Air Purifier or Ionizer – What’s the Difference?

If you’re considering purchasing an air purifier, one of the first decisions you’ll need to make is whether to choose a HEPA air purifier or an ionizer. Both types are marketed as being effective at clearing allergens, impurities, and other troublesome particles from your home’s air, but how are they different? Is one type more effective than the other?

The air that we breathe plays a major role in our health, so buying the best air purifier for your home is an important choice. This is especially true if you suffer from allergies, asthma, or if you struggle with a respiratory condition. Therefore it is critical that you fully understand the functional differences between models and how much maintenance each type will require before deciding.

In this article, we break down the most important differences between HEPA air purifiers and ionizers so you can make an informed choice as to which air purifier is best for you and your home.

How HEPA Air Purifiers Work

High-Efficiency Particulate Air (HEPA) filters are widely regarded to offer the highest standard of air purification on the current market. To qualify for the ‘True HEPA’ label, these air purifiers must undergo rigorous testing and meet certain criteria before they are approved.

HEPA filters must be capable of capturing at least 99.97% airborne particles which are 0.3 microns or larger. ‘Microns’ are a method of measuring the tiniest of airborne pollutants, allergens, and other particles that are often microscopic and undetectable to the human eye. One micron is equivalent to one-millionth of a meter. Many HEPA filters are able to trap even smaller particles, but 0.3 microns and above is the benchmark they must reach to be granted the HEPA name. When you consider the human eye is incapable of distinguishing anything smaller than 10 microns, this really puts into perspective just how small these particles can be.

HEPA filters use a tightly-packed web of woven fibers to trap airborne particles that are drawn into the filter. The manner in which they are captured depends upon the size and shape of the particle and how it collides with the filter. Large particles are easily trapped on the surface of the filter’s web, while medium-sized particles may manage to get through the first layer before becoming snagged in the inner layers. The smallest particles often escape the first few layers, but even these eventually become caught on a fiber within the filter before they’re able to make their way through to the other side and back out into the atmosphere. It is these small particles that the filter must be able to trap to be awarded the HEPA name.

Some HEPA air purifiers are relatively simple in design, using only a fan and a HEPA filter to clean the air. But other models may combine a HEPA filter with additional technology, such as ionizers and antimicrobial filters, to further improve their efficiency. Ionizers charge incoming airborne particles with a negative electrostatic charge, which makes them more easily attracted to the fibers within the filter. Additional antimicrobial layers ensure that bacteria, allergens, and viruses cannot grow on the filter to help extend filter life and overall air quality.

How Ionizer Air Purifiers Work

Ionizer air purifiers are distinct from HEPA air purifiers because they don’t use a web of fibers to trap pollutants and often don’t have a filter that needs to be changed regularly to ensure effectiveness over time. Ionizers use an electrostatic charge to remove airborne pollutants, allergens, and other unwanted particles from the atmosphere in your home. They release negatively charged ions into the air, which attract positively charged ions, such as dust and allergens, and then bind together with them.

Because the ions have bonded together, this makes the troublesome particles much heavier than they were before. As a result, these over-weighted particles are no longer light enough to stay airborne and drop to the ground. Once they have landed on the floor, they are much less likely to be inhaled and can be easily vacuumed up.

Some ionizers come complete with a special electrostatic collection plate which attracts these heavy particles and traps them on its surface. This plate must be washed regularly, but it can be reused over and over again without losing its effectiveness.

Is There Any Difference In Overall Effectiveness?

As we have seen, the biggest difference between HEPA air purifiers and ionizers is the manner in which they remove particles from the atmosphere. Is one option, though, more efficient than the other? To answer this question, we need to consider the range for each type as well as the potential for airborne contaminants to become recirculated once they have been initially captured.

HEPA air purifiers pull air into the unit and circulate it through a high-quality, tightly-woven filter to capture pollutants. Once the air has circulated through the filter and been cleaned, the purified air is blown back out into the room. The troublesome particles and pollutants which have been trapped in the filter remain there until the filter needs to be changed. As long as you change the filter when recommended, there’s no risk of them leaking back out into the atmosphere. Thus, HEPA air purifiers are an extremely effective method of keeping the air in your home free from contaminants.

As described earlier, ionizer air purifiers don’t use filters to trap unwanted airborne impurities. Instead, they use electrically charged ions to weigh down particles and make them fall to the floor or become attracted to a charged collection plate. Either the particles are cleaned from the floor and surrounding surfaces by the homeowner, or the collection plate is wiped clean and replaced. Therefore, when it comes to an ionizers overall effectiveness, the onus is really on the homeowner. Since the particles are not securely trapped within a filter, they can become disturbed and stirred back up into the air if the home isn’t cleaned regularly. While ionizers which use charged collection plates limit this possibility, they are still not as effective as HEPA filters in trapping particles and preventing their return to the air.

Another issue with ionizing air purifiers is that the charged ions they produce are not suitable for everyone. There has been research which suggests that these charged particles can actually irritate asthma symptoms, thus negating any beneficial effects of better home air quality.

When choosing between a HEPA air purifier or an ionizer, you should also consider the effective range of each device. Depending on their size, HEPA air purifiers usually offer the greatest effective range if you have a large area to cover. While some high-end ionizers are capable of covering 2,000 sq ft or more, most models are limited to ranges less than 600 sq ft.

HEPA vs Ionizer – Cost Considerations

HEPA air purifiers are generally more expensive than ionizers. This is due to the quality of the filters used and the strict requirements they must meet to be granted the HEPA certification. You must also consider the additional cost of new filters, as HEPA air purifiers will fail to work effectively if the filters are not changed regularly.

Ionizing air purifiers use simpler technology and are thus a cheaper option than HEPA air purifiers. They also require less maintenance, as they don’t require the use of filters which must be changed to maintain their effectiveness. If an ionizer uses a charged collection plate, this can be washed and reused for the lifetime of the appliance. Overall, ionizers make a much more affordable choice if you’re on a budget or hate the hassle of remembering to change filters.

HEPA Air Purifiers vs Ionizers – Design Choices

While the style and design of your air purifier obviously shouldn’t be your primary concern, being able to choose a model that fits with your home decor is certainly a plus.

In general terms, HEPA air purifiers are available in a much wider selection of sizes, shapes and designs than ionizers. Many models are also wall-mountable and come in a range of colors which increase the chances of finding the right design to blend seamlessly with your home.

On the other hand, ionizers offer a much more limited selection of styles. Most models are large, tall, and cylindrical and must be placed on the floor. Some types of ionizers are more compact and can be placed on a shelf, desk, or table, but these smaller options have a lesser effective range than their larger brethren.

Overall, unless you have a very modern home with lots of futuristic gadgets around, ionizers are less likely to blend in with your decor than HEPA air purifiers.

Final Thoughts

Both HEPA air purifiers and ionizers have their benefits when it comes to removing troublesome pollutants and other unwanted particles from the air in your home.

HEPA air purifiers must meet strict standards before they can be granted the HEPA label and are therefore a highly-effective choice for improving air quality for you and your family. Particles sized 0.3 microns and above are securely trapped within their dense filters, remaining there until the filter is removed and disposed of. They are available in a wide range of sizes and designs, but are expensive to buy and maintain over time.

Ionizers are a much more economical option. These air purifiers do not require costly filter changes and are more affordable at the point of purchase. On the downside, ionizers can be less effective than HEPA air purifiers at completely removing allergens and other particles from the atmosphere.

With ionizers, particles are not securely trapped within a filter but instead litter your home surfaces waiting to be cleaned up. Therefore, should you fail to keep on top of your chores, these particles can be stirred back up into the air again. Furthermore, ionizers are available in a limited range of styles and designs, which may make it difficult for you to pick a model that complements your home decor.

Further Reading