SPT (also known as Sunpentown) manufacturers a variety of different air quality appliances, including compressor, desiccant and thermo-electric dehumidifiers. They manufacturer only two different models of thermo-electric dehumidifiers, the SD-350 and the SD-350TI. We compare these two dehumidifiers to each other and to the other six thermo-electric dehumidifiers we tested in 2015 throughout our review below.

Performance Test Results

Noise Output

Neither SPT unit performed very well in our close range noise output test. The SD-350′s measured noise output was 58.2 dB at close range (with the sound meter placed within a few inches of the dehumidifier). The SD-350TI’s measured noise output was 63.2 dB at the same range. The former (SD-350) placed sixth in this test (was the sixth quietest) while the latter (SD-350TI) placed dead last (eighth) among the eight thermo-electric dehumidifiers we tested. Compare these test results to the very quiet Gurin DHMD-210 which was measured to produce only 44.5 dB of noise at the same range. The average noise output at this range for the eight thermo-electric dehumidifiers we tested was 53.2 dB.

The bottom line is that neither SPT unit is a good option if noise output is a priority for you in purchasing a thermo-electric dehumidifier. The only part inside a thermo-electric dehumidifier that actually produces noise is a single fan that pulls air through the dehumidifier. Unfortunately, the fans used in the manufacturing of both the SD-350 and the SD-350TI are much louder than average. If you’re looking for a quieter option in the same price range as the SPT units (sub approx. $60), the aforementioned Gurin DHMD-210 and the Ivation IVADM10 are great options that were both measured to produce less than 50 dB of noise in our close range testing. Both the Gurin and the Ivation retail for only about $40 and both remove only approximately 4 oz. less moisture per day than either SPT unit.

Moisture Removal Rate

Speaking of moisture removal rate, both SPT units didn’t fare very well in our moisture removal tests either. In order to compare the moisture removal rate of the thermo-electric dehumidifiers we tested we didn’t want to only rely on manufacturer specifications. We wanted to test each unit ourselves for two reasons – one, to see how it would stack up against the competition and two, to see how our test results compare to manufacturer specifications.

With these goals in mind we placed each dehumidifier we tested in a 50 sq ft sealed test environment. We raised the humidity in the room past 80% RH (relative humidity) and then timed how long it would take each unit to dehumidify the room from 80% RH down to 70% RH. In having the initial room humidity above 80% RH we gave each dehumidifier what amounted to a “rolling start” as we started the timer when the room reached 80% RH. We only required that each thermo-electric dehumidifier we tested dehumidify the room down to 70% RH because requiring that any one of the units we tested dehumidify the room down to 40%, 50%, or even 60% RH would take too much time (depending on how low of a humidity level we required the room to be dehumidified down to it could take upwards of several hours for any particular thermo-electric dehumidifier to accomplish this feat).

We wanted to limit our trials to take no longer than approximately 20 to 30 minutes as each dehumidifier was subjected to at least three different trials and we had five different “large” thermo-electric dehumidifiers to test (the three mini thermo-electric dehumidifiers we tested were only required to dehumidify the room down to 75% RH). Thus, the parameters for testing were set at 80 to 70% RH.

Since both SPT units were among the five “large” thermo-electric dehumidifiers we tested, we’ll compare their test results to those of the other three “large” units we tested. Both the SD-350 and the SD-350TI took approximately 20 minutes (an average of several different trials) to dehumidify the room from 80% RH down to 70% RH. Compare this time to the 12 minutes it took the Ivation IVADM35 and the Ivation IVADM45. It took the Perfect Home EWDH4 just as long to dehumidify the room within these set parameters as both SPT units – 20 minutes.

Manufacturer Specified Moisture Removal Rate

As we outlined above, our own test results showed that both Ivation units remove moisture about twice as fast as both SPT units – it took each Ivation unit 12 minutes to dehumidify a 50 sq ft space from 80% RH down to 70% RH while it took each SPT unit 20 minutes to accomplish the same feat.

These test results are in harmony with the manufacturer specified moisture removal rates for all four dehumidifiers. Both the SD-350 and the SD-350TI are rated by their manufacturer to be able to remove up to 11.83 ounces of moisture per 24 hour period at 86° F and 80% RH. The Ivation IVADM35 is rated to remove up to 20.3 ounces while the IVADM45 is rated to remove up to 25 ounces of moisture for the same period of time and at the same conditions (the same temperature and humidity). Thus, both Ivation units have a manufacturer specified moisture removal rate that is also approximately twice that of both SPT units.

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

Power Draw

Both the SD-350 and SD-350TI draw 60 watts of power, the equivalent power draw of a 60W light bulb. The power draw for thermo-electric dehumidifiers, in general, is negligible at best and these SPT units are no exception. Even if you leave any one of these dehumidifiers on non-stop for a full month, you’ll hardly notice a difference in your monthly power bill. Most US residents pay approximately 10 to 15 cents per kilowatt of power used. 60 watts = 0.06 kilowatts. Multiplying 0.06 by 15 cents, you’re paying less than 1 cent per hour to run either one of these SPT dehumidifiers.

Durability (Build Quality)

General Impressions

Both SPT units are, for the most part, built exactly the same way as every other thermo-electric dehumidifier on the market. A plastic shell covers the dehumidifier “core” that does the actual dehumidification. If you’re interested in learning more about the parts that comprise this “core” and how these parts work together to facilitate dehumidification see our thermo-electric dehumidifier buyer’s guide here.

Extra Features

The one difference between the SD-350TI and the SD-350 (and every other thermo-electric dehumidifier we tested for that matter) is the fact that the TI model comes equipped with a titanium dioxide mesh grille and a UV light while the non-TI model does not. The TiO₂ mesh and UV light are supposed to “kill germs and bacteria” although we were unable to test this claim for ourselves. An interesting note is that both the mesh and the light treat air that is exhausting out of the dehumidifier after dehumidification (vs air filters on compressor based units that treat air as it enters the dehumidifier before dehumidification). Note also that the SD-350TI’s manual clearly states that both parts are only effective for up to 1.5 years, after which time you will have to order replacement parts from the manufacturer website.

Ease of Use

Setup Difficulty

Both SPT units are very easy to use. Both units come with a DC adapter that’s plugged into the dehumidifier and a wall outlet. After plugging in the dehumidifier, simply hit the on/off switch to turn the dehumidifier on. A power indicator light will illuminate to confirm that the unit is on and operational. On the TI model a second “UV light” will illuminate in addition to the power indicator light. The dehumidifier will continue to run and dehumidify until its water tank is full, at which time a float switch will auto shut off the dehumidifier and a red “full” indicator light will illuminate. The manufacturer suggests that you first turn off the unit and then remove the water tank to empty it. After replacing the tank and turning the dehumidifier back on it will automatically resume normal operation.

Manual Quality

No manual was included with either SPT unit we purchased for review so we had to look up the manual for each online – both happen to have exactly the same manual that covers both models so only one search was required. The manual itself is fairly straightforward and easy to read although it suffers from the same low resolution grayscale images used in other manuals for other thermo-electric dehumidifiers we’ve reviewed. We understand that this is a fairly inexpensive appliance but for a professional well illustrated manual to be included with purchase, we feel, isn’t compeletely unreasonable to ask for.

Water Tank Size

Both SPT units have exactly the same size 2 liter, or 67.7 ounce water tank. Recall that both units only remove up to about 12 ounces of moisture per day. Thus, you’ll only need to remove and replace each unit’s water tank once every week or so.

The SD-350 and SD-350TI’s water tank size to moisture removal capacity ratio is one of, if not the largest among all of the thermo-electric dehumidifiers on the market. The mini thermo-electric dehumidifiers we tested have much smaller 16 ounce water tanks but don’t remove much less moisture per day than the SPT units (mini units remove approx. 8 ounces per day). Thus, those units need their water tanks emptied and replaced once every 2 or so days. Both the Ivation IVADM35 and IVADM45, like the SD-350 and SD-350TI, have a 68 ounce tank but both units remove much more moisture per day – between 20 and 25 ounces. Thus, those units need their water tanks emptied and replaced once every 2 to 3 days. In summary, most other thermo-electric dehumidifiers on the market require that you empty and replace their water tanks once every 2 to 3 days, depending on how humid and warm the space you’re trying to dehumidify is. The SD-350 and SD-350TI, on the other hand, require that you empty and replace their water tanks once every 6 to 8 days.

This results in both SPT units falling into an interesting niche. They have only slightly more moisture removal capacity than “mini” thermo-electric units and the same size water tank as “large” thermo-electric units, making them the ultimate “set and forget” dehumidifiers. Yes, they won’t dehumidify nearly as fast as the IVADM35 or IVADM45 but you won’t need to worry about emptying and replacing their water tanks nearly as often. If you’re looking to buy a mini thermo-electric dehumidifier (such as the IVADM10, EDV-1100, or DHMD-210) but don’t want to worry about emptying its water tank as often, you can spend the extra $10 (approx.) and pick up an SD-350 instead.

Portability

Compressor based dehumidifiers are comprised of heavy parts because compressor based technology requires these heavy parts for dehumidification to be possible. Conversely, the components required for Peltier technology to operate efficiently aren’t very heavy at all. Compressor based dehumidifiers weigh between 30 and 50 pounds depending on capacity (larger capacity units are heavier). All of the thermo-electric dehumidifiers we tested weigh under 6 pounds.

Thus, thermo-electric dehumidifiers, in general, are highly portable, mostly because they’re very light, and the SD-350 and SD-350TI are no exception to this rule. Both SPT units weigh only 3.65 pounds each. If you’re looking for a dehumidifier you can easily lift to put up in a cupboard or up on a shelf, any thermo-electric dehumidifier is a good option, including the SD-350 and the SD-350TI.

Warranty (Manufacturer’s)

Both the SD-350 and SD-350TI come with a 1 year limited manufacturer’s warranty. We feel that it’s important to note here that unlike other popular thermo-electric dehumidifier manufacturers such as Ivation and Gurin, which only manufacture small inexpensive appliances such as thermo-electric dehumidifiers, SPT also manufacturers much more expensive compressor and desiccant based dehumidifiers which also come with included warranties. Why is this of note? Since consumers are much more likely to contact a manufacturer over a $200 to $300 appliance’s warranty than a $50 (approx.) appliance’s warranty, and since SPT actually sells these more expensive appliances, we feel as if SPT has much more experience in honoring warranties than those other aforementioned thermo-electric dehumidifier manufacturers. If you’re the type of person that fills out warranty cards and will actually contact a manufacturer to have a warranty honored then either one of these SPT units are recommended over any dehumidifier from Ivation, Gurin, and even Eva-Dry.

Value

The SD-350TI retails for about $60 while the SD-350 retails for about $10 cheaper at around $50 (at the time of the writing of this review). Similarly priced units include the slightly less heavy duty “mini” thermo-electric dehumidifiers we’ve tested and reviewed. These are the Ivation IVADM10 and Gurin DHMD-210 which retail for about $40 each, and the Eva-Dry EDV-1100 which retails for about $60. More heavy duty options are more expensive. The Ivation IVADM35 and IVADM45 retail for between about $90 and about $100 each.

Final Thoughts

Even though the SD-350 and SD-350TI are very similar products we have to address them separately in making our recommendations. Let’s talk about the SD-350 first, and then we’ll finish our review with the SD-350TI.

The SD-350 is 25% more expensive than the IVADM10 or DHMD-210 but it removes 50% more moisture per day. This makes the SD-350 a better value than both the Ivation and the Gurin in terms of moisture removal rate. So, if moisture removal rate and value is your primary concern, the SD-350 is the better option. The Ivation and the Gurin are, however, much quieter. If you’re going to be using the dehumidifier in an environment that needs to be as quiet as possible (such as a bedroom) then we would definitely recommend the IVADM10 and especially the DHMD-210 over the SD-350.

The Ivation IVADM35 is 180% more expensive than the SD-350 and the Ivation IVADM45 is 200% more expensive than the SD-350. Both units are less than (only slightly but still less than) 200% faster than the SD-350 at removing moisture. Thus, once again, the SD-350 is the better option if moisture removal rate vs value is most important to you. Both Ivation units are, however, much quieter than the SD-350. If you’re looking for a unit that can remove more than twice the moisture of a mini thermo-electric dehumidifier (remember, this category includes the IVADM10, DHMD-210, etc.) albeit at twice the price, but that is still quiet, either Ivation unit (either the IVADM35 or IVADM45) is the better option. The SD-350 is not recommended for anyone that is looking for a quiet dehumidifier.

The extra $10 (approx.) you pay for the SD-350TI skews our recommendations just enough to make them exactly opposite of what we’ve outlined above. We do not recommend the SD-350TI over the Ivation IVADM10 or Gurin DHDMD-210 under any circumstance. It doesn’t have a better cost to moisture removal rate ratio and it’s also much louder. We also do not recommend the SD-350TI over the Ivation IVADM35 or IVADM45. Once again, because of its higher price it doesn’t have a better cost to moisture removal rate ratio than either Ivation unit and it’s also much louder than both Ivation units.
In summary, in terms of how much you pay for the moisture removal rate you get, the SD-350 is a very good option at least among those thermo-electric dehumidifiers we’ve actually tested. Both the SD-350 and SD-350TI are, however, not recommended if you’re looking for a quiet dehumidifier.As far as energy efficiency, reliability, and portability are concerned it’s essentially a tie between all thermo-electric dehumidifiers on the market. Only buy the SD-350TI if you want to see if the UV light and mesh grille makes a difference in the air quality of the space you’re dehumidifying (and you need it to). There is no other reason to buy it. Do keep in mind, however, that you will have to replace those parts once every 1 and a half years.