I got the Litter-Robot 3 Open-Air years ago and later on, I upgraded it to a Connect version by installing the Connect WiFi kit so I could operate it with the Whisker App. This device is the best invention ever made to manage the cat’s waste. Now I have the Litter-Robot 4, which my cat has been using so I decided to make a comparison between both Robots. For this purpose, I created a side-by-side comparison table where you can see differences at a glance. Also, I further explain the differences in functionality and benefits. I will be updating this comparison as more features and pros & cons come up.
Weight (without cat litter)
Dust-reducing sifting screen
How activates the unit
Types of sensors
WhisperQuiet™ Cleaning cycle
Full drawer Indicator
Cat litter Indicator
Real-time tracking litter & drawer levels
Control panel location
Cat weight detection
Option without Wi-Fi
22” W x 27" D x 29.5" H *
22” W x 27” D
15.75” W x 15.75” H
Wide round flat faced
3, 5, 7, 15, and 30 minutes
Motion sensor at the entry
Motion sensor at the entry + on step + inside Globe
Curtain sensor & SmartScale™ sensor
Suitable for up to 4 cats
Adult cats and kittens weighing 3+ lbs
Handle and Step
On top of the Globe
Outer bottom of Globe
Custome schedule | Weekdays/Weekends
Auto, ON or OFF | High, Medium or Low
24.5” W x 27" D x 29.5" H
24.5” W x 27” D
10.25” W x 15.5” H
3, 7, and 15 minutes
Weight sensor on step + inside Globe
Weight sensor on step + inside Globe
Ideally up to 3 cats
Adult cats and kittens weighing 5+ lbs
At the bottom, on the right side
On waste drawer's vents
8 hours from start time
Auto / OFF
*Dimension considered for Litter-Robot 4 with step. There is another version with a handle (no step) with a 23” depth. **Open Air has been discontinued.
Differences In Core Features
These are the upgrades that are related to the operation of the litter box, which is self-cleaning, and also to the structure of the unit.
A special QuietSift™ patented technology allows the new Litter-Robot 4 to be a much quieter unit during a cleaning cycle. You can easily put this device next to a bedroom and you won’t notice a cleaning cycle.
Upgraded Sifting screen
The new sifting screen of the LR4 has been designed in a way that produces fewer particles in the air when it’s sifting the cat litter. This creates less dust on the surface of the rubber bottom as well. This is good for people or cats with a tendency for allergies.
Cycle Activation: Now with Two Sensors
The Litter-Robot 4 features two sensors; a Curtain Type Sensor, consisting of 3 motion “eyes” located at the entry of the Globe. This sensor detects the cat entering the litter box and activates the unit for a cleaning cycle. The other sensor is a Smart Weight-Scale Type Sensor at the bottom of the unit, called SmartScale™ technology. This Smart sensor registers the presence of a cat inside, records the weight of the cat, and also activates the Litter-Robot 4 when weight is sensed inside. We could say that both types of sensors complement each other and ensure the activation of the device, safely. The Litter-Robot 3 on the other hand, features a weight scale sensor at the bottom of the Globe that only activates when a cat steps on the step or when the feline is inside the unit. Regarding the sensors with both Litter Robots 3 and 4, you must reset the unit every time you add new cat litter or when you empty the waste drawer to refine the accuracy of the cat’s detection.
The location of the nightlight in the Litter-Robot 4 is safer and more effective because it’s located at the entry, with the lights pointing directly to the litter bed. With the Litter-Robot 3 Connect, the night light was located on the underside of the Bonnet. Since the Bonnet needs to be removed periodically to clean the Globe, this small electronic piece could get damaged if not careful.
The new Litter-Robot 4 is not only more compact with a neater look but also uses less space on the floor since it features a smaller footprint.
Also, the new LR4 offers two models: the LR4 with step and the LR4 with handle. The model with the handle is for cats that jump into the unit and don’t use the step. The model with a handle uses less space because it has a shorter depth so it’s a good option for people who have less space to accommodate the device.
Differences App Features
The addition of smart sensors to the Litter-Robot 4, such as the curtain sensor and the smart weight sensor, is reflected in new features of the Whisker App in comparison with the Litter-Robot 3 Connect.
Comparison of Whisker App Features Between LR4 and LR3
Real-time Tracking of waste drawer
The Litter-Robot 4 allows you to know in real-time how full is the waste drawer. The special motion sensor located at the entry emits 3 cone-shaped lights toward the litter bed. When the globe is rotating and the opening where the waste drops through is positioned at the bottom, these sensors detect the waste dropping and down into the waste drawer to determine the cat waste. Additionally, a smart weight sensor (SmartScale™ technology) located at the base of the unit registers the weight of the waste drawer as it increases its level. Both sensors work together for a more accurate waste level that, through the Omnisense™ detection technology, sends the information to the Whisker App. The waste drawer indicator can be seen at a glance on the App’s homepage (see figure).
The Litter-Robot 3 Connect, even though it shows the waste level indicator on the App home, is not in real-time; you need to reset the “Gauge” on your App every time you empty the drawer. The waste level indicator of the “gauge” is calculated based on the number of rotations, unlike the Robot 4 whose weight sensor and the Omnisense™ technology send the information to the App right after you empty the litter box and press the reset button of the unit.
Real-time tracking of litter level
The smart sensors of the Litter-Robot 4, together with the Omnisense™ technology, allow this unique feature of showing on your App how much cat litter the Robot has. It will indicate, Optimal or Low in a bar you can see at a glance in the App’s status. When the cat litter level is optimal, the bar shows blue, and when the level is low, the bar is red. I must mention that after adding cat litter, a new litter level is reflected after a cleaning cycle.
Cat weight recording
This is a unique feature of the Litter-Robot 4. The Smart scale sensor that is located at the bottom of the unit weighs and records the last weight detected inside the Globe and sends this information to the App. This is excellent for determining which cat used the litter box the last. This weight recording is reflected on the Litter Robot’s activity list which you can see on the Status menu. The Litter-Robot 3 Connect doesn’t feature the cat’s weight recording.
Is there any weight limit with the Litter Robot 4?
There is no weight limit for any of the Litter Robot devices and that includes the Litter Robot 4. If a cat fits inside the Litter Robot and can maneuver, it doesn’t matter how much the cat weighs, the Litter Robot will work.
The Litter-Robot 4 and Litter-Robot 3 Connect both feature nightlights to orientate cats at night. The difference is the location of the light in the globe as we mentioned previously, and also the flexibility that the LR4 offers on the Whisker App which the Connect doesn’t. The Litter-Robot 4 allows you to turn the nightlight ON (at all times), OFF (not nightlight at all), or in AUTO mode, which means the nightlight turns on automatically when it gets dark. Also, the light settings can be set to Low, Medium, or High. With the Litter-Robot 3 Connect you can only change the nightlight to OFF or AUTO mode, and you can’t set the light intensity.
Sleep Mode customization
The Litter-Robot 4 allows you to set the unit on standby for as many hours as you need. For example, if you need the litter box to stop operating from 10 pm to 8 am you can do that. Also, you can set the sleep mode on weekdays or weekends, or both. The settings for weekdays can be different from weekends as well. On the other hand, the Litter-Robot 3 Connect only allows you to set the sleep mode for 8 hours from the time you set the start. And this will repeat every day, from Monday to Monday.
My Video Comparison Between Litter-Robot 4 vs Litter-Robot 3
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Odor Management Differences
The Litter-Robot 4 added some improvements for better odor control.
The Litter-Robot 4 features a filter compartment at the outer bottom of the Globe. In this compartment, you place the carbon filter that will be sitting right above the waste drawer. This location is strategic because it traps the odors from the waste drawer as it rises. The Litter-Robot 3 Connect, instead, features the carbon filter in front of the waste drawer where the vents are. This helps reduce odors, but odor gases rise and you may smell it when you open the waste drawer.
The OdorTrap Pack is a Whisker product created for Litter Robots in order to manage odors more effectively. With the new Litter-Robot 4, you can place the OdorTrap bag inside the compartment located on the outer bottom of the Globe without the need to purchase the holder (OdorPack Pod). With the Litter-Robot 3 in order to use the OdorTrap, you have to purchase the OdorPack Pod so you can place the bag inside the holder which is attached to the inner wall of the waste drawer by integrated magnets.
The Waste Drawer of the Litter-Robot 4 is tightly sealed, containing odors much better. Also, the waste drawer is deeper, the edges don’t have clips and nooks to tuck the bag in, and instead, the edges are flat allowing you to simply wrap the bag on top. The Litter-Robot 3 waste drawer edges are not smooth and for this reason, the drawer sealing when shut is less in comparison to the Litter-Robot 4, although the litter clumps and odors are still pretty well contained.
Multi-cat Design & Safety Differences
Differences that may tip the balance towards the Litter-Robot 4 if you have multiple cats.
The Litter-Robot 4 features the SafeCat™ system which consists of 3 motion sensors at the entry of the Globe. This patented technology called Omnisense™ allows the activation of the unit by the detection of the cat’s body crossing the entry. This curtain-type sensor also ensures the cat’s safety in case the Globe is rotating and a cat enters the unit because it stops completely the operation if it senses the cat. The Litter-Robot 3 features a weight sensor on the step and at the bottom of the unit so the rotation stops if a cat steps on the step or if it jumps into the Globe by detecting the cat’s weight inside.
The Litter-Robot 4 features a smart scale-type sensor that records the cat’s weight right after every use. This way you can recognize which cat used the litter box the last by their weight.
The new Litter-Robot 4 features a wider entry and roomier space inside the Globe for cats of any size. Large cats can enter the unit much easier. The LR3 Connect features a narrower entry with an oval shape.
The delay time is the time between the Litter-Robot getting activated and the actual cleaning cycle. With the Litter-Robot 3 Connect the settings are 3, 7, and 15 minutes. With the Litter-Robot 4, you can decide if the cycle delay is 3, 5, 7, 15, or 30 minutes. The 30-minute wait time is good for multi-cat use, this way two cats could use the litter box before a cleaning cycle.
I have been using the Litter-Robot 3 for years and I can attest that it’s the best invention created for cat owners. Now I have been using the Litter-Robot 4 for almost nine months and I can see improvements regarding the Connect, but both units accomplish greatly the main function which is self-cleaning the litter box efficiently. Personally, the main difference in features: the sensors, litter level indicator, and noise level, are great improvements. However, in my case, they are not essential and I could live without them because my Robot is in the laundry room away from the living areas, and I empty the waste drawer every Sunday together with pouring more cat litter inside the Globe. But I am sure so many cat owners appreciate the higher safety level of the new Litter-Robot 4, the lower noise level, the litter indicator, the cat weight recording, the smaller footprint, the roomier interior, and so much more.
Both, the Litter-Robot 4 and the Litter-Robot 3 are excellent devices! I suggest getting the Litter-Robot 4 if you are a multiple cat owner who needs a quieter device when operating, and if you need a reminder to refill the globe with cat litter. Also, the new Litter-Robot 4 is suitable for cat owners who want to manage more options and flexibility with some features on the Whisker App.
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