The Bottom Line
The Tenergy Otis offers surprising performance, considering the price. This is one of the least expensive robots we’ve tested, but its cleaning performance was closer to robots almost twice its price. Also includes a simple, but good enough feature set, including remote control, scheduling, and varied cleaning modes. All in all, an excellent value robot vacuum.
- Strong cleaning performance on all indoor surfaces.
- Amazingly low price, considering the overall performance level.
- Has a tendency to fling debris around when trying to clean it up.
- This Tenergy struggles to get into corners, even with two brushes on the bottom of the unit.
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The Tenergy Otis offers a design similar to others we have seen before, such as the Ecovacs Deebot N79 and Eufy RoboVac 11. The overall look is simple, but their are still a number of noteworthy features present.
More on design:
Much like most robot vacuums, the Otis is built in a circular shape. The top of the unit is all based on touch, there are no physical buttons. Once the vacuum is turned on, via the switch on the side of the Otis, information about the vacuum will appear on the top interface in a blue color.
The bottom of the Tenergy Otis contains three wheels, two spinning brushes, and a multi-surface brushroll. In addition to these items, a power switch is housed along the side of the Otis, as well as a pin charger.
How about the aesthetics?
Overall, this Tenergy robot vacuum offers a clean look. The touchscreen is a nice add, and not something we’ve seen in many other robots we’ve tested.
How Tenergy Otis Cleans
The Tenergy Otis cleans in standard robot vacuum fashion. That said, this unit does offer a few different cleaning modes.
- Auto cleaning
- Edge cleaning
- Spot cleaning
- Double cleaning
While users have all four of these options available, they can also turn on the turbo cleaning mode, combining it with each of the four modes, for a total of eight cleaning modes.
One of the best perks about the Otis is its ability to set scheduled cleanings.
Users can create a cleaning schedule, at which the Tenergy will automatically begin cleaning, on the scheduled time. Once finished, it will return back to its charging dock to refuel before its next scheduled cleaning.
Therefore, you may never have to turn the Otis on if you don’t want to. Just set it to a schedule that works for you and the vacuum will do all of the grunt work for you.
As a whole, the Tenergy Otis is going to sweep, agitate, lift, and suck up dirt and debris as it passes over.
Each cleaning mode will work in this particular manner, yet while doing so it will focus on more specialized pathing. For example, edge mode literally means the robot vacuum will follow along with the edges of walls and baseboards in your home while cleaning.
Are there any sensors on this robot vacuum?
The Otis does include wall and edge-drop sensors. The wall sensors help this vacuum avoid running into the wall. Throughout our cleaning tests, we were able to see the Otis avoid bumping into the walls.
The edge-drop sensors help prevent the Tenergy Otis from driving off of edges (i.e. stairs).
I’m sure you’re curious about the surface transition…
With some large wheels, the Otis is able to transition from hard floor surfaces to carpets and rugs with ease. Some other robot vacuums we have tested (most notably the Pure Clean robot) have not been able to make these transitions, simply due to their smaller wheels.
Tenergy Size & Dimensions
The Tenergy Otis is average with regard to size and dimensions. This robot vacuum is 13.25″ wide and 3.75″ tall. Additionally, this vacuum weighs 6.6 lbs.
- Length – 13.25
- Height – 3.75″
- Weight – 6.6 lbs
This robot vacuum includes a good number of extra parts and accessories.
As a robot vacuum, not much is needed in order for this unit to function, but Tenergy Otis included a few extra pieces so users would have backups for maintenance and overall performance.
The included parts and accessories are as follows:
Remote control: A small remote control is included with this robot vacuum. Users have the option to use the remote instead of getting up to turn on the Otis manually.
Charger: One charging dock and a pin connector is also included with this Tenergy robot vacuum. You can plug the pin charger into the robot directly, or into the charging base, whichever you prefer.
Side brushes: Six side brushes are included. Two will be placed on the unit immediately, but this does give users four extras as replacements.
Cleaning tool: A cleaning tool is included to help remove tangles in the brushroll as well as dirt / debris from the filters.
HEPA filters: Two HEPA filters are included, one of which will already be inside of the robot vacuum and one is used as a replacement.
Tenergy does a nice job of including a good number of parts and accessories, most of which can be swapped out as needed. Users will not have to worry about purchasing any backup pieces initially.
The following vacuum cleaner tests are designed to show how the Tenergy Otis vacuum performs on different surfaces, picking up a variety of debris types.
We test on three different floor types, including:
- Hardwood floors
- Low pile carpet
- High pile carpet
- Hardwood floor 96% 96%
- Low pile carpet 99% 99%
- High pile carpet 86% 86%
For each floor type we test the vacuum cleaner against:
- Rice – 3 ounces
- Dry Cereal – 1 ounce
- Kitty Litter – 3 ounces
- Sugar – 3 ounces
Each of the aforementioned debris types was spread across our testing lane. The base surface of our testing lane is an engineered hardwood floor. For our carpet tests, we slide in a low pile and high pile carpet insert on top of the hardwood floor.
Our vacuum cleaning process strives to be as consistent, fair, and true to real world use as possible. Our tests utilize the following procedure:
- Measure the weight of the testing debris and the weight of the empty vacuum debris container.
- Spread the respective debris type evenly across the central portion of the testing lane.
- Run the vacuum cleaner over the testing lane.
- Measure the weight of the now filled container and take notes on the cleaning performance.
See our series on robot vacuum reviews here.
Hardwood Floor Cleaning
The hardwood floor cleaning tests were a success for the Tenergy Otis. All four debris types were cleaned at least 91% of the way.
There was a small struggle:
While the Otis did a fine job of cleaning up all four of the debris types, the spinning brushes have a tendency to fling each of these debris types around our testing lane. Typically, this lead to the debris piling up in corners, which the vacuum was not able to get.
Therefore, the numbers were good, but I did not like that there were visible amounts of each debris left in all four corners of our testing lane after the tests.
- Hardwood Floor – Rice 95% 95%
- Hardwood Floor – Cereal 99% 99%
- Hardwood Floor – Kitty Litter 91% 91%
- Hardwood Floor – Sugar 99% 99%
Low Pile Carpet Cleaning
As we moved to a low pile carpet, the Otis performed much better. The friction between the carpet and the debris did not allow the vacuum to sweep the debris into the corners, as much.
All four debris were dominated. The lowest score we saw was a 97% (on kitty litter).
The other three debris reached 99% and higher. This was an impressive performance by the Otis on low pile carpets.
- Low Pile – Rice 99% 99%
- Low Pile – Cereal 100% 100%
- Low Pile – Kitty Litter 97% 97%
- Low Pile – Sugar 99% 99%
High Pile Carpet Cleaning
Unfortunately, we did not see the same results on our high pile carpet tests.
Rice, cereal, and kitty litter were easy messes for the Otis to handle. Each of those three scored 96% or higher.
The problem was sugar.
With the sugar falling into the thicker pile of the carpet, the standard cleaning mode of the Otis was not able to suck up more than 51% of the sugar. Meaning, 49% of the sugar remained within the carpet.
From there, we decided to run the test with this Tenergy on turbo cleaning mode, with the remaining sugar. After doing so, the vacuum was able to grab 33% of the sugar, which brought us to a final total 84% debris removed.
- High Pile – Rice 100% 100%
- High Pile – Cereal 98% 98%
- High Pile – Kitty Litter 96% 96%
- High Pile – Sugar 51% 51%
The Tenergy Otis is extremely easy to use. Between the touchscreen interface and the remote, all features associated with this robot vacuum are easy to understand.
Initial setup requirements:
Right out of the box, there are only a few steps to get this vacuum set up.
- Remove plastic wrap from individual parts
- Pop in two spinning brushes
- Charge the vacuum
After these three steps have been taken, you’re ready to rock and roll.
How easy is it to empty the dustbin?
The dust bin is located under the main flap on top of the Otis. Lift this up, grab the handle on top of the dustbin, remove it and empty the contents inside of it into the trash.
My main complaint about the dustbin its tendency to spill when being emptied. As you go to open the dustbin, there is a small hole which is the opening for dirt and debris to enter the dustbin during cleaning. If you do not hold the bin at the correct angle, the debris inside will spill out before you empty it into the trash.
After releasing it, emptying the debris from the inside of the dustbin was a bit trickier. Although there was a sticker on the unit demonstrating how to open the bin, it was still not clear, from my perspective.
After fooling around for a few minutes, I was able to open the dustbin via the small latch on the side of the unit.
Using the remote:
While this Tenergy robot vacuum does not have wifi connectivity, it does have a remote. The remote gives users the option of controlling the Otis from elsewhere in your home.
The remote clearly displays all of the cleaning modes offered by the Tenergy Otis, which is a major bonus. Some remotes included with robot vacuums are hard to understand, making the remote more of an inconvenience than anything.
If you like the idea of not having to get up to manually turn on the robot vacuum, Otis’s remote can be a major pro.
The Otis maneuvers well, as its size allows it to do so. Similar to most robot vacuums, the Otis is small in height and is able to get underneath furniture without getting stuck.
The ability of this robot vacuum to move under and around furniture with ease is a great characteristic of the Otis.
Once again, the Otis has four cleaning modes, as well as a turbo mode that can be added to each of the other modes. With these options, users can clean in a more specific manner, if need be.
Does the vacuum remember your home’s layout?
The Tenergy Otis does not have mapping technology. Therefore, it is not able to remember your home’s exact layout. That said, the wall and edge sensors to help it navigate around your home quickly and efficiently.
The following table indicates the frequency at which you will likely want to replace the various parts and components of the vacuum.
However, your individual experiences may vary
|Accessory / Part||Replacement Frequency||Replacement Cost|
|HEPA Filter||6 months||Not available yet|
|Brushroll||As needed||Not available yet|
|Battery||1-2 years||Not available yet|
Maintenance on the Tenergy Otis is straightforward.
- Replace the filter – In order to keep the Otis running at peak performance, you will need to change the filter. Tenergy recommends doing this every 3-4 months, but this will vary depending on how often you use the vacuum.
- De-tangle brushroll – Freeing the brushroll of any tangles will also make a huge difference in the vacuum’s cleaning performance.
Annual maintenance costs for the Tenergy Otis are unclear, as we could not find a place to purchase replacement parts.
However, this is usually common practice for new robot vacuums. We would expect them to be available within the coming months.
How Loud is the Tenergy Otis?
All vacuum cleaner reviews on Modern Castle are put through our standard noise test. For this test, we use a sound meter to measure noise in terms of decibel level approximately 3′ away from the vacuum.
The Tenergy Otis sits at 64db on the noise scale.
How long can the Otis vacuum run?
All cordless vacuum reviews on Modern Castle are put through a standard assessment of battery size, runtime, life, and replacement cost.
|Charging Time||4-5 hours|
|Run Time||90 minutes|
The Tenergy Otis offers a great value. The strong cleaning performance and low price combine for a strong value overall.
How good is the cleaning performance?
During our cleaning tests we saw a strong outing from the Otis. The robot vacuum was able to clean up almost all debris types, on all three of our floor types.
There were some struggles with flinging debris and digging deeply into the high pile carpet. Aside from these issues, the Otis performed quite well.
Maneuverability was another positive characteristic of the Tenergy Otis. This robot vacuum was able to move quickly and efficiently around my home.
Don’t forget about maintenance…
Maintenance costs are the one area I’m a bit worried about. Since the replacement parts aren’t currently available we cannot determine an estimated annual cost.
With regard to warranty and returns, Tenergy offers a 1-year warranty and a 30-day return policy (via Amazon).
Below is a complete list of important specifications and features included on the Tenergy Otis robot vacuum:
|Floor Type||All (indoor)|
|Dust Bin Capacity||0.9 L|
|Returns||Varies by retailer|
The Tenergy Otis is a well-valued robot vacuum. The strong cleaning performance and inexpensive cost make this robot vacuum a great choice for a wide variety of users.
I would recommend the Tenergy Otis if you’re looking for the following features in a vacuum:
- Want a strong performer – The Tenergy Otis performed well throughout our cleaning tests. With the ability to place this robot vacuum in turbo cleaning mode, in addition to the four other cleaning modes, users have a few different options when it comes to vacuuming their home.
- Want a long run time – The Otis has the ability to run for up to 90 minutes. This is an excellent run time, considering price and performance.
- Want to save some money– If you want an advanced robot vacuum, but don’t want to spend a fortune, the Tenergy Otis could be a solid option. This robot vacuum is priced well below the vast majority of others in the industry.
Low Cost, Impressive Performance
The Tenergy Otis is a robot vacuum with a good amount of features, an impressive cleaning performance, and a low price. This is one of the less expensive robot vacuums we have seen to date. The overall value, based on performance and price, is quite good. There is not much else I would ask for from a robot vacuum priced in the $ tier.
Why did the Tenergy Otis score the way it did?
- Design – The design of the Otis is nice. Simple interface and strong build overall.
- Performance – All in all, the performance was strong. There were a few issues with flinging debris around and getting into corners, but otherwise, this vacuum cleans well.
- Quality – Looks and feels nice. Not the same as some higher end robot vacuums, but certainly well-made for the money.
- Usability – Multiple cleaning modes and a remote make this vacuum a versatile unit in terms of usability.
- Value – Inexpensive, strong performer, easy-to-use, and a few bells and whistles. Good value overall.
Derek Hales is the Editor-in-Chief and Founder of ModernCastle.com. He is a passionate perfectionist when it comes to testing and reviewing products for the home. When he is not testing new products, Derek enjoys golf, tennis, and PC gaming. Derek lives in Phoenix, Arizona, with his wife, Samantha, son, and poodle, Tibbers.