Keystone KSTAD50B Review


  • Very good value
  • Highly energy efficient
  • Comes equipped with a defrost mode for low temperature operation
  • Very light for superior portability


  • Gravity drainage requires adapter with screws
  • Small water tank

Included With Your Purchase

  • Dehumidifier
  • Gravity Drainage Adapter and Screws
  • Instruction Manual

Quick Review Summary

The Keystone KSTAD50B is a very good alternative to the top rated but more expensive Frigidaire FFAD5033R1. It draws less power and it’s also slightly faster at removing moisture, although it isn’t as quiet as the Frigidaire. Like the Frigidaire it has also received very few negative consumer reviews.

That being said, while the Keystone did perform slightly better than the Frigidaire in most of our performance tests, the difference between them was far from substantial. These dehumidifiers performed very similarly in most tests. They also have very similar features and functionality. The difference between them primarily lies in build quality and price. The biggest positive for the Frigidaire, in our opinion, is the fact that it’s a much more well built dehumidifier. It’s constructed using more high quality materials – the plastics making up its exterior shell and water tank are of a higher quality and its control panel is also of much higher quality. The biggest positive for the Keystone is the fact that it’s a much less expensive dehumidifier. It’s almost $50 cheaper than the Frigidaire. The question then becomes, “is this $50 price difference worth it? Is the Frigidaire worth paying $50 extra for?”

The answer is both yes and no. The answer is no because we are dealing with the 50 pint size class which is, by definition, a more budget oriented size class. 70 pint dehumidifiers are more heavy duty and generally more expensive while 50 pint dehumidifiers are less heavy duty and generally less expensive. Thus, if you’re looking to buy in the more inexpensive size class it only makes sense to buy a less expensive dehumidifier within that size class – the Keystone KSTAD50B.

The answer is also yes in the sense that the Frigidaire simply is the better more durable and therefore reliable dehumidifier. While it is $50 less expensive you’re still making a sizable investment if you buy the Keystone – it costs a substantial amount of money even though its priced very competitively at $170. In an empirical sense, the Frigidaire only needs to last 30% longer for it to be worth its 30% larger price tag and our shorthand opinion (after testing and inspecting both units) is that it definitely will.

Again, we want to make it clear that while the Frigidaire is the top rated dehumidifier in the category, the Keystone really is a good solid alternative – it certainly isn’t a bad dehumidifier. We suggest you read our full review below and decide for yourself whether you want to save the $50 and buy the Keystone, or invest $50 more and purchase the Frigidaire.

Performance Test Results

Energy Efficiency

The Keystone is one of the most energy efficient 50 pint dehumidifiers we tested. It was tested to draw 439 watts of power at approximately 50% relative humidity. Compare this measured power draw to the measured 493 watts of power draw for the top rated Frigidaire FFAD5033R1 under the same conditions. The average for all of the 50 pint dehumidifiers we tested is 457 watts.

At higher humidity levels (close to 100% RH) this unit will draw closer to the manufacturer specified 520 watts of power. Here its advantage over the Frigidaire is less pronounced as the FFAD5033R1 is rated by the manufacturer to draw 530 watts of power at maximum humidity. The average manufacturer specified power draw for all of the 50 pint dehumidifiers we’ve tested thus far is 525 watts.

Compared to its 70 pint counterpart the KSTAD50B draws approximately 28% less power (the KSTAD50B is rated at 520 watts and the KSTAD70B is rated at 720 watts) but takes almost twice as long to dehumidify the same space from 90% to 40% relative humidity, as was demonstrated in our own hands on testing (the KSTAD50B took 18:26 and the KSTAD70B took 11:04). Thus, while the KSTAD50B draws less power per unit of time, it needs to run for much longer to dehumidify any particular space from a higher humidity level to a lower humidity level. This slower moisture removal rate more than offsets its power draw advantage which makes the 70 pint version of the KSTAD50B the more energy efficient dehumidifier overall. We discuss how and why 70 pint dehumidifiers are more energy efficient than their 50 pint counterparts in greater detail here.

Noise Output

The KSTAD50B was an average performer in our noise output tests – it isn’t the most quiet 50 pint dehumidifier we tested but it’s also not the loudest. At closer range (sound meter placed above the dehumidifier’s control panel) the Keystone performed above average. This, however, was mostly due to the fact that it exhausts air out of its side, while those dehumidifiers which were measured to be louder in this test exhaust out of top of the dehumidifier (most of the measured noise is fan noise which makes the location of the exhaust fan a big factor in measured noise output at close range – we discuss this in greater detail here).

At long range (in which fan location isn’t nearly as much of a factor in noise output measurements), the KSTAD50B’s performance was less impressive. It placed in 6th (out of the eight 50 pint dehumidifiers we tested) on high fan speed and 5th on low fan speed. Out of all of the noise output tests we perform, the long range test (in which the sound meter is placed 10 ft away from the dehumidifier) with the dehumidifier set to low fan speed is most indicative of how quiet a particular dehumidifier can be in a real world setting. If you want your dehumidifier to run as quietly as possible you’re going to place it as far away as possible from you to reduce audible noise (long range) and you’re also going to put it on the setting which produces the least noise (low fan speed). Again, the Keystone placed 5th out of the eight 50 pint dehumidifiers we’ve tested in our long range test on low fan speed. The top rated Frigidaire FFAD5033R1 (click to read our review) placed 1st and is the better option if noise output is important to you and you’re looking to buy a 50 pint dehumidifier.

We do want to note here that 50 pint dehumidifiers, in general, are not much quieter than their 70 pint counterparts. The same is true for the KSTAD50B compared to the KSTAD70B. In fact, the KSTAD70B we tested was actually more quiet than the KSTAD50B we tested. At long range on low fan speed the KSTAD70B was measured at 48.1 dB while the KSTAD50B was measured at 48.8 dB. On high fan speed at the same range the 70 pint unit was measured at 49.9 dB while the 50 pint version was measured at 51.9 dB. For complete tabulated data click here.

Moisture Removal

The KSTAD50B removes moisture at an average rate for its size class. To test moisture removal rate we conducted two different tests. In the first test we measured the time it took each dehumidifier to dehumidify a 50 sq ft room from 90% relative humidity (severe humidity) down to 40% RH. In the second test we measured the time it took for each dehumidifier to dehumidify the same space from 80% RH (a less severe humidity level) down to 50% RH.

In the first test (90% to 40%) the KSTAD50 placed 6th out of the eight 50 pint dehumidifiers we tested. It took 18 minutes, 26 seconds. Compare this result to the 15 minutes, 31 seconds it took the top performing Danby DDR50A2GP. In the second test (80% to 50%) the Keystone placed 5th. It took 8 minutes, 56 seconds. Compare this result to the 7 minutes, 11 seconds it took the top performing Danby. Note that while the time difference is substantial between the Keystone and the top performing Danby, the Keystone’s performance in both tests was very close to average. The average for all 50 pint dehumidifiers in the first test was approximately 17 and a half minutes and the average for the second test was approximately 8 and a half minutes. Also note that the top performing Danby DDR50A2GP is unfortunately no longer readily available for sale at reputable merchants. You can still buy it but at an unreasonably high price.

Also, as we stress in other 50 pint dehumidifier reviews, moisture removal rate should not be a priority for you if you’re looking to purchase a 50 pint dehumidifier. 70 pint dehumidifiers are not much more expensive and they remove moisture at a much faster rate than their 50 pint counterparts. That is not to say that moisture removal rate should be a non-factor in your purchase decision. You don’t want a dehumidifier with a moisture removal rate that deviates too far from the mean. The Keystone does not – it does just fine for its size class.

Hygrometer Accuracy

The Keystone has a very accurate built-in hygrometer. The dehumidifier’s built-in hygrometer determines the ambient air’s humidity level and cycles its compressor on or off depending on whether that humidity level is above (compressor cycled on) or below (compressor cycled off) the set humidity level. The Keystone’s hygrometer was measured to read the ambient air’s humidity no worse than within 1% of the actual room humidity. For tabulated data covering each 50 pint dehumidifier’s performance in our hygrometer accuracy test click here.

Included Features, Functionality, Build Quality, Warranties, and Value


In assessing the durability of any particular dehumidifier we use the combination of our own observations and consumer feedback. Our own observations tell us the general build quality and the quality of the materials used to construct the dehumidifier while consumer reviews tell us the reliability of the dehumidifier over the course of several months and years of use (we only have any particular in our possession for about a month and during that time we only run it for testing).

For comments regarding this unit’s build quality see our KSTAD70B review as it is essentially the same dehumidifier – the one major difference being that it’s rated to remove 20 more pints of moisture per day.

Consumer Feedback

The KSTAD50B is a fairly popular dehumidifier with over 400 consumer reviews at the time of this editorial review. Of the 400+ reviews only 9% are 1 or 2 star – these reviews normally indicate a problem with reliability although they can also have to do with other issues. Compare this 9% negative review rate to the negative review rate of 5% for the top rated Frigidaire FFAD5033R1 and the 12% average negative review rate for the 50 pint size class (among the eight 50 pint dehumidifiers we’ve tested).

Durability Summary

The Keystone KSTAD50B is a well reviewed dehumidifier. In our KSTAD70B review we stated that our own observations made us question the dehumidifier’s overall build quality but we couldn’t argue with overwhelmingly positive consumer reviews (the KSTAD70B’s negative review rate is 11% compared to the 19% average for the 70 pint size class). The same is true for the KSTAD50B. It’s not nearly as well built and of the same high quality materials as the top rated Frigidaire, but it does have a well below average negative review rate which indicates well above average reliability. Just like we did for the KSTAD70B, we give the KSTAD50B an above average score for durability, mostly based on its outstanding consumer reviews.

Feature Summary

The KSTAD50B has all of the same features and all of the same functionality as its 70 pint counterpart, the KSTAD70B. For in-depth analysis covering these features and functions please see our KSTAD70B review. For the rest of this review we’ll only briefly summarize this unit’s most important features and functionality.

The Keystone KSTAD50B features 2 fan speeds (compared to the 3 on the Frigidaire) and a continuous mode (like the Frigidaire). It has a set humidity range of 35 to 85% which exactly mirrors that of the Frigidaire. It does feature gravity drainage but requires an adapter (included with your purchase) just like the Frigidaire, the major difference being that the Keystone’s adapter comes with screws while the Frigidaire’s adapter is threaded for a much simpler installation.

One big advantage the Keystone has over the Frigidaire is the fact that it comes equipped with a defrost mode while the Frigidaire does not. This is a very useful feature if you plan on operating the dehumidifier in colder temperatures. Defrost mode automatically shuts off the dehumidifier’s compressor when frost builds up on its evaporator coils. It allows the fan to continue to run to melt the frost. Once the frost is melted the compressor cycles back on. If a dehumidifier does not come equipped with a defrost mode and you operate it at lower temperatures you have to manually monitor the dehumidifier’s efficiency. If you notice its efficiency dropping (condensate starts to collect at a lower rate than usual) then you have to manually turn off the dehumidifier to allow the frost to melt. The takeaway here is that if you plan on operating your dehumidifier at lower temperatures then you definitely want to take the fact that the Keystone comes equipped with a defrost mode into consideration in comparing it to the top rated Frigidaire.

One big disadvantage the Keystone has compared to the Frigidaire is the size of its water tank. The Keystone has a smaller than average 10.4 pint tank while the Frigidaire has a larger 13.1 pint tank. The Keystone’s smaller tank means that you’ll be emptying it more frequently.

Both the Keystone and the Frigidaire (and both of their 70 pint counterparts) come with a full 1 year warranty and an additional 2-5 year warranty on the dehumidifier’s compressor, condenser, its evaporator, and any sealed tubing.

Portability (Weight)

If portability is important to you then either the KSTAD70B or the KSTAD50B is a good option. Both dehumidifiers have below average weight for their respective size class. The KSTAD70B weighs 40 pounds and the KSTAD50B weighs slightly less at 36.3 pounds. The KSTAD50B is a substantial 9+ pounds lighter than the FFAD5033R1 which weighs in at 46 pounds. It’s only 2.3 pounds heavier than the 30 pint Frigidaire FFAD3033R1 which weighs 34 pounds.


The KSTAD50B is the least expensive 50 pint dehumidifier we’ve tested and probably the least expensive 50 pint dehumidifier on the market. It retails for about $170. Compare this price to the approximately $215 retail price for the Frigidaire FFAD5033R1 and an average price of approximately $210 for all of the 50 pint dehumidifiers we’ve tested.


Final Thoughts

The Frigidaire FFAD5033R1 is the best 50 pint dehumidifier we tested. The Keystone KSTAD50B is not the best but it’s still a very good 50 pint dehumidifier. It’s also the less expensive dehumidifier. We rated the Frigidaire as the best 50 pint dehumidifier and the Keystone as the second best mostly because the Frigidaire is the more durable and therefore the more reliable dehumidifier. If you want the best most reliable 50 pint dehumidifier then the Frigidaire is the best choice. If you want the best 50 pint dehumidifier under $200 then the Keystone is highly recommended. You really can’t go wrong with either dehumidifier.

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