iRobot Looj 330 gutter cleaner review

Clogged rain gutters are probably not a known problems for those who live in an apartment building or in a family house without deciduous trees. But there are houses where this is a returning problem every single year, and this is not as rare as some might think. iRobot’s Looj 330 seems to be the perfect tool to aid this tiresome and sometimes dangerous task.

In practice

It might be obvious after the last page that the preparation of the robot does not require a masters degree from MIT. Only the selection of the right ejector needs some sort of experimenting. Too bad that the swapping of the ejectors require a phillips screw driver, other than this, the process is extremely easy. However it’s a nice design touch that the ejectors cannot be installed in a wrong way because they don’t fit in if not inserted with the proper direction.

For our first test we have selected a short, 4 m (13 ft) gutter section that was accessible from the ground with short ladder. The gutter was full of acacia leaves and twigs, but they were mostly dry and did not form a solid block. Although this short section of gutter could have been cleaned by hand conveniently from the ladder, the easy access made it a perfect spot to experiment with the robot.

To be able to place the Looj 330 into the gutter I had to push the leaves and the twigs aside on a 50 cm part. It would have been logical to remove the leaves from that spot, but I just pushed them over to one side to build a larger hill of debris for the Looj to clean.

The Looj fits very comfortably in the rounded half pipe shaped gutter installed on my house. It’s safe to say that even the previous generations would have worked as well with these gutters. To allow the robot the chance to clean the whole gutter from side to side I first installed the 8 cm long ejectors, but I soon realized that my initial fear become reality. The Looj was spinning around its auger’s axis several times in every minute, what turned the forward motion into a backward movement immediately. This slowed the robot considerably because the Looj has no sensor to realize if it runs upside-down. Eventually it would have gone all the way through, but it wasn’t a good thing to watch.

The Looj 330 goes forward slowly for about 2 seconds, then reverses quickly for a half a second. This back and forth movement helps the auger to break up the solid blocks of debris in the gutter. There is no pressure sensor in the nose of the robot to detect if it reached a solid obstacle, but this repeated procedure keeps the Looj moving even in tough gutters.

After about 2 meters I decided to switch to the shorter ejectors. The behavior of the robot changed dramatically. The Looj 330 did not spin at all with shorter ejectors, just kept going until it reached the end of the gutter. Of course the shorter ejectors did not reach all the way to the sides of the gutter, so a small amount of leaves have remained in the gutter, but the majority was lifted out nicely. The brushes behind the ejectors had swept some of the remaining debris out of the gutter. The result is not perfect, but very close. The rest of the small leaf parts will be washed down by the first rain, so the gutters will be nice and empty.

After this warm-up run I called some help because I was scared to climb any higher. The rest of the gutters were only reachable from the rooftop, so I needed someone with a proper experience and a safety harness. According to the expert, these are the places where the Looj can be a huge help. When the roof is steep, and the gutter is not reachable from a ladder, they have to descend from the roof on ropes at every two to three meters what is extremely time consuming. The Looj can be started from one point at each straight sections and will do the job quickly.

Unlike in the test gutter, the leaves and twigs had formed a solid plug in this approximately 10 meters long gutter section. The gutter cleaning specialist did not expect the Looj to be able to handle that, but he was wrong. The Looj 330 had gone all the way to the end, and with a little help from the expert it cleaned the gutter nicely. The help was only needed because the tiles on our roof reach too deeply into the gutter and when the Looj was returning to the starting point and climbed on top of the remaining leaves, it hit the tiles and got stuck. We have decided to turn the robot around in 180 degrees, so the auger and the ejectors could get rid of the remaining leaves before the Looj treads could climb on top of them.

No robot is perfect, as this one has room for improvement as well. Although it does a good enough job, 2-3 times wider brushes behind the ejectors would sweep out a lot more debris and dust from the gutter (or reach the same level of cleanness with less runs). My other problem was that the robot does not detect the end of the gutter so the operator has to keep an eye on the Looj. Of course the robot has to be looked after anyways, so it is not a huge problem, but it would be a nice feature from a so called robot. A little more serious issue is that the Looj does not detect when it is upside down. Without that cheap orientation sensor the tread transports the robot to the wrong direction when it is on its back, wasting precious battery power.

Despite of these glitches I have no reason to complain. The Looj delivers perfectly what I expect from such a device, and even the gutter cleaner expert was satisfied.


After cleaning nearly 15 meters (50 ft) of gutter the Looj looked dirty and a bit beaten, but thanks to the watertight sealing, I could simply clean it with the watering hose. The user manual recommends us to remove the treads that can collect a significant amount of debris. Despite of the rubber coated buttons the handle is not waterproof, therefore it must be removed from the robot before cleaning.

To have the waterproof sealing work we have to make sure that the rubber sealing is clean when the battery is inserted. Therefore it is recommended to clean and dry the robot before the battery compartment is opened to avoid dirt and debris fall into the hinge section of the flip-out battery drawer.


According to the user manual the iRobot Looj 330 can clean 60 m (200 ft) of gutter before the battery is depleted, but it doesn’t say how many repeated runs are allowed in each sections. We have run the robot in each gutter at least 3 times back and forth, what adds up to more than the given length, but the battery was still ok. Given the short amount of time I could not test the real capacity of the battery, but it seems to be very decent.

The review is not over yet!

Next page: Conclusion

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