Got allergies, odor, or other air quality problems in your dorm? Picking a great air purifier’s a smart decision.
In this post, I’ll show you 5 of the best air purifiers for college dorms along with the details & pros and cons to know before buying.
There’s also some helpful basic information to help you learn more about air purifiers and what they do. Read on to find out more and see some of the best buys for your money!
- 1 How do air purifiers work?
- 2 What is a HEPA filter?
- 3 What is a pre-filter/activated carbon filter?
- 4 Room size and choosing the right purifier for your needs
- 5 Understanding the Clean Air Delivery Rate (CADR) rating
- 6 What kind of air purifier do I need?
- 7 ★ 5 of the best air purifiers for college dorms ★
- 8 Additional reading
How do air purifiers work?
Most popular air purifiers sold today like this GermGuardian AC4825 use a highly effective design with one or more filters. These are efficient at cleaning the air as, unlike other products sold using gimmicks, they remove contaminants from the air you breathe. They do so by circulating the air in a room and cleaning it as it passes through the filters.
While there are different kinds sold out there, most air purifiers work using a simple, but effective, concept: They use fans to move air through a very dense type of filter material called a High-Efficiency Particulate Air (HEPA) filter to permanently trap unwanted particulates.
They’re both efficient and safe as they don’t produce any by-products that can cause headaches or other symptoms that products like ozone generators can cause. In addition, most of the better quality purifiers sold also include 1 or more added filters or cleaning stages to do things like trap hair or dust and odors, too.
To trap odors and airborne chemical vapors, also called volatile organic compounds (VOCs), a filter with activated carbon is used because of its odor-absorbing properties.
A filter stage called the pre-filter may or may not be separate from the odor-absorbing filter and has another purpose. It catches larger particulates like pet hair, dust, and fibers before they can reach the main (HEPA) filter and can even be vacuumed for longer life.
It’s all about cycling and cleaning the air
As they run they circulate the air in a room, continuously cleaning it. Purifiers are recommended for rooms like dorm rooms based on the square foot size which affects how much air must be circulated.
For example, a small room purifier has less air to circulate and clean and can use a smaller fan. While a large or medium-room purifier has to use faster or multiple fans to circulate & clean the air efficiently.
Purifiers are often (but not always) rated on how many times they can circulate & clean the air for their greatest recommend room size.
Most also have selectable fan speeds and you can set them to a low speed for quiet operation at night. You can also find some with bonus features like a germ killer to eliminate airborne microbes.
What is a HEPA filter?
A “true HEPA” is a filter meeting the Environmental Protection Agency (EPA) standard set back in the 1950s. This standard requires that the filter can trap 99.97% of all substances entering it.
A HEPA filter can remove contaminants smaller than a microscopic 1/1,000,000 of a meter (1 micron) in size! That’s way below what the human eye can see.
As an example, dust and hair are very large while dust mite particles are close to 5 microns in size. Pollen is close to this size as well. However, some air quality problems like smoke can be much smaller, including below 1 micron wide.
An up-close look at a HEPA filter with a foam seal around the edges. Used in air purifiers and other air cleaning systems, they’re made up of very dense fibers in a folded shape held in place inside a frame.
HEPA filters are made of a very dense, folder material made up of fibers that allow air to pass but stop airborne contaminants. Electric fans draw in air, force it through a filter, and the clean air is released back into the room.
As I mentioned earlier, HEPA filters meet a standard in which they can trap 99.97% of all particles that pass through them. This means that for every 10,000 particles than enter a HEPA filter, only about 3 escape!
They’re used for a range of air problems such as:
- Allergens (plants, pets, etc)
- Pet dander & hair
- Dust mites
- Dust & fibers
- Smoke particles
What is a pre-filter/activated carbon filter?
The most effective air purifiers include both the HEPA filter section and a pre-filter/activated carbon section, too. They work together to remove not just microscopic particles (as the HEPA filter is best at) but also odors, vapors, and larger elements like pet hair or dust.
As I mentioned earlier, air purifiers may include an extra filter called the pre-filter. This is a section which, when added along with the main HEPA filter, gives some extra benefits. They’re often a mesh-like material and in many cases can be replaced separately as needed.
As a HEPA filter can last a range of months (8-12 months for example, depending on circumstances) it’s great if we can extend its life before replacement is needed.
A pre-filter can trap things like larger fibers, hair, and dust before they can reach and prematurely clog up the main filter.
An example of dust buildup on one of my air purifier’s pre-filters. Since there’s so much buildup of dust, it’s smart to vacuum it off to keep the filter working and airflow good until replacement time.
In many cases, once the pre-filter has become very dirty (like dust buildup) you can brush it off or vacuum it to keep it working well until replacement time comes.
Most quality brands include an activated carbon treatment on the pre-filter itself. Activated carbon can absorb and trap odors and volatile organic compounds (VOCs) that are bad for your health or can cause headaches, coughing, and other problems.
In many, but not all, purifiers, you can replace these separately to keep maintenance costs low. That’s great, since why should you replace the HEPA filter and spend money when it’s not needed yet?
Room size and choosing the right purifier for your needs
A purifier is usually recommended by the manufacturer based on the (largest) room size to use it in. While in a few cases it may be listed in cubic feet, normally this room size is given in square feet. To figure out a room’s size in square feet, just multiply the width times the length. In the example above, this AC4825 model is good for rooms up to 155 sq. ft. in size. That’s a room of about 10 x 15 1/2 feet in size.
What you’ll find when shopping is that many have a recommend maximum room size they’ll work for. It’s not that they can’t work in larger rooms. However, an air purifier that’s good for smaller rooms like college dorms can’t move enough air efficiently in larger rooms.
Most of the time, an air purifier is recommended for a room size (small, medium, large, etc) based on square feet. To find out the square feet size of a room, just multiply the length times the width.
Understanding the Clean Air Delivery Rate (CADR) rating
Example of a CADR label provided by some, but not all, air cleaning appliance manufacturers. The 3 numbers shown tell you the effectiveness of the purifier’s air cleaning.
In case you’ve never heard of it, the Clean Air Delivery Rate (CADR) is an industry-standard way of testing and determining an air cleaner product’s effectiveness.
The Association of Home Appliance Manufacturers (AHAM) is an organization that verifies home appliances for the industry. While they’re nice to have for comparing similar products, CADR rating tests are voluntary and not required by law.
CADR ratings are numbers used to help you know an air cleaner’s performance before buying. The rating numbers are based on “higher is better.”
In order to find out how well an air purifier cleans the air, 3 types of tests (smoke, pollen, and dust) are performed in a controlled lab environment and the performance is given a rating. The purifier is then given a rating the manufacturer may display in ads or specifications if they like.
What to know when shopping
There’s one problem, though. For lower-priced air purifiers, even from high-quality brands, it’s not unusual for them to not include CADR performance numbers.
When it comes to small room air purifiers, you can definitely assume that there aren’t any CADR numbers provided then it’s somewhere under 100.
In fact, somewhere around 75 is probably a good guess. That doesn’t mean they’re not good quality, but it’s just harder for a very small purifier to move as much room air as a bigger model can.
Therefore, it’s easy to see why better-performing models are those recommended or medium or large-sized rooms – they have more fans or a more powerful fan design.
What kind of air purifier do I need?
Examples of products that claim to use special features like ozone or ions (charged air elements) to clean the air. Left: An ionizer air purifier. Right: An ozone generator. Ionizers aren’t as effective as a filter-based purifier and aren’t recommend. Ozone generators are similar, but can be more effective but only at dangerous ozone production levels. Both can produce by-products that can irritate your breathing passageways and are best avoided.
Stay away from “ionizers” and ozone generators! These are often very ineffective and a waste of your hard-earned money! The level of ozone at which point they become effective at purifying the air is unsafe and will cause several health problems (or at the very least, discomfort).
★ 5 of the best air purifiers for college dorms ★
Our top picks at a glance
|GermGuardian AC4825||Check at Amazon|
|Levoit LV-H132||Check at Amazon|
|GermGuardian AC4100||Check at Amazon|
|Hamilton Beach TrueAir||Check at Amazon|
|Holmes HAP9240||Check at Amazon|
Product reviews and details
1. GermGuardian AC4825 – A best-selling model that’s also a good value, too.
Hands-down, the GermGuardian AC4825 is one of the all-time best-selling air purifiers today and it’s easy to see why!
You’ll get not only more room coverage for your money but the addition of an ultraviolet (UV) germ killing feature, too.
Take a look at why it’s one of the best well-rounded values today:
- True HEPA filter
- UV-C germ killing feature
- Super-easy filter maintenance
- Inexpensive replacement filters
- Separate pre-filter for reduced costs
- Filter check reminder feature
- Carrying handle for easy moving
- Available in white or the AC4900 style, too
- Lab tested CADR rating of 100+
- 155 sq. ft. room coverage
Good air purification performance
The true HEPA filter and odor-absorbing pre-filter work together to keep your dorm room fresh, reduce allergies, and let you breathe & enjoy college the way you deserve.
Nasties such as dust, hair, and more get blocked by the pre-filter which can be replaced separately to keep costs down. The HEPA filter works great to block all kinds of terrible allergens, dust mites, pollen, and even mold spores to freshen the air you breathe and reduce sickness.
Unlike many competitors in its price range, the AC4825 also offers lab-tested performance with a CADR of 100+.
While it may lack the fancier features found in others, it’s one of the easiest to use and very reliable as well. I’m a big fan as I own one myself!
In fact, you can read more in my detailed review of the AC4825 here.
Top-down view of the control panel. A simple 3-speed fan rotary control is easy to use for anyone. The power indicator LED will blink to remind you when it’s time to check the filters.
A 3-speed fan control is provided and a great choice for those who prefer simple controls & operation.
The filter is easy to remove and replace by opening the rear door and simply swapping it out. A replacement reminder is included as well.
UV-C germ killing feature
When switched on, the UV-C feature also doubles as a nice glowing blue trim around the front and sides. It’s a cool look I love as I own one myself!
The ultraviolet light feature (UV-C) works with titanium oxide to break down & destroy illness-causing microbes & germs in the air around you. It’s a nice addition that most competitors don’t offer.
When switched on, you’ll see a soft, safe glow in the translucent trim around the base of the top that lets you know it’s working to destroy germs.
At 22 inches in height, it’s not as compact as other models, but fits well into corners or other spaces. Replacement filters cost about $15-20 and last about 6 months depending upon use. You’ll also find many 3rd part options offered for those of you on a budget, too!
The GermGuardian line of purifiers is one of the most reputable on the market, and without a doubt the AC4825 is a true “workhorse” that people love, judging by the thousands of great buyer reviews.
I’ve enjoyed mine, too, and I love how hassle-free it is to use. The fan speeds are good, it’s relatively quiet, and works well to solve a whole range of air quality issues.
The true HEPA filter and pre-filter are some of the easiest to replace I’ve ever used! If you’re in the market for a good value but not a wimpy purifier, it’s a great compromise between cost & performance.
While it’s not as quiet as some competitors, it’s still pretty low in noise when running. But that’s one of the few tiny gripes I have since I’ve enjoyed mine so much.
- Simple 3-speed fan switch is great for nearly everyone
- Better overall value for the dollar vs competitors
- Great filtering performance
- Quiet fan operation on low speed setting
- Germ & microbe-killing UV-C feature not found in many others
- Filter replacement reminder
- Nice blue glow when UV-C is on
- Soft LED when power is on
- Tower shape is great for corners or areas with vertical space
- Good room size coverage (155 square feet)
- 3-year limited warranty
- No auto-sensing modes
- No electronic controls
- No auto-off feature
- Cannot wash & reuse filter (can vacuum)
- Older design vs competitors like Levoit
- Warranty requires paying for return shipment for service
As a happy owner, I can say it’s a solid, reliable purifier that works well to clean the air and is definitely a good choice for the money. I love mine so much I bought other GermGuardian models to use and test, too!
It’s a great match for your dorm room or bedroom while you’re at college.
Take a moment and see why it's one of the all-time best selling purifiers today at Amazon.
Good news! You can now get the AC4825 we happy owners love in white as well.
Want some a bit different looking? Check out its twin, the sleek AC4900CA version here.
2. Levoit LV-H132 – A great addition to your college dorm. Quiet air cleaning + nice features.
GermGuardian isn’t the only air purifier company to pay attention to – Levoit has produced some true winners like the LV-H132 for a few years now.
Without a doubt, it’s one of the quietest purifiers I’ve ever tested & owned!
Because of its stylish looks & compact design, it’s a great match for dorms, bedrooms, study halls, and much more. The LV-H132 uses a 3-stage true HEPA filter that’s great at eliminating odors, allergens, pet dander, dust mite by-products, and a lot more.
The LV-H132 provides electronic touch controls. It’s simple to use and works well. Additionally, a memory feature means that upon the next power up it returns to the last settings you used.
Of the products listed here, it offers the most features in addition to a very pleasant and quiet operation on low speed.
A built-in night light with 2 brightness settings is a bonus feature.
The convenient filter replacement reminder lets you know when it’s time to inspect the filter and replace it if needed.
Replacement filters run around $30 and are simple to replace by opening the top cover.
Overall, I’m impressed. After much testing and use, I really enjoyed using it.
- Shorter height than competing tower purifiers
- 2-year warranty
- 3 fan speeds
- Night light with 2 brightness levels
- Nice looking, modern design
- Electronic soft button controls
- Quiet operation on low level won’t disturb sleep
- Filter replacement reminder
- Great build quality & high reliability
- Easy filter replacement
- Smaller room coverage than others in its price range (129 sq. ft.)
- No auto-off timer feature
- No air quality sensor
- Electronic controls may not be suitable for some
It’s an excellent purifier with wonderful buyer reviews and great air cleaning performance.
UPDATE: A sleek new black version is now available too!
3. GermGuardian AC4100 3-in-1: Super-compact air cleaning for offices, dorm rooms, and for a lower price.
A great budget-priced model (around $50 or so), the AC4100 has an excellent reputation and is a nice little purifier that’s great for smaller rooms.
Measuring only 7.5 x 6.5 x 11″ in size, like other best-selling GermGuardian models it uses a true HEPA filter & activated carbon section to produce fresh, clean air and permanently remove those terrible air contaminants and odors that make your college dorm uncomfortable.
Check out what you’ll get for how little you pay:
- True HEPA filter
- UV-C germ killing feature
- Super-easy filter maintenance
- Inexpensive replacement filters
- Separate pre-filter for reduced costs
- Filter check reminder wheel
- Also available in kids version (AC4150) in 3 colors w/ night light
Ultraviolet (UV-C) germ killing feature
You wouldn’t expect it for the price, but you’ll also get a germ killing feature activated by a switch on the front. A UV light along with titanium dioxide work to destroy germs and microbes for healthier air and reduced sickness.
Filters and replacement
Filter maintenance on the AC4100 is super-easy! Just pull the tab and remove the rear cover. Next, you can easily remove the filter assembly. You’ll be done in seconds.
Replacement filters cost about $10+. For your convenience, there’s a filter installation date wheel on the rear to help you know when it’s time to replace it.
Using it is very easy with the 3 speed fan control. It’s quiet and generates a pleasing low noise level on the lowest setting. When set to high a sound like white noise is produced.
Unlike other models, the UV-C is an on/off switch and not a pushbutton control.
Like some other GermGuardian models I’ve tested, I’m not thrilled that there are no indicator lights for the UV-C feature being turned on or filter replacement. You’ll have to check the switch to see if you left it turned on as there’s no light.
Also, because of the compact size, it’s not the absolute quietest you’ll find, either. Still, it’s fairly quiet compared to others I’ve owned, and shouldn’t be a problem for sleeping or studying.
However, those are fairly minor complaints and overall it’s a well-made little purifier that’s a good choice. In fact, I reviewed the AC4100 in more detail here.
- Simple 3-speed fan control and on/off UV-C switch
- UV & titanium dioxide design to kill germs
- Great filtering ability for its small size
- High speed setting moves a lot of air for purifying quickly
- Filter replacement reminder wheel (month installed)
- Low filter replacement price (about $10+)
- Filter replacement date wheel (marks month installed)
- Sleek, modern design
- 1 year warranty is shorter than other models
- Fan speed on high could be slightly better
- No filter replacement reminder
- No more colors offered
- No indicator light for UV-C “on”
Following the same great quality that has made GermGuardian purifiers some of the best today, it’s a great choice.
Definitely worth reading the many great buyer reviews that helped a best seller at Amazon.
4. Hamilton Beach TrueAir Ultra Quiet – Compact, affordable, and quiet!
have a tighter budget? The Hamilton Beach TrueAir Ultra Quiet isn’t just affordable but also a well-made and compact popular model.
The genuine HEPA filter can be vacuumed clean. With the exception of heavy use, you won’t have to replace it as often as other products. You’ll not only save money for the upfront cost but in maintenance, too!
Controls are simple and easy to find on top. There’s an easy-access release for opening the filter for maintenance, too.
What I really like is how simple it is to use via the 3-speed rotary control. It’s a pretty quiet purifier, too, and you can sleep peacefully without worrying about being disturbed at night.
It’s small at only 8.5 x 13.5″ but the room coverage is a great 140 square feet. It’s a good choice for small rooms & offices.
One of the best things about the True Air is that it can be turned on its side to fit into smaller areas. Nice!
Nice! With the True Air, you can easily vacuum off the HEPA filter for extended life. It’s a great feature I love.
One drawback is that there’s no activated carbon/pre-filter section like some more expensive competitors or the GermGuardian AC4100. However, the easy access for cleaning the HEPA filter helps make up for that.
It’s available in both a nice black color and white as well. One weak point is the lack of odor absorption, so if bad smells are an issue in your room it’s not a good choice.
Otherwise, if you’re in the market for a small room purifier that’s affordable (below $50) and great for dorms, it’s a great option.
- HEPA filter effective for average dust and allergens
- Main (HEPA) filter can be vacuumed and reused
- Can be used on its side
- Quiet operation
- Nice design
- 2 color options
- Simple 3-speed operation control
- Limited room size coverage
- No pre-filter or carbon filter section
- No power indicator lights or filter replacement reminder
- No sleep or auto-shutoff mode
Need small-room relief for dust, allergens, and more? It’s a nice affordable option worth checking out, especially with thousands of great buyer reviews!
Take a moment to see why it's one of the best-selling small purifiers at Amazon.
5. Holmes HAP9240 HEPA-type desktop purifier – A low-cost performer & great for dorms!
Looking for a competent but lower-priced choice? The Holmes HAP9240 may be exactly what you’ve been looking for. You’ll get a great compromise between performance, filter options, and price.
It’s not the smallest but measures a reasonable 14.8 x 11.4 x 7.2 inches in size.
Featuring a small size that’s perfect for countertops, shelves, and even desks, the Holmes can also be placed vertically on its back. The purifier features built-in rests on the rear to allow it to stand on its end.
For around $50 or so, it’s a good value. Check out the features:
- Near-HEPA air filter quality for less money (filters 99% of particles)
- Up to 100 sq. ft. room size coverage
- 3 cleaning speeds and low noise operation
- Filter reminder indicator light
- Optional ionizer feature
- Can be used in a vertical position
- Black color option (availability may vary)
- 3-year limited warranty
- Washable pre-filter
- Affordable replacement filters
- 12 month HEPA filter life
The Holmes desktop air purifier includes a washable filter and HEPA-type filter (left). (Right) Have special air cleaning needs? You’ve got some good options! Pick one of the 3 additional filter options for specialized air cleaning relief.
It uses a HEPA-type filter that’s similar to the filtering qualities of a true HEPA filter. The filter can remove 99% of all particles down to 2 microns in size (as opposed to the 0.3 micron standard of a genuine HEPA filter.)
It’s a budget model but still a good performer for many common air quality problems. The 2-micron particle size rating works well for pet dander, dust, and standard allergens.
I wouldn’t recommend it for cigarette smoke, however, at least not without a carbon filter.
Shown: The Holmes HAP9240 controls are super-simple to understand and use. The filter reminder (left) shows the filter condition and can be reset as needed. Right: The optional ionizer feature is as simple as an on/off switch with light. Center: Choose from Off or 3 fan speeds with low-noise operation.
A built-in ionizer with off/on control is an extra feature that produces a safe level of charged molecules that bond with pollutants in the air. While it’s not the main air cleaning contributor, it’s a nice touch you may enjoy.
Filter check reminder
At power up, the unit will check and show you if it’s time to check and clean or replace the filters using the dual-color light on the control panel. When needed, you can easily reset the check filter light using the reset button provided.
It’s unique in that the pre-stage filter can be removed and washed to be reused. Fan speed is adjustable and while not as quiet as the Levoit and others here, it does offer low noise when at low speed.
Room size coverage and air cleaning performance
It’s recommended for rooms up to 100 square feet in size – just right for dorm rooms! The air cleaning performance is good, too, as it removes allergens, dust, pet dander, and much more from the air very well.
While there are quieter models out there, you’ll pay at least $30-$40, and in my opinion, it’s very quiet on the lower 2 settings. Overall, it’s a nice little budget model I’m sure that’s a great match if you’re on a budget.
Just like experience with it, buyers love it, too, as it’s one of the best-reviewed budget purifiers today.
- One of the most affordable and biggest sellers on the market
- 100 sq. ft. room coverage
- Easy slide control switches & 3 speed settings
- Pre-stage filter can be cleaned and reused
- Low replacement filter cost
- Additional filter options
- Can be positioned vertically
- Includes ionizer with on/off control
- Lower cost version of a true HEPA filter with nearly the same standard of performance
- Available in black
- 3-year limited warranty
- Not as sophisticated as pricier models
- No germ-killing feature like the GermGuardian products offer
- Cannot turn off light indicators on panel
- Styling is more bland
Overall, it’s a very good budget air purifier that’s a great combination of price, performance, and features.
I’ve enjoyed mine and I’m sure you will, too! Be sure to check out the great buyer reviews at Amazon.
Want one of today’s top new air purifiers? Have a look at my review of the Levoit Core 300 here.
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