The Best Robot Vacuum I’ve Ever Tested Is 40% Off Until Prime Day Ends Tonight
Prime Day 2025 ends tonight, and before it’s over, Lifehacker is sharing the best sales based on product reviews, comparisons, and price tracking tools.
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Robot vacuums tend to work best in homes that are clutter-free: no cords, big open spaces, no piles of stuff on the floor. Robot vacuums are best at handling dust or just some basic dirt. But most people’s homes aren’t like that: They have pets. They have kids. They have small houses filled with stuff. Most people buy a robot vacuum in the vain hope that it will just take care of the floor without any help. Most robots get stuck in all that mess, and you have to spend all your time clearing them out or pulling them out of where they’re stuck — and you still have to keep a broom and mop handy to help the robot. The 3i S10 Ultra is different.
The best part about the 3i is that you don’t have to change the water because it does it for you. The robot boils the water when it returns to the dock, and the resulting distilled water is sanitized and ready to use. If the robot runs out of water, it replenishes it with a built-in dehumidifier. I haven’t changed the water once.
But as convenient as it is, it wouldn’t mean much if the robot couldn’t clean. The 3i S10 was the first robot I tested that could lift large chunks of mulch and clumps of pet toys off the floor into the vacuum without rattling or clogging it. Then, when it was docked, the turret would pump out the debris. The 3i has two large scrapers at the front of the robot that counter-spin to move the debris toward the rollers. One roller is amazingly efficient at lifting debris off the floor and into the vacuum, which uses 13,000 Pa of suction to suck it all up. That’s not much, even for today’s premium robots, but it works here. Plus, it’s quiet. Pure bliss.
Then comes the mop. The roller mop, which I increasingly like more than any other, and it did a great job, even on the first try. The robot’s navigation was also efficient, making its way through cords, paw mazes, and dog toys under my couches without issue. It didn’t get stuck in piles of laundry, but avoided them. It knew which dog toys to avoid, and which were just lint to be vacuumed up until they disappeared.
There are a few caveats: first, the tower weighs a ton — about 22 kg. You won’t want to move it once it’s installed. Also, the robot itself is tall — over 10 cm — and the mop doesn’t use hot water, but regular distilled water. Also, 3i is a new company, so that might be a concern. Personally, I didn’t notice any of these issues and they didn’t affect the result — the floor was clean.
There are cheaper vacuums on sale this week, but they’re still more expensive than the 3i S10. For example, I’d recommend it over the Saros 10 , 10R , or Dreame X50 , which I like and are considered premium robot vacuums. The 3i S10 is usually $1,899.99, but right now it’s just $1,199.99 ($1,139.99 if you use the extra coupon S10USAVE5 at checkout). Yes, it’s still pricey, but with a sale like this, it might be worth the extra splurge.
Looking for something different? Retailers like Walmart, Best Buy, and Home Depot are running Prime Day sales that are especially helpful if you don’t have an Amazon Prime subscription.
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Walmart’s Prime Day sale starts at midnight on July 8 and includes discounts of up to 50% . It’s an especially great deal for those with a Walmart+ subscription.
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Best Buy’s Prime Day sale , Black Friday in July, runs through Sunday, July 13, and is one of the best tech deals online . It’s an especially good deal for My Best Buy Plus or Total members.