AirDoctor AD3500 air purifier review

HEPA filters can remove at least 99.97% of airborne particles measuring just 0.3 microns, including some mold spores and pollutants from tobacco smoke. Once a premium feature, they are slowly becoming the norm, and even some of the most affordable of the best air purifiers have HEPA filters these days. No wonder, then, that lesser-known brands are stepping up their filter game to stand out from the crowd. AirDoctor, also known as AmazingAir in the U.K., is a good example of that constant market evolution.

All of AirDoctor’s air purifiers are equipped with an UltraHEPA filter. This means that they can capture at least 99.99% of airborne particles as small as 0.003 microns in size — 100 times smaller than a regular HEPA filter. AirDoctor air purifiers also have a pre-filter that catches large particles like dust and hair and a dual-action carbon/VOC filter that traps odors and volatile organic compounds. On top of that, their jet fans are deemed to be 30% quieter than the fans used in traditional air purifiers.

Intrigued by these impressive specs, we tested the AirDoctor AD3500, the most popular model in the brand's line-up. Given that this model can cover up to a whopping 1,260 square feet (117 square meters), it has the potential to be our top pick for large rooms and commercial premises.

AirDoctor AD3500 air purifier review

AirDoctor AD3500: Design

• Ultra-light and portable for the unit's size
• Basic, uninspiring design
• Intuitive control panel with dimmable indicator lights

The AirDoctor AD 3500 did not impress us with its appearance. With its rectangular shape and white, glossy surface, we thought it looked more like a mini fridge than an air purifier. However, this ultra-basic design has some advantages. If you do not want your air purifier to draw much attention, the AirDoctor AD 3500 will be right up your street. Its indicator lights can be switched off when needed, and its control panel is very intuitive to use, too.

We also liked its light and portable frame. The AirDoctor's AD3500 weighs 18 pounds (8.16 kg), which is surprisingly little for an air purifier that can cover up to 1,260 square feet (117 square meters). When we first picked it up (which can be easily done thanks to two deep ridges conveniently located on the sides), we even questioned whether we may have received a faulty unit. But no, the AD3500 really is that light. It is a great option if you lack strength or need to move the unit around frequently.

In addition, the AirDoctor air purifier is easy to clean and maintain. It has no deep crevices or awkward protruding elements, and the filters can be replaced in mere seconds thanks to a magnetically attached lid at the front of the unit.

Speaking of replacement filters, they are not cheap. AirDoctor charges a whopping $152.99 for a one-year supply — almost twice as much as most of its direct competitors. This is quite a big downside.

AirDoctor AD3500: Features

• Pre-filter, UltraHEPA filter and carbon/VOC filter
• Optional smart features
• Air particle sensor and auto mode

This air purifier is available in two options: with and without smart features. We tested the basic AirDoctor AD3500 model which has no Wi-Fi connectivity and costs $629.99. The smart-enabled option, the AirDoctor AD3500i, costs $50 more and offers features such as remote control, air quality readings and filter change alerts.

We liked this approach. Some people love high-tech frills, while others do not need or care about them, and it is rare to see a brand that caters to both of these groups simultaneously. Nevertheless, we still think both models are on the expensive side.

The AirDoctor AD3500 is equipped with three filters: a pre-filter to capture large particles like dust and pet hair, a carbon/VOC filter that removes odors and volatile organic compounds (VOCs), and an UltraHEPA filter designed to trap 99.99% of ultra-fine particles down to 0.003 microns in diameter. This air purifier also comes with an ionizer, built-in air particle monitor, auto mode and a timer. It is not the most feature-packed appliance we’ve ever tested, but it has everything you need — except smart features, that is.

AirDoctor AD3500 air purifier: Performance

• Great air-cleaning performance in ambient air tests
• Does an excellent job at removing smoke particles
• Relatively quiet, but its airflow can be disruptive

We were impressed by the performance of the AirDoctor AD3500. This air purifier appeared to do a good job at removing odors and airborne pollutants, making the air in our home tangibly easier to breathe. It was also relatively quiet. When we measured it with a decibel-counting Sound Meter app, we did not get a reading higher than 57 dB — equivalent to the sound levels generated by a refrigerator or a vacuum cleaner.

There is one caveat, though: The airflow in the AD3500 is very powerful. When this air purifier kicks into high gear, it almost resembles a tower fan. If you intend to keep it in your bedroom, you may want to place it at a considerable distance from your bed so it does not disturb your sleep. On the other hand, this strong airflow likely contributed to the excellent results we obtained in our tests using an industry-grade Perfect Prime air particle monitor.

We started with an ambient air test. We put the AirDoctor AD3500 in an enclosed, medium-sized room, took baseline air quality readings, then ran this air purifier on its auto settings for 15 and 30 minutes. The results were impressive. After 15 minutes, the AD3500 removed 85.4% of particles measuring 0.3 microns and 99.99% of pollutants measuring 2.5 microns (no 10-micron particles were detected). After half an hour, these values rose even further — to 91.5% and 100%, respectively. We obtained similar results when we repeated the test in a different room.

We got even better results during our smoke tests. First, we burned 10 matches, then we ran the AD3500 for 15 and 30 minutes on its auto setting. After 15 minutes, our AirDoctor had hoovered up a staggering 98.9% of 0.3-micron particles, 99.95% of particles measuring 2.5 microns, and all the pollutants larger than 10 microns. 15 minutes later, the air quality was comparable to the baseline measurements. When we did the match test on the highest setting, nearly all particles were gone after 15 minutes.

Next, we burned five incense sticks and repeated the procedure. The AirDoctor AD3500 trapped nearly all particles after 15 minutes, and just like in the match test, the air quality after 30 minutes returned to the baseline levels.

All in all, it is rare to see such a well-performing air purifier for under $700. The cherry on top? It is Energy Star-certified.

AirDoctor AD3500 air purifier: User reviews

Amazon's customer reviews gave the AirDoctor AD3500 a 4.7 out of 5 stars rating, with 84% of users giving it a full five stars. Positive reviews often praised this air purifier for its powerful air-cleaning performance, unobtrusive design and quiet jet fans. As one user said, "This one is the best bet for the cost, can clean a fairly large space, and can capture particles even finer than most other purifiers available. Yes, there are better units available, but they're going to cost at least twice as much. This unit outperforms everything else in its price point."

Negative reviews tended to revolve around acrid smells coming from the unit and poor customer service from the company. As one user commented, "I wanted to love this machine. The power to move the air was great but as soon as I opened the front to remove the plastic cover over the charcoal filter a strong chemical odor overtook me. It gave me instant sinus pain."

Should you buy the AirDoctor AD3500 air purifier?

✅ Buy it if: You are looking for a top-quality air purifier for large spaces and commercial premises. The AirDoctor AD3500 is ultra-light, portable and immensely powerful, but won’t put too much strain on the energy bill or make excessive noises. It comes with optional smart features, too.

❌ Don't buy it if: You want an air purifier suitable for small spaces, or are on a tight budget.

If AirDoctor AD3500 is not for you

The stylish Molekule Air Pro is an excellent alternative to the AirDoctor AD3500. Packed to the brim with high-tech features, this thoughtfully designed air purifier covers up to 1,000 square feet (92.9 square meters). However, the Molekule Air Pro is also very noisy, and at nearly $1,000, almost twice as expensive as the AD3500.

If you are looking for something cheaper, check out the Levoit Core 600S. This air purifier takes the top spot in our guide to the best air purifiers thanks to its ease of use, smart features and outstanding air-cleaning performance — and it costs just $299.99. However, it only covers rooms of up to 635 square feet (59 square meters).

Want something better looking? Then the RabbitAir A3 should be on your radar. This beautifully designed air purifier delivers excellent air-cleaning performance at a whisper-quiet level, and it covers up to 1,070 square feet (99 square meters). It does, however, carry a $749.95 price tag.

AirDoctor AD3500 air purifier: How we tested

We spent over two months testing the AirDoctor AD3500, looking at its design, features, day-to-day performance, ease of use and value for money. We also measured how loud this air purifier was on different fan speeds using a Sound Meter decibel-counting app.

Then, we conducted a series of performance tests using a Perfect Prime air particle monitor, a professional-grade device capable of detecting airborne pollutants as small as 0.3 microns. We started with an ambient air quality test: we put the AirDoctor AD3500 in an enclosed, medium-sized room and ran it on auto mode for 30 minutes, taking air quality readings every 15 minutes.

Next, we performed several smoke tests. We burned matches and incense sticks to create different types of heavy pollution, then recorded the changes in air quality readings before and after running the AirDoctor AD3500 for 30 minutes. The smoke tests were conducted on the maximum fan speed and auto settings.