JIMMY R9 review: Osmosis filter with hot water function put to the test

JIMMY R9: Filter system

JIMMY's marketing boasts about a "7-stage cleaning system." However, upon unpacking and opening the service flap, we find three physical cartridges. This isn't deception, but rather common practice to combine several stages into one module.

1.  Cartridge (composite filter): A combination block consisting of a microfiber sediment filter (against rust, sand) and a first activated carbon stage (against chlorine, odors). Lifespan: approx. 12 months.
2.  Cartridge (RO membrane): The heart of the system. A reverse osmosis membrane with a pore size of 0,0001 microns. Here, everything larger than a water molecule is physically blocked: heavy metals, bacteria, viruses, PFAS, and yes, even limescale. Lifespan: approximately 24 months.
3.  Cartridge (post-filter): An activated carbon block made from coconut shells, referred to as a "mineralized filter." This stage enhances the taste and is intended to add a few minerals (presumably calcium/magnesium) in homeopathic doses to the "dead" reverse osmosis water to stabilize the pH value and smooth the taste. Lifespan: approximately 12 months.

A fourth physical component is a UV-C lamp. This is located in the unit and shines directly into the 1-liter pure water pitcher (the jug). Its purpose is to keep the already filtered, clean water in the reservoir permanently germ-free and to prevent recontamination, for example, through the outlet.

JIMMY R9: Everyday Life in Detail

Setup is incredibly easy. Simply place the unit, fill the removable 5-liter raw water tank, and plug it in. The R9 will then begin filling the 1-liter Tritan plastic pitcher. A second pitcher for the refrigerator is included.

As soon as the pitcher is inserted, the device automatically begins the filtration process. If water is drawn again later, whether hot or cold, the filtration restarts without the need to press a button. The pitcher therefore remains full as long as there is sufficient water in the raw water tank.

To completely fill the 1-liter pitcher, the internal booster pump rattles away for a good 3,5 minutes. The noise is a noticeable, high-pitched whir, louder than a modern refrigerator, but quieter than a hand blender. Anyone who needs a liter of cold, filtered water quickly in the morning will have to plan ahead.

The 2200-watt instant water heater is very useful, making a kettle unnecessary. Using the easy-to-read touchscreen, you select the desired temperature and amount, press start, and in less than three seconds, the water shoots into your cup with a short, hissing sound as the heating element starts up. No preheating or long waiting required.

•  Baby water (45°C): This setting is a godsend for parents. You hold the bottle under the spout, select 120 ml, and get perfectly tempered, clean water. No waiting, no mixing, no fumbling with a thermometer at three in the morning.
•  Green tea (85°C) or black tea (98°C): Green or black tea is available at the touch of a button. Waiting for the kettle is completely eliminated. The appliance heats precisely the selected amount, from 60 ml to 500 ml.

The soft lighting at the outlet is actually helpful to avoid missing the target at night without illuminating the kitchen as bright as day.

JIMMY R9: TDS measurement

The R9 has TDS sensors at the inlet and directly after the RO filter. The measurement is displayed on the touchscreen and shows the TDS value before and after reverse osmosis, but before the water passes through the remineralizing filter (filter 3). TDS stands for Total Dissolved Solids, meaning the total amount of dissolved solids in the water. We compared the R9's reading with that of our calibrated measuring device.

 Initial situation (tap water, Saarland, hard): 

• TDS meter: 321 ppm (parts per million)
• Jimmy R9 display: 351 ppm

 Result (Filtered water, 1L pitcher): 

• Jimmy R9 display: 3 ppm
• TDS meter: 19 ppm

The RO membrane does an excellent job, demonstrably reducing dissolved substances by over 95%. The filtered water tastes significantly softer, almost neutral. It tastes neither "dead" nor acidic, which is often noticeable with pure reverse osmosis water. Our measurement refers to the remineralized water from the pitcher, hence the slight discrepancy.

Incidentally, reverse osmosis requires wastewater. The 3:1 purification-to-drainage ratio is excellent for a countertop unit and is achieved by the pump, which forces the water through the membrane at high pressure.

The "wastewater" isn't wastewater in the traditional sense, but rather a concentrate. The R9 doesn't discard it; instead, it enriches it in the 5-liter raw water tank. Only when the TDS concentration in the raw water tank exceeds a threshold (measured by the input sensor) does the device display a "Change Water" message (exclamation mark symbol on the display). In our tests, we had to empty and refill the 5-liter tank after approximately 3-4 refills of the 1-liter pitcher.

JIMMY R9: Ongoing Costs

No filter is without ongoing costs. JIMMY charges around €122 for the filter set (1x M2S compound filter (€31,99), 1x Q2S post-filter (€34,99), 1x RO membrane (€54,99)). The compound filter and post-filter must be replaced annually. The RO membrane is designed for 3.600 liters and only needs to be changed every two years. The R9 displays when a replacement is due.

The annual cost is approximately €94,48, or €7,87 per month. Carrying crates of bottled water from a discount store is marginally cheaper, while premium water is significantly more expensive. Replacement filters are available, among other places, directly from [the retailer/store name]. JIMMY's shop or on Amazon.

In addition to the filter costs, there are also ongoing electricity costs. We connected an energy meter for measurement, which yielded the following readings:

•  Standby (display off): 1,3 watts
•  Standby (display on): 2,3 watts
•  Water production (filtration): 28,2 watts
•  Cold power consumption: 22 watts
•  Output (hot, 98°C): 2422 watts

The 2422 watts seem high at first glance. However, they are used efficiently. A kettle might only use 2000 watts, but it takes minutes to heat the water and often heats more water than necessary. The R9 heats only the selected amount in seconds. The annual electricity costs for continuous operation are therefore approximately €25-35.