An allergy air purifier can significantly reduce the levels of allergens you are exposed to and thus help you to control your allergy symptoms throughout the year.
A good allergy air purifier is designed to reduce dust, house dust mite, pollen, mould spore and pet dander allergens. This article will discuss all the information you will need when purchasing an allergy air purifier.
A huge range of natural allergens can trigger allergy symptoms. What size these allergens are, and understanding when you will be most exposed to them, will help you to define what allergy air purifier you need. Both the filtration efficiency and filtration technology used in the allergy air purifier, and the time of year to use it, will be key. Most people that suffer with allergies will have one or two primary allergens that trigger their symptoms and one or more secondary allergens. To effectively control your allergy symptoms both primary and secondary triggers should be well controlled.
Any good allergy air purifier will need to be able to effectively take dust mite allergens out of the air in your home. Dust mites are tiny creatures that tend to live in your bedding, mattresses, carpets, and furniture. Dust mite allergens are not the dust mites themselves but the protein in their droppings and decaying bodies. These allergens are about 0.1 to 40 microns in size and can cause mild to very severe allergic reactions. Exposure to dust mite allergens is common throughout the year, making an allergy air purifier useful all year round. Exposure levels, however, might be highest during winter when the indoor climate is predominantly humid, warm and dark.
Pollen grains are between 3 and 100 microns in size with most grains being between 20 and 35 microns. Pollen grains can, however, break apart into smaller pieces that can be around one micron in size – requiring an allergy air purifier with a high filtration efficiency. Flowers, grass, weed and trees release pollen grains, and the pollen season typically runs from May to September.
Dust consists of particle pollution made up of human skin, traffic soot, soil, dirt, dead insect parts, mould and other organic material. Settling dust ranges in size from 1 to 90 microns, however, ultrafine particle dust is significantly smaller (down to 0.001 microns) and can stay airborne indefinitely. An effective allergy air purifier will achieve several complete air exchanges per hour in a given room. Allergy to dust is not seasonal, as dust can be found throughout the year in most homes.
Pet dander is skin flakes shed by animals that are around 0.1 - 10 microns in size. Exposure to proteins such as an animal's urine, sweat and saliva on airborne skin flakes can cause severe allergy and asthma symptoms. Pet allergens have a particularly long ‘shelf-life’ and can stick to clothes, hair and skin, and thus are able to travel long distances. An effective allergy air purifier for pet allergies should use leakage free HEPA filtration but can also be equipped with high quality activated carbon filters to take unwanted pet odours out of the air. As you might share your home with your pet, exposure to pet allergens will be continuous throughout the year. Due to less open doors and windows, the winter months might expose you to higher levels of pet dander and thus increase your allergy symptoms.
Mould spores grow on decaying matter, inside and outside the house. The mould itself is not an allergen but the spores it releases cause an allergic reaction for most people suffering with allergies. Mould multiplies by producing microscopic spores, which are 3 – 200 microns in size. These mould spores then get airborne and will grow further mould in places where the conditions are right, i.e. places that are wet and dark. There are many different kinds of mould and it can be found anywhere in the house. Mould spore allergy symptoms can occur throughout the year as the spores are released when there is a sudden rise in temperature in a moist environment. A good allergy air purifier will capture mould spores before they can settle and grow more mould colonies, so a high airflow rate for the allergy air purifier is recommended.
In order to achieve the best performance from your allergy air purifier, you should have a clear idea where the unit will be used. The room size is an important factor when selecting an allergy air purifier. The higher the filtration efficiency of the allergy air purifier the fewer air exchanges will be required to clean and maintain good air quality in your room.
Achieving two complete air exchanges (while being conveniently quiet enough) per hour should be an absolute minimum. If the allergy air purifier has a less than ideal filtration efficiency (i.e. less then 99.95% at 0.3 microns) or is not leakage free, then more air changes will be required to achieve a significant reduction in allergens in the air. Most allergy air purifiers we tested will need to produce about 4 – 6 air exchanges per hour, with 2 air exchanges being only acceptable for the most efficient HEPA air purifiers.
The filtration efficiency in some allergy air purifiers drops significantly after months of use. This will result in a reduction of the amount of clean air released into the environment.
There are four different types of air purification technologies that are commonly offered in allergy air purifiers. Those are HEPA filtration, ionisation, combustion and electrostatic filtration. Here are some of the pros and cons of each technology:
HEPA filtration is a very popular technology in allergy air purifiers for its ability to capture the smallest size of particulate pollution (including all above mentioned common allergens) as well as their completely consistent filtration efficiency. A drawback of HEPA filtration is that a HEPA filter will require a very high-quality filter and overall air purifier construction to be effective. A low-quality allergy air purifier with a HEPA filter will most likely be ineffective, as the air purifier will either not move enough air or have large amounts of leakage (i.e. a very low filtration efficiency).
Ionisers can make good allergy air purifiers but should only be used in combination with a proper mechanical filter. Ionisation works by creating a static charge around the airborne contaminants floating around within the room. Once the particles have been charged they simply stick to the nearest surface. Ionisers can be useful allergy air purifiers, as the technology is relatively cheap but yet effective. Be aware, however, that the filtration efficiency in an ioniser allergy air purifier will decrease significantly over time until the filter is replaced. The range of Blueair air purifiers are the most sophisticated and popular air purifiers that use ionisation.
An electrostatic filter in an allergy air purifier works by either being electrically charged when new or by producing a small amount of friction when the air passes through the filter, creating a small natural electrostatic charge between the polypropylene and the layers of bonded polyester fibres in the allergy air purifier. The electrostatic charge is then supposed to attract household dust and other particles to the electrostatic filter when they pass through it. An electrostatic filter can be effective in capturing a broad range of large allergens and is offered in a range of different allergy air purifiers such as the range of allergy air purifiers from 3M. A drawback of an allergy air purifier with an electrostatic filter is that the filtration efficiency is not consistent and the original electric charge often wears off quickly.
This type of technology incinerates pollution, including natural allergens. This can effectively render natural allergens non-allergenic. However, the combustion technology requires that these allergy air purifiers have a very low level of airflow (i.e. if the air moves through the unit too quickly, then the allergens will not be exposed to enough heat to be destroyed). The only company that offers combustion in air purifiers is Airfree. Airfree says that the low level of airflow their air cleaners produce is not a problem, because the air that comes out of the unit is “so clean”. We do not agree, as the minimum of at least 2 air exchanges per hour already assumes that the air is completely clean.
The sound is something you should consider particularly if you are planning to use your allergy air purifier in the bedroom. The noise level of an allergy air purifier will vary depending on the speed setting it is used on. Be sure to check that the airflow that is being produced is achieved on a speed setting that is appropriate in regard to the sound pressure. We often see allergy air purifiers advertised with great airflow only to find that the sound pressure at that speed setting makes the allergy air purifier unsuitable for most environments.
The maintenance of an allergy air purifier will require can vary drastically. Some allergy air purifiers such as the Bioniare BAP9240 and the HoMedic AR-10A-GB require the filters to be cleaned and vacuumed every month. Blueair air cleaners require that their filters are changed every 6 months and IQAir air cleaners require a filter change every 12-48 months.
The running cost of your allergy air purifier will predominantly depend on the type of unit you have along with the filters used in it. The Blueair air purifiers require the filters to be changed every 6 months although this will vary on the level of pollution and usage. The IQAir air purifiers have more than one filter so the frequency of change is not the same for all. As the IQAir HealthPro 250 uses three filters, the pre-filter and carbon filter need to be changed on average every 12-18 months, and the HyperHEPA filter every 3-4 years. However, again this will vary on the level of pollution and frequency of use. There are units that will require filter changes every 1-3 months which can be significantly costly.
The two best allergy air purifiers that we would recommend are the Blueair 205 and the IQAir HealthPro 100:
The Blueair 205 is a small, compact and effective allergy air purifier. It is ideal for small rooms and effective in removing allergens such as dust mite, mould spores, pollen and pet dander. It uses ionisation in combination with a mesh filter, and the filter will need to be changed every 6 months.
IQAir HealthPro 100
The IQAir HealthPro 100 is a very powerful and sophisticated allergy air purifier. This unit effectively removes all particulate pollution including common allergens such as dust mite, mould spores, pollen and pet dander, but also traffic and industry pollution and bacteria and viruses. It offers 470m3 of clean air per hour, making it suitable even for large rooms.