It can be difficult to choose between the iRobot Roomba 770 and the Roomba 780. The model numbers aren’t the only thing close together; the features are too. One thing that isn’t so close is the price. Currently there’s about a $100 difference. Is the extra cash for the 780 worth it?
|Features||Roomba 770||Roomba 780|
|Full Bin Indicator|
|Room Confinement||Virtual Wall||Virtual Lighthouse|
|Virtual Wall Halo||optional||optional|
|Weight||8.4 lbs||8.4 lbs|
|Review||Roomba 770||Roomba 780|
|Where to buy?||Best Price||Best Price|
First, a few words about what the Roomba 770 and 780 have in common.
First, the two models look nearly identical. The 770 is black with a medium grey border; the 780 is dark grey with a pair of light grey borders. They’re very close and, of course, it’s a matter of personal taste, but I prefer the look of the 770. Your milage may vary.
The objective factors are even closer to the same, in fact often identical. The Roomba 770 is a circular disk measuring 13.9″ in diameter and standing a mere 3.6″ high, exactly the same as the 780. They even weigh the same: 8.4 lbs. I haven’t taken one apart (yet) but I’d wager that the innards are exactly the same part numbers.
- Cleaning Mechanism
Each sports the same 3-stage cleaning mechanism that helped make Roomba the standard in robotic vacuum cleaners for so long.
Stage 1 consists of a pair of airplane propeller-shaped horizontally rotating brushes about the size of half a pencil. They help move dust and hair from edges and crevices toward the unit to be picked up by Stage 2.
Stage 2 is a pair of counter-rotating brushes on the base that sweep up that dirt and hair into the circular chamber. Some feel the brushes are too stiff and harsh but I’ve never had any damage to wood floors or delicate carpet from them.
Stage 3 is the vacuum chamber itself, considerably different from the one you would find in, say, a Dyson or other upright bagless vacuum cleaner (or even a canister). And, it’s powered by a 30W motor that runs off a rechargeable battery.
That whole assembly, part of what is sometimes called the CHM (Cleaning Head Module), may be slightly better in the 780 than the 770 but it would require sophisticated test equipment to tell the difference. The difference is slight at best, not worth $100 by itself.
- Dual HEPA Air Filters
The 770 has improved HEPA filters over prior models and the ones in the 780 are the same. Without going into technical details, they simply filter more and last longer. iRobot recommends replacing them every three months – a period that will naturally vary depending on how often you vacuum and what your environment is like – but that’s probably overkill.
Even so, they’re not expensive compared to the ones found in a good air purifier unit. On the other hand, they’re not the same quality, either, nor are they intended to be. On the other hand they have to deal with much more and much heavier dirt than those in an air purifier. They cost (currently) about $20 for a pair of 3-packs; you replace them in the unit two at a time.
- Sensors and Navigation
The 770 and 780 have similar sensors and navigation technology. Each sports the same set of IR (Infrared) and acoustic sensors. The IR sensors work in combination with the acoustic ones to sense dirt and debris in two different ways – not just its presence but the composition and density as well.
They can sense the difference, for example, between very airy dust and much denser sand on the floor. They allow the firmware to make intelligent decisions about whether to go over an area repeatedly or to move on, part of what iRobot calls its Dirt Detect 2 with Persistent Pass Cleaning system.
So, if they are so similar what accounts for (or justifies) the much higher price for the Roomba 780? There are, in fact, a few very interesting features that can make it worth the extra coin over the Roomba 770.
- Virtual Walls vs Virtual Lighthouses
One important difference is found not in the robot itself but what accompanies it in the box, and what assists it in cleaning. The 770 package houses a pair of Virtual Wall units and the 780 Virtual Wall Lighthouses. They operate similarly but have an important difference.
A Virtual Wall unit simply keeps your Roomba from wandering into the next room when you want to keep it confined. Staying longer in the living room, for example, lets it clean more before running out of battery life.
The Virtual Lighthouse, by comparison and contrast, can be a Wall but also can intelligently direct the 780 into another room deliberately. That optimizes battery life and helps you tailor how you want the robot to clean your house. A simple switch in the front of the Lighthouse lets you choose which mode – Wall or Lighthouse – you want for any given session. You can also adjust the sensing distance up to about 15 feet.
Currently, the Lighthouse can only be used with the 780. If you bought it as a separate accessory it wouldn’t work with the 770. I qualify that with “currently” because you never know when the manufacturer or someone else might make a change to a product that makes the Lighthouse useable by the 770. By the time you read this there’s always the possibility that someone will have made them work together. I mention the possibility of “someone else” because iRobot encourages open source software development for their iAdapt system.
- Touch Controls
The other difference between the iRobot 770 and 780 may or may not be considered major, depending on your preference. The 780 offers new capacitive touch-sensitive controls on the top of the robot; the 770 uses physical buttons. Personally, despite being a huge fan of my iPad, I prefer the latter here. Still, that’s largely a matter of taste. There’s no functional difference in how well the Roomba responds to one or the other.
Is the Roomba 780 worth $100 more than the Roomba 770? There’s no way for me to decide that question for you. Personally, I value my $100 more than I value a pair of Lighthouses and a touchpad control panel. The slight difference in coloring I consider a wash from the perspective of value and money. You may reasonably come to the entirely opposite conclusion. In either case, you’ll get a superb robot vacuum cleaner.