At under $100, this budget-friendly, top-rated air purifier from Levoit is our top overall pick and will meet most consumers' needs for use in a small- to medium-size bedroom, office or living room. This purifier has a three-stage filtration system consisting of a pre-filter, a HEPA filter and a high-efficiency activated carbon filter to capture allergens, pet hair, dander, smoke, mold, odor and large dust particles as well as airborne contaminants as small as .3 microns. The controls are easy to use, and with three fan speeds to choose from, the lowest setting is quiet enough to use in a bedroom overnight. This model does come with a nightlight option, but you can also completely turn off the control lights, too. The manufacturer recommends cleaning the pre-filter every two to four weeks to maintain its effectiveness, replacing the HEPA and carbon filters every six to eight months.

Our Editor Says: "I love that the lowest setting is quiet enough to use while sleeping, and there's an option to turn off all of the control lights if you're sensitive to lights at night. Plus, this thing is great for reducing odors — you could barely tell when I cook salmon for dinner with this machine running."

Another solid, budget-friendly buy is Blueair's Blue Pure 411 air purifier. It features a three-stage filtration system, starting with an interchangeable, washable pre-filter that catches larger particles like dust and pet hair. It comes with two pre-filters, one blue and one gray, but you can buy more colors separately to best match your home's decor. After the pre-filter, the air passes through both a particle and activated carbon filter which catches virtually every airborne particle: pollen, dust, pet dander, mold spores, smoke, allergens and bacteria. It features one simple control button that allows you to switch from low, medium, high and off and is whisper quiet on its lowest setting. And while the upfront cost is on the lower end compared to most top purifiers, this Energy Star-rated pick will also save you money over time thanks to its low energy usage and affordable replacement filters, which cost and should be replaced every six months with consistent use. While it doesn't feature fancy bells and whistles or smart technology (though a $20 upgrade to the Blueair Blue Pure 411 Auto model gets you a purifier that can adjust its mode based on the particles it sense), this purifier gets the job done and would be perfect for small to medium bedrooms and offices.

Our Editor Says: "This purifier works wonders on odors. I accidentally spilled tea tree oil in my bedroom and the scent overwhelmed the whole room. I turned this baby on its medium setting and let it run overnight, and in the morning, the odor was barely noticeable. I love how low-profile and sleek this purifier is, too — I can tuck it in a corner and barely notice it."

For purifying a larger space, we like this upgrade pick from LEVOIT. This option also has a three-stage filtration process, including a preliminary filter, a HEPA filter and then an activated carbon filter. The three filters work together to remove and absorb 99.7 percent of airborne pollutants and particles such as dust, lint, hair, pet dander, VOCs, ammonia, formaldehyde, benzene, hydrogen sulfide, mold spores, pollen, smoke, odors and fumes. On max power, it can clean up to 900 square feet in one hour or 500 square feet in 33 minutes, and there are three fan settings, as well as a smart auto mode that can adjust between three fan speed settings in response to real-time air quality readings. There's also an option to set a timer for it to shut off between one and 12 hours. It's also rated by Energy Star as one of the most energy-efficient air purifier options. With three fan settings, this purifier is also quiet enough to use in a bedroom without interrupting sleep. On average, the filter should be replaced every six to eight months. For $10 more, you can purchase a smart version of this model with Wi-Fi for app and voice control. On the downside, since this air purifier is on the larger size, it's a little trickier to find discreet locations for it.

Our Editor Says: "I noticed that my house smelled less musty. I like that the auto-mode feature does the hard work for you by detecting air quality and adjusting the fan speed to match what your space needs. I also like the air quality color indicators that make it easy to keep tabs on the air quality in your home."

For small spaces like bathrooms, laundry rooms, litter-box rooms or hotel rooms, a plug-in air purifier you can easily move is a great option. The UV-C light helps kill airborne viruses such as influenza, staph, rhinovirus and reduces 99.97 percent of airborne particles and allergens including dust mites, pet dander, pollen, smoke, mold and bacteria. Since there's no filter, you don't need to worry about replacing filters frequently, but the UV-C bulb does need to be replaced every 4,000 to 5,000 hours or 10 to 12 months, depending on use. As a con, it’s not as quiet as our tester anticipated. There’s a noticeable hum that you can hear when you enter the room, but it becomes white noise after you get used to it. She thinks you could definitely sleep with it on, and the soft hum may actually help you sleep if you're a fan of noise machines.

Our Editor Says: "I put this in an outlet near my cats’ litter boxes, and I’ve definitely noticed a difference (aka the smell doesn’t knock you out when you enter the room). An out-of-town guest even said she couldn’t tell I have cats — that’s a BIG win."