Bosch Cool 4000
(6 reviews)
With Auto, Silent and Sleep modes switched on in one click, the Bosch Cool 4000 cools rooms up to 35m² without fiddly settings, dropping to 44 dB(A) overnight.
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Key features
- Output: 2600W (9000 BTU), up to 35m²
- Functions: 3-in-1: cooling, fan, dehumidifying
- Noise level: 44 dB(A) in sleep mode
- Auto, Silent and Sleep modes switched on in a single click
In detail: Bosch Cool 4000, 3-in-1 portable air conditioner, 9000 BTU, A+ class
Bosch extends its portable air conditioner range with the Cool 4000, a 3-in-1 model combining cooling, fan and dehumidifying functions in a single unit on castors. With a cooling capacity of 2600W (9000 BTU), it targets rooms up to 35m², bedroom, living room or home office, with no building work or fixed installation needed.
The Cool 4000's main selling point is how simple it is to use: Bosch Easy Cool Select offers three preset modes (Auto, Silent, Sleep) accessible in a single tap from the touch display or the included remote, with no need to juggle multiple fan speed and temperature settings. In sleep mode, the noise level drops to 44 dB(A), a figure that places it among the quieter units in its category for bedroom use.
Rated A+, it claims a consumption of around 0.8kWh, with up to 20% savings compared with an equivalent class A model. The dehumidifying function removes up to 50 litres of water a day from the surrounding air, a welcome addition on top of cooling during the muggiest stretches of summer. The R290 refrigerant it uses remains one of the more environmentally friendly options currently available on this type of appliance.
The 15cm exhaust hose and included window kit allow for a quick setup with no professional installation required. Its castors and side handles make it easy to move between rooms, an important point for a portable unit meant to follow demand rather than stay fixed in a single room.
The main thing to watch is price: the Cool 4000 sits in a more premium bracket than the average 9000 BTU portable air conditioner, and its street price climbs noticeably whenever summer demand spikes. It remains a solid choice all the same for anyone after a recognised brand, straightforward day-to-day use and enough quietness for overnight use.
Technical data
Detailed characteristics
Performance
| Type?General technical category the unit belongs to (portable, split, evaporative...). | Portable monobloc air conditioner, 3-in-1 |
|---|---|
| Cooling capacity?The unit's cooling power, expressed in kW or BTU/h (British Thermal Unit per hour). | 2600W (9000 BTU/h) |
| Energy class?European energy efficiency class (from A+++ to G), showing how the unit's consumption compares with similar models. | A+ |
| Recommended room size?Room size or volume the unit is designed for, according to the manufacturer. | Up to 35m² |
| Airflow?Volume of air moved by the unit each hour, in m³/h: the higher it is, the faster the room's air is refreshed. | 420 m³/h |
| Noise level?Noise emitted by the unit, in decibels (dB(A)). As a reference, a normal conversation is around 60 dB(A). | 44 dB(A) in sleep mode, up to 48 dB(A) in normal operation |
| Dehumidifying?Amount of water removed from the air by the unit, usually expressed in litres per 24 hours. | Up to 50 litres a day |
| Refrigerant?Gas used in the cooling circuit. R290 and R32 are now favoured for their lower environmental impact. | R290 (propane, low environmental impact) |
Features and connectivity
| Exhaust hose?Length of the hose venting hot air outside, usually through a partly open window. | 15cm diameter |
|---|---|
| Remote control?Method used to adjust and monitor the unit day to day. | Included |
| Timer?Programmable delay for the unit to switch on or off automatically. | Programmable |
Dimensions and power supply
| Dimensions?Width, depth and height of the unit (W x D x H). | 69 x 35 x 32cm (H x W x D) |
|---|---|
| Weight?The unit's weight, an important factor for a portable air conditioner regularly moved between rooms. | 28kg |
Additional information
| Brand | Bosch Thermotechnik |
|---|---|
| Model | Cool 4000 |
| Operating modes | Auto, Silent, Sleep (Bosch Easy Cool Select) |
| Manufacturer warranty?Period during which the manufacturer commits to repairing or replacing the unit in case of failure, excluding damage or misuse. | 2 years |
Related video
Video: Eiskalt durch den Sommer! Bosch Cool 4000 Klimagerät im Test - Published on 19 August 2025
Our tester's verdict: Christophe Delpuech
Set up in a roughly 30m² living room during a proper heatwave, the Cool 4000 did exactly what it promised: the room went from stifling to comfortable in about twenty minutes on Auto mode, with no need to touch the settings afterwards. Switched to Silent in the evening, it stays audible but sits within a perfectly liveable range for reading or watching a film; on Sleep mode, the background hum becomes almost unnoticeable once the room has cooled down. The dehumidifying function proved genuinely useful during a very muggy, stormy evening, on top of the cooling itself. The window kit takes only a few minutes to fit with no tools needed. The one real downside: it's heavy to carry alone between floors, and pricing climbs fast whenever demand spikes during a heatwave, so it's worth keeping an eye on prices before buying.
Frequently asked questions: Bosch Cool 4000, 3-in-1 portable air conditioner, 9000 BTU, A+ class
Yes, in Sleep mode the noise level drops to 44 dB(A), placing it among the quieter portable air conditioners in its class, with a gradual temperature rise built in to avoid disturbing your sleep.
Its 2600W (9000 BTU) cooling capacity is designed for rooms up to 35m², typically a bedroom, a mid-sized living room or a home office.
In standard cooling mode, most of the condensation drains away through the exhaust hose. In pure dehumidifying mode (up to 50 litres a day), the tank needs emptying more often depending on ambient humidity.
No: like any compressor-based portable air conditioner, it has to vent the hot air it extracts somewhere, via the supplied hose run through a partly open window using the included installation kit.
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Page published on 6 August 2026