Hands-on Gear Review

GermGuardian AC4825 Review

Best Buy Award
Price:   $100 List | $83.39 at Amazon
Pros:  Low operating costs, good air cleaning performance
Cons:  Relatively loud
Bottom line:  A great combination of good performance and low operating cost make this a great budget option
Editors' Rating:   
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Dimensions:  6.75" x 10" x 21.75"
Weight:  8.4 lb
CADR:  122 CFM
Manufacturer:   Guardian Technologies

Our Verdict

If you're looking for an inexpensive way to get some pollen out of your house, look no further than the GermGuardian AC4825. For only $100 up front and less than $100 per year over its lifetime the GermGuardian AC4825 can provide good air cleaning performance for any room in your home. If you're looking for a cheap option for infrequent use the GermGuardian AC4100 may be a better option, but if you're looking for a low cost all year or allergy season workhorse the AC4825 is your best bet. The only real downside: it's a bit loud. Not Terribly loud, but if you're sensitive to noise you may want to consider paying a bit more for the ultra quiet Coway Ap-1512HH.

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Our Analysis and Test Results

Review by:
Max Mutter and Steven Tata

Last Updated:
July 8, 2017


The GermGuardian AC4825 provides reasonably good performance at a low price, making it a great choice for those that want some pollen help without breaking the bank.

Performance Comparison

The GermGuardian AC4825 was middle of the pack in terms of overall performance, but was by far the best of the models in its price range.

Below we discuss all of the individual testing metrics that, when combined, make up our overall scores and how the GermGuardian AC4825 performed in each.

Air Cleaning Performance

The GermGuardian AC4825 was right around average in our air cleaning tests, earning a score of 6 out of 8.

The GermGuardian AC4825 performed quite well in our air cleaning testing. After 30 minutes in our smoke filled testing room it reduced airborne particulates by 99.22%. The top performers were above 99% at this point in the test, so the AC4825 did lag a bit behind, but not by much. At the hour mark it had brought airborne particulates down by 99.32%. The top performer hit 99.84% at the same point, so the AC4825 was incredibly close.

The AC4825 lost some points because of its relatively low CADR (clean air delivery rate) of 122. This generally makes it suitable for rooms of up to 183 square feet, which is likely smaller than many living rooms. That's not to say it wouldn't do anything in a larger room, it would just take longer to get rid of particulates and may not ever get concentrations quite as low as it would in a smaller room. No model performed well in reducing odors, and the AC4825was about average in that capacity as well. It reduced smoke odors in our testing an appreciable amount, but we could still smell quite a bit of smoke.


If you're sensitive to noise and hoping to get an air purifier on the cheap you may be out of luck. We found that the biggest sacrifice you make with inexpensive models is that the fans are much more audible. The AC4825 is no exception, it was one of the loudest models we tested.

That isn't to say that the AC4825 is a roaring dragon that's going to turn your living room into an unbearable cacophony. Its fan noise is just much more noticeable than most. Enough so that you may end up cranking your TV's volume a few clicks farther up than normal. On high the fan makes a high pitched squeal that is hard to ignore, and doesn't blend into the background as well as other machines. Putting it down to a medium setting lowers the volume a little bit, but the pitch is still high and noticeable. On low settings the pitch is still high, but quiet enough that it will likely fade from your awareness after a few minutes.

The AC4825's fan is a bit on the loud side.
The AC4825's fan is a bit on the loud side.

Ease of Use

The AC4825 was again about average in our ease of use testing. It was by no means difficult to use, but not quite as streamlined as the top scorers.

The AC4825 uses a simple dial to switch between its three fan speeds. There is also an option to turn on and off its UV lamp with the press of a button. This lamp is meant to kill airborne bacteria, but the verdict is still out on the effectiveness of such devices. This is a simple, intuitive interface, but most models offer additional features that make them a bit more usable. For starters, most have at least four fan speeds. Most also have off timers so you can turn them on before you go to bed and not have to remember to turn them off before you leave for work. Because the AC4825 doesn't have these kinds of features, it lost a few points. It is very light at 8.4 pounds, making it easy to carry around, even though the carry handles are somewhat awkwardly designed.

The AC4825 opts for a very simple control panel.
The AC4825 opts for a very simple control panel.

Operating Cost

Our estimated lifetime cost for the AC4825 came out to $455, more than $100 less than the average.

The AC4825 is one of the more power hungry models we tested, requiring 0.04 kWh of electricity to run for one hour. Over a year that would amount to a cost of about $21.02 assuming average electricity rates. However, it makes up for this with very inexpensive filters that last 7 months and only cost $30. It's list price is also fairly low at $100. This pushed its estimated lifetime cost well below the average.


The AC4825 is both a great deal up front and in the long run. The $100 list price is relatively low for a large purifier, and its inexpensive filters keep the lifetime costs below $500. This works out to less than $100 per year over its lifetime. This makes it a great value if you're going to be using it consistently, and earned it our Best Buy Award. If you're looking for a unit to occasionally use in a small bedroom for guests, the GermGuardian AC4100 may be a better choice.


If you're looking for an inexpensive air purifier to use throughout the year or for the entirety of allergy season the GermGuardian AC4825 is a great choice. Low operating costs and good air cleaning performance combine to create an effective and relatively inexpensive device.

Max Mutter and Steven Tata

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