How to choose a robot vacuum? Suction Pa is the most impressive; only after buying five watersheds did three brands see clearly

My Mi family sweeping and mopping machine has been used for over two years. Last year, I got one for my mom's house, and recently my cousin's family also brought me in as an advisor. After picking out three machines, one thing I am most certain of is: the suction Pa that the sales assistant often mentions on the detail page and the sales assistant is actually the most useless number in the entire spec list. What truly widens the experience gap are the other five areas, one by one.

let's talk about suction first: that string of PAs is just for show

you open the detail page of any robot vacuum, the first thing that pops up is the big number: 6000Pa, 8000Pa, and now they're all going above 12000Pa. The numbers are increasing year by year, but the dust on the ground doesn't get harder to absorb each year. The Beijing Consumers Association's 2026 review included twenty mainstream models, and the conclusion was straightforward: actual cleaning performance for large particle waste is not directly correlated with the nominal suction value.

reasoning is actually not complicated. The Pa in the suction is the theoretical negative pressure limit of the fan, while cat food and sunflower seed shells on the ground are first swept up by the side brush, rolled into the air duct, and finally taken away by the fan. If any of the intermediate links are weak, the fan price of 100,000 Pa is useless. For everyday dust and debris, the 6000Pa range is already sufficient; If you have many carpets or pets, just one glance at the 8000Pa range is enough; spending any more money is just psychological comfort.

truly worth seeing are the roller brush and edge trimming. I have a cat at home. During the peak shedding season, the hair tangled around the roller brush needs to be cleaned once a week. Once, I was lazy and delayed for two weeks, and the middle section of the roller brush was wrapped in fur like a blanket, so I had to trim it for ages. Later, when helping my cousin pick out a machine, the first thing I did was the tumbling brush structure: single or double brushes, which are anti-tangle designs and much more effective than having an extra 2000Pa of suction. Another key is the edge adhesion. The two-finger-wide gray band at the base of the wall is a major challenge for all robot vacuums. Whether the brush can extend outward and the mop can reach to the corners is the key to whether your dust ring is managed by anyone. For these two, the detail page is usually hidden in the last few pages of the gallery, so you need to be patient to flip through them.

the first true watershed: navigation, laser convex hulls, and ultra-thin visual

navigation determines whether it knows the way, and this is the first hurdle between spending 2,000 yuan and 400 yuan widening the gap. There are only three types on the market: inertial navigation, laser navigation, and visual navigation. Inertial navigation relies on gyroscopes to make wild guesses, crashing wherever you go. Machines priced around 200 yuan are still in use, so buying them is like hiring a bumper car home—just pass it off.

mainstream is laser navigation. The small bump on top of the body that spirals around is scientifically called LDS LiDAR. Its advantages are precise positioning, running smoothly even in the dark, mature technology and low cost, so buying with your eyes closed is basically a safe bet. But it has an inherent problem: the bump needs to be one to two centimeters high, while bodies with bumps generally reach 9.5 to 10.5 centimeters. My mom's solid wood bed, I measured the clear height at the bottom with a ruler—11 centimeters—the number was just right. The first one almost ended up being 10.5 centimeters. It fit in, but when it came out, it stuck on the frame and left a white mark. So before buying, the first thing to do isn't check the specs, but to use a ruler to measure the clear height under the bed, sofa, and TV cabinet at home.

visual navigation takes the other extreme, with no bumps on the body and an ultra-thin body. For example, the Ecovacs DK45 reaches 5.3 cm and the Mijia ultra-thin model 5.7 cm — both are visual navigation routes that can easily crawl under the bed. The downside is that cameras can get blind in low-light environments, making it easy to get lost when cleaning with lights off at night, and monocular cameras can't accurately measure distance. If your budget allows, there are now new adjustable LiDAR solutions—you can retract it for normal times and raise it when needed—a win-win, but expensive. My mom's last model was a standard laser navigation model. She can't even say how often she sweeps under the bed, so adding 800 yuan for just two centimeters isn't worth it.

second watershed: obstacle avoidance. Having laser navigation doesn't mean you can avoid data cables

This is the easiest pitfall to fall into, and I have to mention it separately: navigation and obstacle avoidance are two different things. That laser bump is for finding directions and drawing maps; whether there's anything underfoot doesn't matter. So just because the spec sheet says "LDS laser navigation" doesn't mean it can bypass the charging cable you throw on the ground.

obstacle avoidance is roughly divided into three levels. The lowest level is infrared and mechanical collision. You can roughly see it, then hit it and then withdraw. Machines priced between 200 and 800 yuan generally use this level, and small parts like data cables are basically invisible. The intermediate gear uses structured light or ToF, which can measure the three-dimensional distance to obstacles ahead. Whether you recognize it or not, you just circle around it when you're close. The highest level is the AI vision level; the machine's camera can recognize whether it's a data cable, a sock, or a pet's waste, sorting and processing it. If your home has data cables, socks, or kids' LEGO on the floor all year round, go straight for models with 3D structured light combined with AI vision fusion. The configuration sheets for the Ecovacs X11 and Roborock P20 Max will clearly state this.

My family's lesson was the phone charging cable. The vacuum started working by itself at 2 a.m., wrapping the charging cable hanging down into the roller brush. The machine got stuck by the bed, crying nonstop. The next morning, I took ten minutes to remove the roller brush. There's an even harsher scenario for pet families: if a cat has a stomachache and hits the carpet, a machine without AI recognition drags it to wipe the whole house evenly. I've seen that scene online several times, and every time I see it, I'm glad my cat is well-mannered. So now when someone asks me how to choose, I say you first count how many small items you have on the floor at home—more than five, and prioritize obstacle avoidance budget before suction. The detail page only says "intelligent obstacle avoidance," without any technical terms, mostly just infrared mode and a quick turn.

The third watershed: base stations. Buying them feels great, but you need to settle accounts in advance

nowadays, robot vacuums are equipped with base stations, which are divided into three levels: those that only charge, those with automatic dust collection, those with washing, mop drying, and even water supply and drainage. Automatic dust collection is truly a thrill that can't be decoupled by hand—after sweeping the machine, the machine returns to the base station. The base station sucks the dust from its dustbin into a large dust bag, so you can throw it away every two or three weeks, no need to bend down every day to empty dust.

But this account needs to be settled in advance. The official recommendation is to replace the dust bag every one to two months, with the original costing 20 to 40 yuan, which adds up to 100 to 200 yuan per year; There are brands with affordable consumables, and at ten yuan each, you can keep annual costs under fifty. When I helped my cousin's family check out the machines, I specifically searched for consumables: some new models monopolize consumables, and third parties haven't caught up yet. Original dust bags sell for 38 yuan each, which is 200 yuan more expensive when bought and costs more every year. So my habit is to search for "model dust bag" before placing an order, check third-party shelves, and then decide.

water supply and drainage is another renovation issue. Base stations with water supply and drainage connect directly to the water pipes, so you don't have to carry the tank to fill or pour sewage. The experience is top-notch, but it requires reserved water inlet and drainage spaces, meaning the water and electricity levels were set up during renovation. When my cousin's new house was renovated, I left it and put it directly on the drainage board; My old house doesn't have that kind of conditions, so we can only buy the tank-type version, bringing water twice a week, and we're used to it. Models with water supply and drainage are mostly priced between 2,500 and 4,000 yuan. Before buying, check if your home has the means, so you don't find out there's nowhere to handle it only after the machine is ready.

The fourth watershed: the networking layer—if I don't write about other buying posts, I have to write about it

robot vacuums are connected devices, so this is basically a basic selection and review, but this is exactly my specialty—three things you need to know before buying.

first item: Does the distribution network recognize 5G? Most robot vacuums only recognize 2.4G WiFi. If the router uses dual-band integration, the machine will probably fail to connect or crash when connected. my home unit blew up five times in a row back in the day, the root problem was dual-band integration plus channel auto-tripping, splitting the dual-band and pinning the channel to 1/6/11 before it finally settled down. My home router setup wasn't done smoothly, so I made up for this lesson first before buying a machine.

second item: after the internet goes off, can it still work? I specifically tested this on my own machine for three days: maps, restricted zones, and scheduled tasks were all stored on the machine's local chip, so it ran even when offline, except for remote control and real-time maps. But not all models are like this; brands heavily dependent on the cloud go offline and go downhill. Before buying, just ask customer service if you can clean locally after disconnection. If you can't answer or hesitate, just skip it. I wrote the full test of this layer in the of the robot vacuum disconnection.

the third item: where to transmit the data. Switches like "Data Sharing" and "Experience Improvement Plan" in the app are left on by default, so your home layout map and cleaning habits are sent to the cloud; Models with cameras for AI obstacle avoidance require careful attention to how the camera handles the footage. When I did privacy self-check of my home cameras, I turned off each switch one by one, and also checked the robot vacuum app—turned off the ones that needed to be turned off. Besides, it at least takes up one device slot in the home router, and dozens of smart devices at home squeeze into one network, so you factor in the device load in advance.

in the end: three families, three ways to buy, one form to wrap things up

bought three machines, my biggest takeaway is: there is no best machine, only one that matches my family's conditions. Lay out the accounts for my family, my mom's family, and my cousin's family, and compare them to your own situation.

Here's the

order: first, use a ruler to measure the clear height under the bed and sofa, then look down and count how many socks are always on the floor, then search for alternatives to the dust bag on this device. Step four, ask customer service if you can clean locally after disconnecting the internet. You've passed all four checkpoints, so it's not too late to check the price later. As for suction power, 6,800 is fine, don't add money to that string of numbers.