Battle of the Affordable Home Vacuum 'Bots

These two robotic vacuums are direct competitors: both are in the same price range and are widely available in the US. How do they compare? It's not an easy decision if you're shopping for a mobile, autonomous dirt-erradicator, and in an ideal word we'd see a unit that combines the best of both!

Price: Roomba Discovery costs $20 less. Update: iRobot raised the Discovery price to $279 in March 2005. Sharper Image is currently discounting the $299 eVac to $149.

Spot Clean: They both have this feature. Roomba covers the area in concentric widening circles until a 3 to 4 foot area is clean. eVac does a criss-cross star/back and forth pattern to cover a 3 foot area directly in front of it similar to the way humans vacuum.

Pet Hair: Both are perfect for pet hair and do a very good job.

Noise: The eVac is noisier and sounds like a moderately powerful traditional vacuum. The Roomba Discovery is quieter, no shouting required to have a conversation while vacuuming. Our cat is terrified of traditional vacs, a bit leary of the eVac and could care less about Roomba.

Cleaning algorithm (how well it covers the floor): The Roomba Discovery wins by a bit. The eVac uses a pattern that's more similar to the way humans vacuum: a back and forth pattern in a contained area at a time (a few feet) that's great for corners and for spot cleaning. However, the pattern is a little too patterned and it may get stuck in loops, cleaning some areas several times while other areas aren't cleaned. If you have wide open rooms with no clutter or coffee tables/beds that enter into the central room area this won't be as much of a problem. If you do have lots of furniture or clutter, chances are eVac will miss an area or two.

The Roomba certainly uses patterns in its cleaning routine but also throws in some randomness. This prevents it from getting stuck in a loop, or covering some areas many times while missing others. Roomba may indeed cover certain areas more than others, but it will generally cover all areas and won't do the same spot five times, as can the eVac in a cluttered room.

Vacuum Power: The eVac wins. It uses a traditional vacuum motor and brush design that cleans well, especially on carpet. As a result its also louder than Roomba. The Roomba Discovery has a 2x more powerful vacuum than the original Roomba line. While that vacuum motor isn't as strong as eVac's, it makes up for it by using two counter-rotating beater bars that do an excellent job of getting dirt off the floor and into the vac.

 Here's the surpising part, though eVac has a stronger motor, Roomba got both hard and carpeted floors cleaner!

Hard floors vs. Carpet: Roomba is better on hard floors, picking up more dirt and dust bunnies. Since the eVac uses a conventional upright vacuum design, it doesn't get hard surfaces as clean as Roomba which uses counter-rotating brushes and a rubber squeegee to pick up dirt.

Despite its powerful motor, traditional upright vac and roller design, the Sharper Image eVac lost out to the Roomba on low and medium pile carpets. I was truly surprised that rugs were cleaner after the Discovery had vacuumed them, and looked better too since Roomba raises the piles as it goes.

Not that the eVac does a bad job on carpets- it does a very decent job. But after it had vacuumed a room, I set Roomba to vacuum the room again and it picked up a decent amount of additional cat hair and some dirt the eVac had left behind. In contrast, eVac coudn't pick up any additional dirt or hair when cleaning a room just vacuumed by Rooma. 

Time to Clean: Both take about the same amount of time to clean a room. They approach the task differently however. Roomba Discovery determines the size of a room by tracking distances traversed across the room, perimeter length, number of furniture or items it encounters and the amount of dirt (how often the Dirt Detector is triggered). In our tests, it spent about 30 minutes cleaning a 10 x 15 foot room with some center furniture and hardwood floors. It spends longer on carpet, making sure to cover each area twice.

The Sharper Image eVac has three timer settings: 15, 30 and 45 minutes. It's up to you to decide how much time is best for a given room. Is that a bad thing? You're still much smarter than a robot, so your guess is probably as good as the vacuum's and all affordable robot vacs do seem to spend more time than necessary on a room when left to their own devices. But if you don't want to watch the vac clean a room a few times to determine how much time is right, and don't want to check the floor closely to determine just how dirty it is, the Roomba has an advantage for unattended operation.

Room Containment: The Roomba uses Virtual Wall Units, and two are included with the Discovery. These use IR beams to create an invisible line the robot won't cross if you wish to contain it to a certain area or room. The beam is strong and works up to 15 feet.

The eVac comes with 4 red traffic cones which must be spaced up to 12" apart. The vac will bump into the cones and turn away, just as it does when it hits a wall or furniture. Certainly the Roomba solution is more cool and high tech. It's also better if you need to block off a long opening or divide a room in two since each unit has an approximate 15 foot reach. With four cones, you can block a 5 foot area. Sharper Image doesn't sell additional cones at the moment, so if you need to block larger areas, you'll have to place boxes, heavy books or other objects along the path you need to block.

Clearance: While both are quite low, the Roomba wins since it's less than 3" tall and fits under every piece of furniture in our house and under our kitchen kick boards. The eVac requires 5 1/2", and makes it under some but not all furniture.

Battery Life, Charging Times and Cleaning Times: The Roomba is the clear winner. While the eVac has a powerful traditional vacuum motor, it sucks more power. Both batteries are similar in capacity and physical size and both are NiMH. The eVac manages about 30 minutes, even on hard surfaces where the brush is turned off, and the Roomba Discovery can clean for 1.5 hours on a charge. It cleaned our 1,200 square foot home, half hard flooring and half medium pile carpet with several years wear (lowered pile in some areas) and had power remaining.

Roomba Discovery also wins on charging time, taking only 3 hours to charge a fully depleted battery. The Sharper Image eVac requires 6 hours to charge a fully depleted battery.

Return to charging base: Only the Roomba Discovery and Discovery SE have this feature. When it's done cleaning or runs low on a charge it will reliably return to the charging base if it's in the same room. If the charger is several rooms away, it won't make it, but if it's one small room away (door open of course) it seems to return to base about 65% of the time. This feature is only useful if Roomba is cleaning in the same room as the charger, or is no more than one small to average size room away.

If you have a large home or want to clean an entire floor of your house in one session, the eVac might not make it. The Roomba certainly will unless you live in a mansion.

Does it know where dirt is? Neither use very sophisticated robotics (that's why they aren't $2,000). They do not litterally see dirt using optical sensors. However, the Roomba Discovery series have a Dirt Detector feature which is new for iRobot and is not found even on expensive units like the Electrolux Trilobite or Friendly Robotics vacuum. It can sense heavy concentrations of dirt (even fine dirt). When it does so, the Dirt Detector light will illuminate and it will spend extra time cleaning that area. This reduces frustration and obviously makes for a cleaner house. Nothing is more frustrating than watching a robot vac cluelessly traverse a major mess, leaving half the dirt behind. That's why most robot vacs are designed to cover the same area more than once and spend a long time cleaning: they have no clue whether the floor is still dirty, so overkill is a must.

Remote Control: Both come with one. The eVac's is a pretty red that matches the vacuum (hey, looks do count). Both are equally useful, but the eVac has a few more functions and works via RF (radio frequency) rather than IR (infrared). RF is nicer because line of site between the remote and vac isn't necessary as it is with IR. You can indeed, start your e Vac when it's in the next room. You can also send it in any of four directions using a joystick, while the Roomba only goes in one of three directions (it doesn't do reverse, but will rotate in a complete circle to change directions). Using the eVac remote you can turn off the vacuum motor and still send the unit to another location, a la a remote control toy car. Useful? You decide!

Dirt Bin Size: They are equal.

Maintenance: While first generation Roomba's were a pain thanks to two dirt compartments, a vac intake compartment and brushes to clean, the Discovery is much better. There's only one bin to empty and it slides out easily for dumping over the nearest garbage pail. The brushes still require occasional cleaning but are easy to pop out and replace. The brush housings won't melt down due to hair build-up as they might on the original Roomba.

The eVac is a no-brainer to maintain. You don't need to clean its single brush but the eVac's brush isn't nearly as fancy or effective. It's designed like a standard vacuum beater bar with a few thin strips of brush material while the Roomba has a roller that's completely covered with brush material. Dust and dirt do tend to hang tenaciously to its filter and that's more messy to clean compared to Roomba' s filter.

Roomba's underside picks up dust, likely due to static while the eVac's underbelly stays quite clean. The large wheels and cleanly designed wheel wells don't accumulate lots of hair, while the Roomba's wheel wells do require an occasional cleaning if you have pets.

Both use replaceable filters and come with two spare filters. They are washable paper-like elements that need to be replaced every few months when their pores become hopelessly clogged. The flat filters on both models are inserted into the dirt hopper.

Mobility (carpet pile, area rug challenges): the eVac wins thanks to its large 5" wheels and strong motor. This guy is an off-road demon that rarely gets hung up on area rugs, fringes or electric cords. The Roomba is more picky since it has less ground clearance, very aggressive counter-rotating brushes, a height adjusting vacuum that hugs the floors and a side spinning brush that can occasionally lift an area rug.

The down-side is that the eVac doesn't clean hard surfaces quite as well since it has higher ground clearance, less aggressive brushes and doesn't adjust for floor heights. In other words, it doesn't get quite so down and dirty on hardwood floors and tiles. The upside is that you needn't clear away as many cords or area rugs. I hardly had to move a thing to accomadate the eVac while I really had to neaten up all cords and tuck them away, and pick up one of our fringed oriental rugs.

Warranty: Both units have a 1 year warranty.

Conclusion: In only someone could merge these two vacuums! We can always dream. . . but some features are mutually exclusive. For example, big wheels and resulting agility mean the unit can't go under low pieces of furniture.

The Roomba Discovery cleans so well on hard and low to mid pile carpeting that I don't feel a need to drag out the 12 amp Hoover upright. The e Vac does a good enough job of lifing dirt and covering the floor that I would use the Hoover every two weeks to do a deep cleaning and tidy up spots that the unit missed.

The eVac's strong points are it's powerful (by battery powered standards) vacuum and all-terrain vehicle nature that allows it to easy deal with area rugs and cords. However its battery life is pretty poor, and Sharper Image doesn't yet sell spare batteries or standalone chargers.

The Roomba is a champ thanks to its great room covering algorithm, excellent battery life and fast charging times. It also fits where most fearless flesh and bones vacuumers fear to tred and often neglect. iRobot sells all sorts of accessories and spare parts, so you can get extra base stations, batteries, chargers and more.

Roomba is designed by iRobot, a company devoted to robotic devices for consumers and the government. The Sharper Image eVac's robotic brains come from Evolution, a respected and talented robotics firm.

If you need to do localized cleaning on carpets, go with the eVac. If you have lots of area rugs and fringes or cords on the floor, also go with the eVac since it won't tangle with these. If you need a set-and-forget 'Bot that can clean an entire floor of your home on a charge, and even return to its base station to charge at the end or in the middle of a cyle, then consider Roomba Discovery. If you have lots of hard flooring, also consider the Roomba which gets these very clean.

List Price: Roomba Discovery: $249, Sharper Image e Vac: $199

Discuss this comparison: http://everydayrobots.com/forum/viewtopic.php?t=2