Spring is finally here. Now it is finally time to throw the windows open and get some fresh air. Unfortunately, with sunshine and flowers come red eyes and runny noses. This is not only due to allergies, but also pollutants such as dust and smoke. The EPA estimates that concentrations of certain pollutants are up to five times higher indoors than outdoors.

Want to enjoy your home without inhaling so many pollutants? Air purifiers are here to help. Maybe you’re actively searching for relief from poor indoor air quality or maybe you’re just curious about how much of a difference an air purifier could make. Either way, here is what to consider when you’re weighing your options.

The Technology

Nowadays there are tons of different options when it comes to air purifiers, and the biggest difference between models is the technology used to actually purify the air. For the most part this comes down to the filters. The most common and reliable way many different models work is through the use of a mechanical filter. These force air through a web of fibers that trap particulates. The gold standard is the HEPA filter, or "High Efficiency Particulate Air" filter. In order to qualify as a HEPA filter, it must remove at least 99.97% of bacteria, mold, dust, pollen, and any other airborne particles with a size of 0.3 microns. This is an important consideration, as lower quality filters will advertise with claims of HEPA-like, or HEPA-type.

Another technology worth considering is the activated carbon filter. As the name suggests, these filters use activated carbon to capture certain odor-causing molecules and gases in the air. Many air purifiers will use a combination of technologies, so ones with both a HEPA filter and activated carbon filter can be great for tackling the widest range of airborne pollutants.

Beyond the two filter types are a diverse set of technologies such as electronic charge, UV lamps, and Photocatalytic Oxidation (Popularized with the Molekule air purifier). While there can certainly be some benefit, the current scientific research is still new, and there are already reports of subpar performance and even harmful byproducts produced from some of these models.

The Size

Potentially the most important factor when considering which air purifier to buy is the size of the room you’re going to use it for. There are certain units made for the entire house, but those are usually niche models that require special installation. Normal units are made to be operated in a single room in the house, and the power of the unit will reflect that. When selecting a particular model you want to determine the approximate square footage of the room it will go in.

Additionally, the CADR (Clean Air Delivery Rate) reflects the volume of clean air in cubic feet per minute that the unit will produce on its highest setting. Now of course we don’t expect you to pull out your ninth-grade geometry textbook and a set of blueprints to figure out which air purifier you need, but you should keep in mind that a small air purifier won’t cut it for a 500 square foot living room, and a large purifier might be overkill for a bedroom less than 200 square feet.

The Price

You’re obviously considering price with every purchase you make, but there are some specific considerations when it comes to deciding which air purifier is best for you. First and foremost, the price of the actual unit varies wildly, and it is largely based on the size of the room the unit can clean up effectively. To this end, you can’t cut corners if you’re trying to clean up a larger room. Getting a smaller unit to save a few bucks will unfortunately mean that the unit will be ineffective.

The next thing to consider is the fact that your air purifier will be running 100% of the time. This means that the noise will be a factor, and that your energy bill will increase with an added machine constantly running.

Finally, you will have to routinely clean or replace the filters. On one hand, a dirty filter means the machine is doing its job and all of that gunk is trapped in the filter instead of down your lungs, but on the other hand you have to factor in the cost of potentially buying new filters to replace the old ones.

Final Thoughts

The options are seemingly endless when it comes to air purifiers, but the right unit can really improve your air quality inside the home. That being said, you really pay for quality when it comes to making a worthwhile choice. This is a machine that will be running all the time and potentially be responsible for cleaning the air for a very large room. You’re going to want it to work for a long time, and you’re going to want it to work well.

The best reviewed air purifier on our list, plain and simple. Whether it is the best performing, the most attractive, or the highest rated, this model wins it all. It has not only made an appearance on almost every list we consulted, but also received outstanding marks wherever tested.

This model is recommended for larger rooms up to 540 square feet and uses a 3-step filter including a pre-filter for larger particles, HEPASilent filter, and carbon fiber filter. Their mechanical filter component is technically not a True HEPA filter, which may raise alarm bells, but its performance in hands-on testing was more than enough to put our fears to rest.

Additionally, this unit has the AHAM Verifide seal so you know their CADR and room size guidelines are legitimately tested as well as an Energy Star rating, meaning it has met the strict guidelines of the EPA program and is more energy-efficient than the unqualified models in its class.

Next up on our list is the Coway AP-1512HH. This unit is designed for mid-sized rooms up to 361 square feet. Unlike most of the other units in consideration, this model received a lot of special attention for its portability. Most models are specifically designed to be placed in a single room and run continuously, but the Coway was repeatedly singled out for being easy to move room to room, or even travel with.

Additionally, the unit received high marks from multiple reviewers for its quiet operation. It even includes an automatic speed, which detects the quality of the surrounding air and adjusts speed accordingly. The filters are relatively cheap and the unit is Energy Star certified. All of this together means that the unit is on the cheaper side to own and operate.

Ease of use aside, this model performed quite well when it comes to the actual function of purifying the air. It uses a four-step filtration, including a pre-filter, True HEPA filter, carbon filter, and optional vital ion. This last ionic filtration step is not an enormous benefit, and potentially may produce ozone during operation, which might be harmful, but this is easy to turn off altogether if you so choose.

Frequently cited as the best value air purifier when compared to the competition, the Honeywell Home HPA300 is recommended for larger rooms up to 465 square feet for an incredibly competitive price.

This model is larger and clunkier than some of the others made for the same workload but received near-universal high marks for its performance. Despite its bulky appearance, the model also reviewed very well for its quiet operation.

The Honeywell boasts a True HEPA filter along with an Energy Star certification, and is generally cited as being cheap to operate. However, it is worth noting that the company makes a point to say you should only use Honeywell replacement pre-filters and filters, and these should be replaced every six to twelve months.

We have covered models for mid-to-large size rooms, but our top pick for smaller rooms, and cheapest on the list by far, is the Levoit Core H132. We want to again stress the importance of paying for a quality product that will work as intended, but if the room you need to keep pollutant-free is a bedroom, kitchen, or a small apartment living room, maybe you don’t need a big, expensive model.

This is where the Levoit Core H132 comes in. Recommended for spaces around 86 square feet, many reviewers were impressed with this unit’s performance in these smaller spaces, especially bedrooms. It also comes with a sleep mode to lower the fan levels and can be used as a night light if you so choose.

The model comes with a 3-stage filtration system including a pre-filter, True HEPA filter, and carbon filter. It does a solid job for the price, with cheap replacement filters to boot, and gets a lot of mentions for how well it handles pet odor.

We don’t have state-of-the-art labs for testing or a fancy algorithm that can crunch mountains of data. Instead, we simply turn to the people that do! Our method is to look at every method, and we do this by researching the researchers and reviewing the reviewers. Did an expert rate something highly for its ease of use, but the user reviews say it was difficult? Did something get a low score on one site, but is at the top of the list on three more? The amount of options to choose from can be overwhelming, but the amount of reviews has become overwhelming too. We compare and contrast the data from the major reviewers and come up with our own take on what is right for you.