A well-priced robot vacuum and mop with a self-empty docking station.
The Hoover HG4 Hydro Pro, and the other models in the range, are well-priced and good for general vacuuming on carpets and hard floors. This version comes with a basic mop, which is only really good enough for light messes, and a useful self-empty station. Spend a bit more and you find robots that mop better, but for regular vacuuming this model is a decent budget option.
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Low cost -
Decent vacuuming -
Good edge performance
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Very basic mopping -
More powerful competition is only a bit more expensive
Key Features
Introduction
Although the company is well known for its vacuum cleaners, which can legitimately be called ‘hoovers’, the Hoover HG4 Hydro Pro is the first robot vacuum cleaner I’ve seen from the company.
An entry-level model, this robot still manages to pack in a mopping option and a self-empty docking station. It’s not a bad performer, but the competition at this price is exceptionally tough.
Versions
There are three versions of the HG4, of which I have the high-end Hydro Pro. This model, the HG4 Hydro Pro (£349.99), has the clip-on Hydro Mop and comes with the self-empty station. There’s then the HG4 Hydro (£299), which drops the self-empty station but has the mopping attachment. Finally, there’s the HG4 (£249), which is a vacuum-only robot. Suction power and vacuuming ability remain the same between models.
Design and features
- Self-empty station
- Add-on mop bracket
- App control
The Hoover HG4 Hydro Pro is quite a compact robot vacuum cleaner. The dock is a self-empty one, which is also considerably smaller than the docks that come with self-empty, self-clean models, such as the Eufy Omni S1 Pro. If you don’t have much space but want a robot that will empty itself, the size of this robot may make it a good choice for you.
The docking station takes large 3-litre dust bags, and Hoover provides two in the box. Judging from previous robots that I’ve reviewed, a dust bag should last for around two months before needing to be changed. Replacements cost around £12 for a pack of four.
The robot vacuum itself is pretty much what I’ve come to expect from a robot. It’s round and has a LiDAR dome on top for fast and accurate navigation. As this is a cheaper robot vacuum cleaner, there’s no camera at the front for obstacle recognition and avoidance sp you’ll need to tidy up to a degree, before you can set this robot off on a job.
There are two buttons on this robot: one to start or pause a clean, and one to send the robot back to its dock. They’re handy if you want to start a clean and don’t want to fish your phone out.
At the rear, there’s a pull-out bin, which holds the robot’s filter (the bin and filter should be cleaned out monthly).
Flick the robot over and underneath you’ll see a standard brush for agitating dirt and a side brush for flicking dust out of the edges of rooms.
For mopping mode, there’s a clip in mopping bracket, which has to be filled with 300ml of fresh water. Hoover provides a spare mopping cloth in the box, so you can switch a dirty one out for a clean one after finishing a mopping session.
This robot doesn’t have the ability to lift its mopping pad when it goes over carpet, similar to the Roborock Q5 Pro. If you have mixed environments and need a more capable model, the Xiaomi Robot Vacuum X20 Pro is a better choice.
Control of the robot is not via the hOn app, which is home to all of Hoover’s other smart appliances, but via the HG Robots app instead. Once connected, the robot needs to go for a mapping run, so it can map out your home.
Similar to other robots, after an initial mapping run, the Hoover HG4 Hydro Pro will assign rooms to the map. The map’s not as clean as on Roborock’s app, but the general room layout was about right.
It’s easy to split or merge rooms, and I could also set a preferred cleaning order, and set cleaning settings per room.
There’s an option to add no-go or no-mop zones, the latter of which is useful to stop the Hoover HG4 Hydro Pro from wandering over carpet when its mop pad is attached.
Once everything is set up, the robot can be told to clean everywhere, or you can select a room or area to clean. For room or area cleaning, you can tell the Hoover HG4 Hydro Pro to take one or two passes.
Each cleaning option has customisable cleaning preferences, with a choice of five vacuum settings (Closed, Low, Medium, High and Max), and four water levels (Off, Min, Mid and Max).
The Closed option effectively gives you a mop-only clean, while turning the water off gives you a vacuum-only option, albeit with the mopping cloth being dragged around.
Finally, there’s a comprehensive scheduling option, so you can get the Hoover HG4 Hydro Pro to clean where and when you want.
Performance
- Decent vacuuming
- Good edge cleaning
- Very basic mopping
I set the Hoover HG4 Hydro Pro off in vacuum-only mode to see how well it could pick up the spills I’d put around the Trusted Reviews Home Tech Lab. I started with the flour spill on my test carpet.
Set to Max and with two passes, the Hoover HG4 Hydro Pro did a reasonable job of this tough spill. There’s a big lump of mess that the robot couldn’t deal with, but this is a tough mess and the budget cleaner would do well with regular spills. This result is similar to that from other budget cleaners, such as the Roborock Q5 Pro and the Robot Vacuum X20 Pro.
On the hard floor, the similar level of flour was collected with ease, without a trace of it left behind.
Edge performance was also pretty good. Sure, there was some flour right up at the plinth, but the majority of it had gone. Considering that this vacuum cleaner doesn’t have swing-out edge brushes, it’s a good result.
Mopping performance isn’t great, across all of my test stains. I started with my dried-on coffee stain. Even after two passes and the maximum water setting, the Hoover HG4 Hydro Pro struggled to remove everything.
It was the same with my red wine stain. Some was removed, but there was a lot left behind.
For the really tough stains, the Hoover HG4 Hydro Pro struggled. With dried-on ketchup, the robot couldn’t remove the mess, barely touching it.
Similarly, with the dried-on mud stain, I found that the HG4 picked a bit up but left a lot of mess behind.
For lighter stains, the Hoover HG4 Hydro Pro is fine but if you’ve got tougher messes to deal with then you’ll need a robot vacuum cleaner that can properly scrub the floor.
I also tested the HG4 with human hair. While the hair was removed from the floor, strands were tangled around the floor brush. If you’ve got a lot of hair in your home, an anti-tangle robot will make more sense.
Battery life is rated at two hours on the lowest setting. Stick the power up, and the Hoover HG4 Hydro Pro will run out faster. Even so, it had enough power to tackle the Trusted Reviews Home Technology Lab twice on higher power levels; the lab’s footprint is larger than the typical floor area of a UK home.
I measured the robot at a low 58.2dB, which makes it one of the quietest robots that I’ve tested and not at all annoying to have on whilst in the same room.
Should you buy it?
Buy if you want a decent budget cleaner for mostly vacuuming
In vacuum mode this model is pretty good, and the self-empty station useful; you can save money by choosing the standard vacuum-only HG4, which needs manually emptying.
Don’t buy if you want better mopping performance
Mopping is basic and good for only light messes, and the robot can’t lift its mop to move over carpets. For better mopping and carpet options, take a look elsewhere.
Final Thoughts
The Hoover HG4 Hydro Pro and, by extension, the HG4 range, is a pretty good set of budget robot vacuum cleaners. I don’t think that the mopping option is particularly good however, so you might want to save some money by buying the standard HG4, which can’t mop and doesn’t have the self-empty station.
If you want a budget robot vacuum cleaner that can mop better, the Xiaomi Robot Vacuum X20 Pro costs just a little more, and it has a self-empty, self-clean docking station.
If you’ve got more budget, then take a look at our guide to the best robot vacuum cleaners to help you find the right one for you.
How we test
We test every robot vacuum cleaner we review thoroughly over an extended period of time. We use industry standard tests to compare features properly. We’ll always tell you what we find. We never, ever, accept money to review a product.
Find out more about how we test in our ethics policy.
- Used as our main robot vacuum cleaner for the review period
- We test for at least a week
- Tested with real-world dirt in real-world situations for fair comparisons with other vacuum cleaners
FAQs
The Hoover HG4 Hydro Pro has a self-empty station and can also mop; there’s a version without the self-empty station; and a version that vacuums only.
Test Data
| Hoover HG4 Hydro Pro Review | |
|---|---|
| Sound (high) | 58.2 dB |
Full Specs
| Hoover HG4 Hydro Pro Review | |
|---|---|
| UK RRP | £352.99 |
| Manufacturer | Hoover |
| Size (Dimensions) | 325 x 325 x 99 MM |
| Weight | 2.6 KG |
| Release Date | 2024 |
| First Reviewed Date | 27/01/2025 |
| Model Number | Hoover HG4 Hydro Pro |
| Vacuum cleaner type | Robot vacuum and mop |
| Bin capacity | 3 litres |
| Modes | Vacuum (four power modes), mop (three settings) |
| Filters | 1 (washable) |
| Run time | 2 hrs min |
| Brushes | 1x brush bar, 1x side sweeper |
| Mop Option | Microfibre mopping pad |
| Smart assistants | No |
