Keystone KSTAD504D Review



  • Good energy efficiency
  • Above average performance in our moisture removal tests
  • Light and quite portable for a 50 pint dehumidifier


  • Loud compressor
  • Below average hygrometer accuracy
  • Below average build quality
  • Adapter and screws required for gravity drainage

Included With Your Purchase

  • Dehumidifier
  • Gravity drainage adapter and two screws
  • Instruction Manual

The Keystone KSTAD504D is not the best dehumidifier. But, it’s often priced much lower than top rated options.

The question, then, is can you put up with the Keystone’s shortcomings if that means paying much less than you would for a top rated dehumidifier?

We hope to answer that question in the review below.

Performance Test Results

Energy Efficiency

The Keystone KSTAD504D was one of the more power hungry 50 pint dehumidifiers we tested. It had a measured power draw of 596 watts. Most other 50 pint units we tested had a measured power draw closer to 570 watts.

Maybe because of its slightly higher power draw, the Keystone was an above average performer in our moisture removal testing. It took less time than most other 50 pint units we tested to lower room humidity in our test space.

Thus, we can say that this unit offers slightly above average energy efficiency despite its above average power draw. Yes, it does draw slightly more power but it dehumidifies much faster than most other 50 pint units we tested and so it is more efficient than most other 50 pint units.

Noise Output

The KSTAD504D was one of the noisiest 50 pint dehumidifiers we tested.

The main culprit? Its compressor noise. All 50 pint units we tested exhibited some type of compressor noise but this Keystone unit maybe had the loudest compressor of them all.

The unit does make quite a bit of fan noise which covers up the compressor noise to some extent. But, overall, compressor noise still filters through and it’s not pleasant to listen to.

Moisture Removal

As we mentioned earlier, this unit was an above average performer in our moisture removal tests.

In the first test, in which we measure how long it takes the unit to lower room humidity from 90% down to 40% relative humidity (RH) in a 50 sq. ft. space, the Keystone placed fourth among the 11 high capacity units we tested most recently. It took 10 minutes, 1 seconds in the test – 2 seconds faster than the top rated hOmeLabs HME020031N. The fastest time in this test belongs to the Frigidaire FFAD5033W1 with a time of 7 minutes, 56 seconds.

In the second test, we measure the time taken to lower room humidity from 80% down to 50% RH. Here the Keystone placed sixth with a time of 5 minutes, 41 seconds. The top rated Frigidaire had a time of 5 minutes, 19 seconds and the hOmeLabs had a time of 5 minutes, 33 seconds.

Hygrometer Accuracy

During testing, the Keystone’s displayed humidity level varied from being within 2% of the actual room humidity to within 6% of the actual room humidity.

Compare this result to top rated units which always read room humidity to within about 2% of the actual room humidity.

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

Durability (Build Quality)

General Impressions

The Keystone KSTAD504D is a budget dehumidifier. And it shows. This unit very obviously features below average build quality and lower grade materials than what you find on top rated units.

The Keystone also has a very dated design. We tested and reviewed the KSTAD70B several years ago and the KSTAD504D is essentially the exact same dehumidifier. The KSTAD504D’s control panel feels especially dated (modern units have better quality buttons and a better quality LED display).

Consumer Feedback

The KSTAD504D is fairly new to market and so hasn’t received any consumer feedback as of the writing of this editorial review.

Overall Category Score

This is not a durable dehumidifier. It earns a below average 3/5 in the category.



The Keystone has a humidistat that can be set in 5% increments.

It has a timer than can be set for up to 24 hours.

It has 2 fan speeds, a continuous mode, and an automatic mode.

All of these (except auto mode – more on this in the next section) are standard features in the industry.

Overall Category Score

The unit earns an average 3.5/5 in the category.


Set Humidity Range

The Keystone has a set humidity range of 35% to 85%. In other words, you can set it to between 35% and 85% (in 5% increments) and it will lower room humidity to match that setting. Note that here you’re setting a desired humidity level manually.

Auto mode chooses a desired humidity level for you – what the manufacturer believes to be a comfortable level for most users. Otherwise, the unit works exactly the same as it does on manual mode.

Operating Temperature Range

The manufacturer does not specify an operating temperature range for this model (at least according to our research). But it’s safe to assume this unit’s range is much the same as every other compressor based dehumidifier we tested – between 41° F and 90° F.

Gravity Drainage

This unit requires that you install a plastic adapter with two screws to employ gravity drainage (see photos below).



Most other 50 pint units we tested allow you to connect a garden hose directly to the back of the unit without needing to install an adapter first.

Built-in Pump

This unit does not have a built-in pump.

Overall Category Score

The Keystone earns a below average 3/5 in the category.

Extra Features

Temperature Reading

This unit’s control panel does not show ambient room temperature.


This unit does offer a defrost mode and a defrost indicator light.

Check Filter

This unit does display a check filter warning, when it’s necessary to clean the filter.

Overall Category Score

The Keystone earns a 4.5/5 in the category.

Ease of Use

LED Display Clarity

The unit’s LED display is poor quality.

Setup Difficulty

The unit’s buttons and indicator lights have clear text labels. Operation is easy enough that you likely won’t even need to reference the unit’s manual.

Filter Removal Difficulty


The air filter pulls up and out of the front of the unit. Filter access couldn’t be easier.

Manual Clarity

The unit’s manual is poorly written and illustrated. Thankfully, you won’t need to use it much as the control panel is labeled well enough.

Water Tank Size


The unit’s water tank has a capacity of only 1.6 gallons, or 12.8 pints. The average for the 50 pint size class is closer to 14 pints. Some 50 pint units have an especially large tank. The Frigidaire FFAD5033W1, for example, has a 16.9 pint tank – over 4 pints larger than the Keystone’s tank.

All other things being equal, a larger tank requires you to empty and replace it less frequently. Smaller tanks fill up faster which means you have to empty and replace them more frequently.

Overall Category Score

It’s poorly written manual and small water tank gives the Keystone a below average 3/5 in the category.


The Keystone KSTAD504D is one of the lightest 50 pint dehumidifiers on the market, weighing in at only 40 lb. Most other 50 pint units weigh upwards of 43 to 45 lb. Such is the case for the top rated Frigidaire FFAD5033W1, which weighs 43 lb. exactly by comparison.

The Keystone features side pocket handles, just like most other 50 pint units on the market. A few units, like the FFAD5033W1, have a top extendable handle that does make the dehumidifier slightly easier to pick up and move around than units like the Keystone with side pocket handles.

The KSTAD504D has a plastic band on the back that you can use to tie down its power cord. It’s certainly not the most elegant cord storage solution but it does work as intended. Certain models, like the LG UD501KOG5 for example, offer no cord storage at all so you have to awkwardly hold their power cords yourself when moving them around.

Overall Category Score

The Keystone is light and sufficient cord storage to make it quite easy to move around. It earns an above average 4.5/5 for portability.

Warranty (Manufacturer’s)

The KSTAD504D we bought for this review came with a 1 year warranty with an additional 2-5 year warranty on its sealed system (compressor, condenser, etc.).

This used to be the industry standard warranty – 1 year plus 4 additional years on the sealed system.

Today, that is no longer the case. Most dehumidifiers – even the top rated Frigidaire FFAD5033W1 – come with only a 1 year warranty. There is no additional coverage for the sealed system.


The KSTAD504D is a budget dehumidifier with a budget price. If it were better built with better performance in our noise output and hygrometer testing, it would be a good value at its budget price. But it’s not. It’s poorly made with poor performance in important tests, and so it’s at best an average value at its budget price (and that is if you can find it at a budget price – it’s not always priced the same).


  1. Russ Graff says

    What is customer service contact information. Have a new unit with operation question. – it does not generate water in collection bucket.

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