iRobot Roomba s9 vs i7 Vacuum (2021 Comparison)

Last Updated on December 18, 2020

Roomba i7 vs. s9 at a Glance

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If you don’t have the time to read the whole article, don’t sweat it. You can just take a look through our quick list here instead, although if you’re serious about getting one, we recommend that you take a look at the rest of the article in more detail, so you can make the right decision.

Our decision about which is the better vacuum is not as clear cut as you might think.

Roomba i7 Advantages:

Cheaper
Full rotation possible with round shape
Excellent navigation

Roomba i7 Disadvantages:

Only one power setting
Shorter battery life

Roomba s9 Advantages:

Wider brush
More powerful
Larger dustbin
Longer battery life

Roomba s9 Disadvantages:

More expensive

Winner: Don’t want to read the full article? The editor’s choice is the Roomba i7.

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What’s the Difference Between Them?

These two robot vacuums are both top-of-the-line robot vacuums produced by iRobot. This means that they have a lot of similarities, from their interface to their app upgrades.

However, they also have quite a few differences that could influence your choice for which one to go for. So we’ll take you on a quick run-through down below and by the end, you should know which one will be most suitable for you.

Design

Okay, so one of the first things that you will notice about these two vacuums is that they have pretty different designs. In fact, they’re different shapes. The i7 has the classic Roomba shape in that it is a circular disc.

This allows it to have full rotation and can easily move around. However, the s9 has gone for a new look. It is no longer the circular shape that we came to associate with Roomba, but instead, it is a D-shape.

The wheels still sit on opposite sides of the circle, at the widest part. But whereas the i7 has the brush placed within the wheels, the s9 has it placed in the rectangular section at the front.

This new design means that the brush is now a lot wider than it was. It also makes the s9 quite a lot better at reaching along walls and in corners, as the brush is a lot closer to the edge of the vacuum.

Another change has occurred in terms of the side brush. On the i7, the side brush sat in front of one of the wheels. There are then three long white spokes which move at high-speed with the aim of gathering dust and debris and channel it towards the brush.

The s9 has changed this design so that the side brush is at the corner of the wide brush head. There are now five, shorter, black spokes which move at a slower pace.

The problem is that the faster speed had a tendency to cause dirt to scatter, rather than channeling it. Now that the side brush moves more slowly and is closer to the brush, it is a lot more effective at gathering the dirt.

These two vacuums are also different in terms of how they look. The i7 is a sleek black in color with a u-shaped control panel in the middle. This panel puts the three buttons, for “home”, “clean” and “spot” in the middle of the vacuum.

In contrast, the s9 has more of a matte black finish, with a plain, chrome disk in the middle. The s9 still has the same three buttons, but they’re now in the top corner rather than the middle.

They are also different sizes. The i7 is a wider vacuum, measuring 13.34 inches across, where the s9 measures around an inch less, at 12.25 inches across. However, given the placement of the brush head, the s9 still has the bigger brush. Then the i7 measures 3.63 inches in height, where the s9 measures 3.5 inches.

This is a fairly negligible difference, and they will both be excellent at getting under low-hanging furniture like beds and sofas, but the s9 will be able to go just that bit lower.

Although the i7 is bigger, it is also a little lighter. It weighs 7.44 pounds, where the s9 weighs 8.2 pounds. You shouldn’t generally have to carry it around, as it can drive itself. But if you need to take it up or downstairs frequently, the i7 is the lighter option for you.

Verdict:

Both of these designs have their merits. However, we think that the new D-shape of the s9, and the wider brush that goes with it, are a good step up from the classic round shape of the i7. For that reason, we will give this round to the s9.

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Features

If you’ve been looking into these two Roomba vacuums, you might have noticed that as well as i7 and s9, there are also i7+ and s9+ vacuums available. Don’t worry, it’s nothing complicated. The difference is actually pretty simple.

The plus models both come with a “Clean Base” station. This is a really cool feature in which the dock empties the vacuum bin. The Clean Base station can then hold up to 30 bins of dirt.

One of the big concerns of people who are looking at getting a robot vacuum is the dustbin capacity, so this is a really great way of alleviating that task. You should still clean the brush roll and filters regularly, but it means that you can set the vacuum off to clean without worry about having to empty it.

The actual dustbins of these two vacuums are quite small. The i7 dustbin can hold around 300 ml and the s9 can hold around 400 ml. So if you don’t have the Clean Base station, you’ll need to empty it fairly regularly.

The plus models are a bit more expensive though, so you probably need to think about if it’s a feature that will really enhance your life before you fork out the extra expense.

Both vacuums can also be connected to a smartphone via the iRobot Home App. Not only does this allow you to control the vacuum from your phone, and therefore pretty remotely, but you can also link them to Alexa or Google Assistant.

Not only can you use these systems to control the vacuum by voice, but on the app, you can also access the basic functions of the Roomba. You can check on its progress, although that is presumably designed for people who are doing some heavy procrastinating at work.

More helpfully, you can schedule cleaning times. This means that if you suddenly discover that you have people coming round, or if you remember that the kids trailed in a lot of dirt after soccer practice, you can send the Roomba out to vacuum, even when you’re not in the house.

Verdict:

These two vacuums share the ability to be controlled by the app and both are available with a Clean Base station, so it’s a draw for these two in terms of the features they offer.

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Navigation

The old Roomba robot vacuums used to follow a random cleaning pattern. This was a really effective way of making sure that the whole room could be cleaned, but it definitely wasn’t the most efficient way.

Sure it got everything clean, but it took a while. When you’re running off a battery, you obviously could do with the vacuuming pattern getting the room done in as little time as possible. That’s what these two newer models offer with the Imprint Mapping Technology that iRobot has developed.

Both the i7 and the s9 use this smart mapping technology and it is a real game changer. They use a camera-based navigation system, and they can then save the maps in the iRobot cloud servers.

They are able to do this with a training run too, in which they don’t have the vacuum motor switched on. It might sound pointless to have a vacuum go round the whole home specifically not vacuuming, but this allows the robot to use as little battery as possible, so that it can map the whole home in one run. In this way, the vacuum can gather data about the interior layout.

Once the robot vacuum has the data about your home’s layout, you can name the different rooms. This is what makes this mapping so special. Once the rooms are named, you are able to direct the robot to go to clean a specific room.

This can even be done with voice control if you have Alexa or Google Assistant, so if you’ve just done some baking with the kids, all you need to do is call out “Roomba, go clean the kitchen”.

It also helps with scheduling the cleaning from the app. You can schedule the robot so that it cleans the kids’ rooms after they’ve gone to school, or to clean the lounge before guests arrive.

There is also the option of creating Keep Out Zones. These virtual barriers are a really great feature if you need to keep the Roomba away from the dog food, the kids’ toys, or perhaps not get too close to the work desk.

Verdict:

Both the i7 and the s9 have the Imprint Mapping Technology, and they both have the Keep Out Zones feature too, plus they are both compatible with the iRobot Home App, so they are equals when it comes to navigation.

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Runtime

One of the main aspects that you’ll be looking into if you are considering getting a robot vacuum is battery life. For a lot of people, especially those with larger homes, it is what puts people off getting a robot vacuum.

They might argue, what is the point in getting a vacuum that clean on its own if it’s constantly running out of charge and you have to set it off again? Well, these people are right.

There isn’t much point in getting a robot vacuum that requires such a hands-on approach… but that’s not the case with these two vacuums. For starters, these robot vacuums last a lot longer than a lot of other battery-powered vacuums.

A lot of cordless vacuums can only last for around 20 minutes. Granted, they often only run while you pull a trigger, so there is little to no wasted time, but they still won’t run for long enough to get around your home.

But these two Roomba vacuums put those cordless vacuums to shame. The i7 will run for up to 75 minutes. As it only has one power setting, you can’t choose for it to use less power, but it adjusts automatically, so it should only be using the higher power output when it is necessary.

The s9 on the other hand, can run for 49 minutes on high-power, or 120 minutes on the eco setting. This is pretty remarkable. There aren’t going to be many occasions when you are going to need it on full power for the whole home, and if you do, 49 minutes should still be enough time to get it done.

However, if the Roomba runs out of time, fear not. Both the i7 and the s9 come with the Smart Charge and Resume feature.

The Smart Charge and Resume feature really sets these Roomba vacuums apart from the other robot vacuums on the market. A lot of the robot vacuums are able to send themselves back to the charge station when they are low on battery.

But these two take it a step further. Due to their smart navigation, which helps them to map the home, they are able to send themselves back to charge, and then send themselves back out to resume the vacuuming from the point they left.

This is an incredible feature as it means that it will never leave the vacuuming half done. Plus it doesn’t need to re-do sections, making it much more efficient.

Verdict:

The Smart Charge and Resume feature of these two vacuums is brilliant, and they both have an excellent battery life, but the s9 runs for an extra fifteen minutes, which could be a whole extra room, plus it can manage 49 minutes on high-power, so the s9 is the winner in terms of run-time.

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Power

There haven’t been any major differences between the two vacuums so far, except the design, so you might be wondering what sets them apart. Well, one of the major differences is power. The i7 is a powerful robot vacuum.

In fact, it is one of the most powerful on the market. It also only has one setting, that is, one setting that you can choose. The i7 then automatically adjusts the power output depending on the surface it is dealing with.

This means that on carpets it equates to a high power setting, while on hard floors it would be a lower setting. For the s9 you can choose the power setting that you want, ranging from high power to eco mode.

There is sadly no standard measure for gauging power on vacuums, but a lot of people tend to use the “cfm” of airflow, or cubic feet per metre. We can tell you that the i7 produces 17 cfm when it is on the high power, carpet setting, and this drops to a little over 6 cfm when it is on the lower, hard floor setting. In contrast, the s9 produces 22 cfm when it is set to high power, or 8 cfm on eco mode.

If we put this into real terms, it means that the i7 is great at picking up surface dirt and can deal with any surface. However, the s9 is so powerful that it can perform an excellent deep clean on carpets. Which leads us nicely onto our next section…

Verdict:

There is no doubt about it, the s9 is the definite winner of the power round. It’s the most powerful robot vacuum on the market, and while the i7 has great power too, it can’t compete with the s9 power.

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Performance

So we’ve talked about power, and we’ve talked about the navigation systems, but now it’s time for us to dig into the performance of these two robot vacuums. Firstly we need to put it out there that the robot vacuums are still playing catch-up with the upright vacuums.

They are less powerful, rely on battery power, and don’t have the human eye to check and decide to use the hand-held nozzle for the tricky spots. That being said, the i7 and s9 are truly excellent robot vacuums.

As we mentioned before, both of these Roomba vacuums are more than capable of cleaning up on any surface. However, they do have some differences. One difference is something we mentioned earlier; the side brushes.

The fast-spinning brushes of the i7 can cause dirt to scatter somewhat. Plus the low power, automatic setting of the i7 can make it difficult to pick up sand on the hard floors.

It also struggles more with long hair getting trapped on the brush, which is a bit of a problem if people in your house have long hair or if you have pets. However, the hair can be easily dealt with- you just need to check and clean the brush regularly.

The more powerful s9 is truly the top of the range in terms of robot vacuum performance. It can pick up tiny grains of sand, but it can also deal with larger pieces of debris.

Plus the slower side brushes don’t tend to push the dirt away, but instead channel the dirt towards the main brush. The s9 is also very impressive in terms of efficiency, as it has a wider brush and so it needs to do fewer journeys. Plus the D-shape means that it is better at cleaning along wall edges and in corners.

Verdict:

The i7 is a really great robot vacuum and performs excellently at cleaning various surfaces, but again the s9 is simply better.

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Price

So far in our comparison, you may have noticed that the s9 has either been better than the i7, or they’ve been the same. So you might be wondering why people would pick the i7 at all. The answer is, of course, the price.

Now we usually would point out that prices can vary, and often that can bring two products in line with each other, but that is not the case for these two vacuums. Although the prices do vary, the i7 currently costs around $400, while the s9 is currently around $700.

That is a big difference. If we look at the plus models, the i7+ currently costs around $550, while the s9+ costs an eye-watering $900. So you could get two i7 robot vacuums and still have $100 to spare for the cost of the s9+.

Verdict:

The s9 and s9+ certainly offer a lot for their price, but whether or not they are worth a few hundred dollars more than the i7 is your choice. However, there is no doubt that when it comes to price, the i7 is the better option.

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Conclusion

So to sum up what we’ve been through- both the i7 and the s9 have smart mapping, which allows them to remember the rooms of your home, be sent to particular rooms, and vacuum efficiently.

They are both compatible with the iRobot app, they both have the Smart Charge and Resume feature, and they are both available in the plus model, which comes with automatic dirt emptier. If you go for the s9, you get a more powerful motor, a wider brush, a deeper clean, better corner cleaning, and longer battery life.

Now we said at the start of this article that our choice would be the s9. While it is true that we believe that the s9 is a better vacuum, the price difference in these fairly similar vacuums is huge.

Whether or not the s9 is worth the extra expense is your call. It is certainly the better vacuum, but only you can decide if it is worth a few hundred dollars more.

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