GermGuardian AC4020 Air Purifier: Trusted Review & Specs

The GermGuardian AC4020 is not the best seller for budget device of Guardian Technologies anymore, the GermGuardian AC4100 has claimed the title. Still, the price is even cheaper, and you can’t get this device out of your head? So let’s read our GermGuardian AC4020 Review to decide.

Updated: The GermGuardian AC4020 has been discontinued, so I recommend you to look for the GermGuardian AC4200, which is a newer model from the Guardian Technologies.

GermGuardian AC4020 ranks D+ in our air purifier ranking list. We give the biggest and most thorough database of air purifier reviews in the world.

In Breathe Quality, we have reviewed all air purifiers under these sections. Also, we guarantee that:

  • We provide honest reviews (both pros and cons) so that everyone can make the best decisions.
  • We do not (and never) exaggerate one product just to let you click the links and buy that product blindly.


germguardian ac4020 review

  • Cheaper price
  • A combination of HEPA and UV-C light for the price

  • Quite noisy at highest setting
  • Lacks of Smart features
  • Discontinued

Guardian Technologies continues to be the king of budget air purifiers in North America. As the Entrepreneur of the Year, we can believe this American brand will repeat its success over the years. The GermGuardian AC4020 is an old device from its army, but it is still the best seller, thanks to its most affordable price. Okay, let’s dig deep in our GermGuardian AC4020 Review.

Other GermGuardian’s Air Purifier Reviews:

GermGuardian AC4020 Price

Price for the GermGuardian AC4020 is even much lower than the budget GermGuardian AC4100 and GermGuardian AC4150. Still, this air purifier is the basic option for a combination of both HEPA filter and UV-C light filter. Of course, you will have a much inferior HEPA filter.

You can find the GermGuardian AC4020 in local stores for only $49, or you can get it with our deal below. The price is at least $10 cheaper than the official price tag of AC4100 or new GermGuardian AC4200, but you should check this air purifier because it always has good deal.

For the price, this GermGuardian AC4020 is cheaper than even the Hamilton Beach 04384, Levoit LV-H126, Honeywell HHT270W, and even the new Levoit LV-H128.

Top GermGuardian AC4020 deals right now

GermGuardian AC4020 3-in-1 Portable Air Purifier with High Performance Allergen Filter and UV Sanitizer.

High Performance Allergen Filter reduces dust and allergens down to 0.3 microns. UV light technology works with Titanium Dioxide to kill airborne bacteria, viruses, germs and mold spores.

Related post: Best air purifier 2023.

GermGuardian AC4020 Design and Size

The GermGuardian AC4020 is the budget version of the GermGuardian AC4100, and sports the same design concept as its bigger brother. I personally like the uncluttered design, with the only one manual knob and air grill for the whole front. You can’t mistake it with other electronic appliances.

The whole body is made out of plastic, and this air purifier is 2-inch shorter than the AC4100 and GermGuardian AC4150, with only 9 inches in height. And the weight is only 3.65 lbs, making this GermGuardian AC4020 one of the most lightweight air purifiers, only a bit heavier than the Blue Pure 411 with 3.4 lbs, or SilverOnyx 3-in-1 with 2.9 lbs.

Besides these things, the GermGuardian AC4020 is identical to the GermGuardian AC4100 from everything. You will get the same airflow system concept, with a full-size air intake grill behind and another full-size air outlet grill from the front. It also uses the small perforated holes to act as a pre-filter.

And yes, you will only have one manual switch to control this air purifier. Look from behind, you can see a manual filter replacement indicator of this GermGuardian AC4020.

germguardian ac4020 review


Related post: Best air purifiers for bedroom.

GermGuardian AC4020 Filters

For an under $50 air purifier, we weren’t expecting much in the performance department. You will enjoy the only 2-stage air cleaning system of the GermGuardian AC4020, also the most budget air purifier of this brand.

  1. High Performance Allergen Filter – This is actually the combination of a HEPA filter and Activated Carbon filter to capture 99% of dust and allergens in the air, while reduce common odors from pets, smoking and cooking. The carbon layer covers the HEPA filter, and can reduce most of the larger objects first.
  2. UV-C Light – The unique 2W bulb with UV-C light to fight germs, kills airborne bacteria, viruses and mold spores.

Instead of separating Activated Carbon and HEPA filter to 2 physical layers, GermGuardian AC4020 combines these two to reduce the air filter’s size and increase the space within this air purifier. With only the HEPA-type filter, GermGuardian AC4020 can’t guarantee the high efficiency like any air purifiers with the certified True HEPA filter. Looking into the below chart, you can see this GermGuardian AC4020 has the lowest efficiency if compared with the Levoit LV-H132, and then maybe Blue Pure 411, AeraMax 100 or GermGuardian AC4825.

germguardian ac4020 review

The GermGuardian AC4020 uses an unique air filter named FLT4010 Filter A, which has the most affordable price of only $17. You should change the air filter every 6 to 8 months, and I hope that you check the manual filter replacement indicator behind your GermGuardian AC4020.

Related post: Best air purifiers for allergies.

GermGuardian AC4020 Room Coverage

For a table top air purifier, GermGuardian AC4020 can only deal with the room of 100 square feet. This is exactly how the GermGuardian AC4100 and GermGuardian AC4150 can do.

The ACH of GermGuardian AC4020 is only 2X. This compact air purifier will clean your room every 30 minutes.

The CADR of GermGuardian AC4020 is 66 Dust/ 50 Smoke/ 76 pollen (cfm).

Related post: Best large room air purifiers.

GermGuardian AC4020 Sound

Just like the GermGuardian AC4100, this GermGuardian AC4020 has only 3 fan speeds. And it doesn’t produce any sound on the lowest setting.

Unfortunately, this air purifier has a high pitched moan while running on high setting. And more importantly, it is hard to ignore. That’s why, GermGuardian AC4020 is clearly not the best option for quiet places, such as the office or bedroom.

For a quieter air purifier, you can look for the GermGuardian AC4150, costing only more than $20.

Related post: Best air purifiers for baby.

GermGuardian AC4020 Power Consumption

To be one of the best air purifiers, one device must strictly pass our Breathe Quality test after a long time use. Also, one of the most asked questions in Breathe Quality is: “Do air purifiers use a lot of energy?”. We can all agree that power consumption is one important criteria to review if this air purifier is worth your money or not.

Using an only 2 watts UV-C bulb, GermGuardian AC4020 has a truly energy-saving power consumption of 40 watts. The power consumption is not as great as Levoit LV-H132 or Blue Pure 411, but is still acceptable for a compact air purifier.

For using a GermGuardian AC4020 8 hours per day, it would cost you up to $15 per year.

Related post: Best air purifiers for pets.

GermGuardian AC4020 Additional Features

GermGuardian AC4020 is still an old air purifier from this family, so just like the GermGuardian AC4100, it doesn’t have any additional features, not even the LED indicator for filter replacement. If you want more features, especially a Smart Sensor for this price, you should look for the AeraMax 100 or Levoit Core 200S.

It is also superseded by the latest GermGuardian CDAP4500BCA which is released in 2017, so you should not expect much from an under $50 air purifier.

Related posts:

1, Best air purifiers for smoke.

2, Best air purifiers for dust.

3, Best air purifiers for mold.

GermGuardian AC4020 Customer Service

There is not much to say about the brilliant support from Guardian Technologies’ customer service. Anyone can get active support from the American brand. The company also makes the instruction manuals available online to help you answer common questions on your own. But if you can’t find a solution, just contact customer service via phone at 866-603-5900 or via email at Just like any other brand, the office will be open from Monday to Friday.

Guardian Technologies occasionally offers free shipping as well as a significant discount on all products (typically 10% to 20%). Whenever you find the air purifiers are not as great as you had thought, you can return them within 30 days of your original receipt of the order. And don’t worry about the warranty policy of Guardian Technologies, as it warrants its products to be free of defects in materials or workmanship. You can register for a warranty for up to five years.

However, for the GermGuardian AC4020, you will only have an 1-year warranty.

Top GermGuardian AC4020 deals right now

GermGuardian AC4020 3-in-1 Portable Air Purifier with High Performance Allergen Filter and UV Sanitizer.

High Performance Allergen Filter reduces dust and allergens down to 0.3 microns. UV light technology works with Titanium Dioxide to kill airborne bacteria, viruses, germs and mold spores.

Our verdict

I can’t differentiate this GermGuardian AC4020 and GermGuardian AC4100, except for a slight change in the size. So the only thing to decide which one to choose is the price.

However, its performance is low, and its overall ranking is D+, so we can’t recommend this air purifier. And it is discontinued, so make sure to check other Guardian Technologies’ air purifiers, for example the GermGuardian AC4200.

GermGuardian AC4020 Air Purifier: Trusted Review in 2024
GermGuardian AC4020 Air Purifier: Trusted Review & Specs

GermGuardian AC4020 Reviews and Specs (Air Purifier Trusted Reviews in 2024). ✓ Cleaning Power: HEPA + UV-C filter ✓ Size: 4 lbs ✓ Value: 2.4/5 ✓Certified Review.

Product Brand: Guardian Technologies

Product Currency: USD

Product Price: 49

Product In-Stock:

Editor's Rating:
  • Performance
  • Features
  • Annual Cost
  • Design
  • Price


We don’t recommend this air purifier. Even for low budget.