trap particulates in one pass at well over 90%.
The air flow relates to how much air is passing through the filter. Look for a combination of high filtration efficiency and high airflow, also called the “clean air delivery rate” (CADR). This is indicated in cubic feet per minute of 100% particle-free air created by the air purifier.
Filter change indicator lights are helpful when it comes to the optimal time to change a filter. Forgetting to change the filter will mean that the machine is not working properly, which is sub-optimal for health.
The ease with which filters can be changed is also important. Ideally, your air purifier should not require any tools to replace filters: a door should pop out, allowing the filter to be removed and replaced.
The filters of some air purifiers are tedious and difficult to change, which causes people to delay changing them.
The weight and mobility of the device is also important. Many come on castors, so that the purifier can be pushed from room to room. Small, lightweight purifiers are ideal for moving between different offices and buildings.
When purchasing an air purifier, consider ozone emissions. Ozone is a toxic substance and is undesirable, especially for those in poor health. Ensure your air purifier is ozone-free.
The cost of maintenance is another factor to consider. The expression “penny wise, pound foolish” is apt here as more expensive air purifiers are often the least expensive to maintain, saving you money over time. The warranty and reliability of the machine is key – most have a five-year warranty for the main fan and motor parts. A reliable air purifier should have no problems with the motor, fan, and electrical components and controls during that time. The rest of the air purifier consists of the filters, which need periodically cleaning or replacement.
Common air purifier myths
You don’t need to dust
Air purifiers do not lift the dust off the surfaces of windows, walls or furniture; they merely filter particles already in the air. The area will still need to be cleaned as usual.
Air purifiers fix allergies
This is not true: an air purifier is only part of allergy control. Allergens like pollen fall to the floor or settle on surfaces, and the air purifier can’t filter them once they are no longer air-borne. The same holds true of dust mites.
Regular cleaning of the environment should still take place, and anti-allergy cleaning agents should be used in conjunction with other appliances like dehumidifiers and steam cleaners.
Air purifiers remove odours
Many people think that having an air purifier is a substitute for cleaning as it removes odours. Air purifiers only eliminate odours if they filter the air through high-grade carbon. Good hygiene is a better solution to everyday odours from cigarettes, rubbish or dirt.
The only way is HEPA
Many people think that air purifiers with an HEPA (high efficiency particulate air) filter are automatically better than other varieties. Because HEPA filters vary in size and construction quality, this is not necessarily true.
You can keep your windows closed
Air purifiers do not necessarily exchange fresh air. Open your windows for at least an hour every day for new air to enter and circulate. Let the air purifier take over after that.
Speed doesn’t matter
Consumers often run their air purifier at low speeds in order not to hear fan noise. Unfortunately, this reduces the square footage an air purifier will effectively cover. If your air purifier can’t run at high speed without making a noise, it is best to choose a time to run it at full speed and then turn it to low when necessary.
Air purifiers remove cigarette smoke
Air purifiers actually remove the particles left behind when people have been smoking. Most air purifiers — except for a few which have been specifically designed remove both the odour and toxic gases associated with smoke — are not capable of doing this.
Air purifiers remove viruses and germs
Some air purifiers boast the addition of ultra violet to kill viruses. In most air purifiers, the amount of time that allergens have in front of ultra violet light is not sufficient to kill them. Only a few air purifiers have an enhanced HEPA filter sufficient to capture viruses, or a technology such as a steriliser which uses heat to kill pathogens.