Pros: This basic air purifier stands out for its quiet operation and ability to clean rooms up to 500 sq. ft. We love that it has four fan speeds and additional sleep and turbo modes for a variety of air cleaning needs.

Cons: The design is not as streamlined as other models we tested, and the filters are more costly than those of similar air purifiers.

Summary: A well-built air purifier, but its filters will end up costing you in the long run. For budget-minded users, the GermGuardian is a better value.

Pros: The attractive Alen BreatheSmart is a top model built for serious air cleaning. It stands out for its SmartSensor technology that adjusts airflow automatically to best remove impurities. Lifetime warranty.

Cons: Works very well, but it is expensive for what you get, and it also requires costly replacement filters.

Summary: An attractive, but overpriced air purifier that effectively uses carbon filtration technology to clean the air in small to very large spaces. Its high price puts it out of reach for some users.

Pros: Its state of the art technology is used in hospitals to kill the widest range of airborne germs. Has a variety of settings to fit almost every need.

Cons: High upfront cost, but its efficient operation will end up saving you money in the long run.

Summary: A well-made, quiet machine with technology that is hospital- and FDA-approved. Expensive, but worth the price for those who need advanced air cleaning technology.

Pros: An affordable air purifier by a trusted name in the industry. This model effectively reduces pollutants in rooms up to 390 sq. ft., using HEPA filters that are easy to install and inexpensive to replace.

Cons: A few units have been known to rattle, but this isn't a consistent problem with the entire product line.

Summary: Our recommendation for basic air purifying needs. A no-frills air purifier that is affordable and low-cost to maintain.