Hitachi Dodai FrostWash 9000
(1 reviews)
Hitachi's reversible split air conditioner that cleans itself thanks to FrostWash technology, for a bedroom or office up to 30 m².
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Key features
- Power: 2.50 kW cooling / 3.40 kW heating (9000 BTU/h)
- Type: Reversible split, self-cleaning FrostWash
- Noise level: From 22 dB(A) indoors (quiet mode)
- FrostWash: removes 91% of bacteria and 87% of mould
In detail: Hitachi Dodai FrostWash RAK-25REF/RAC-25WEF, reversible split air conditioner 9000 BTU
The Hitachi Dodai FrostWash RAK-25REF/RAC-25WEF is a reversible fixed split air conditioner built around a feature that's rare at this price point: self-cleaning. Its FrostWash technology regularly freezes and then defrosts the indoor unit's heat exchanger, which loosens built-up dust, bacteria and mould, up to 91% of bacteria and 87% of mould according to the manufacturer. A genuine plus for indoor air quality, with no extra manual maintenance to plan for.
On performance, the unit delivers 2.50 kW nominal cooling (9000 BTU/h, Class A++, SEER 6.10) and 3.40 kW heating (Class A+, SCOP 4.20), suited to a room of around 20 to 30 m². R-32 refrigerant runs the circuit, with an EER of 3.57 and a COP of 3.86, solid figures for this price segment. The indoor unit drops to 22 dB(A) in quiet mode and stays under 40 dB(A) at full fan speed, with the outdoor unit at 47 to 48 dB(A).
The indoor unit's compact chassis (78 cm wide) makes it easier to fit above a door, and the fan motor can be removed without taking out the heat exchanger, a genuine plus for future servicing. A 12-hour timer and a Leave Home function, which maintains a minimum 10°C (50°F) in heating mode while you're away, round out the feature set. WiFi remains optional via the AirCloud Home app, compatible with Alexa and Google Home, rather than standard equipment.
Like any split air conditioner, it's made up of an indoor and an outdoor unit connected by a refrigerant line, up to 20 metres long without an additional gas charge. Bracket fitting and drilling can be prepared in advance, but commissioning must always be carried out by a certified professional qualified to handle R-32 refrigerant gas, a regulatory requirement across Europe.
For anyone after an affordable fixed air conditioner with a genuinely differentiating hygiene feature rather than a marketing buzzword, the Dodai FrostWash remains a solid option against better-known names on the market, as long as you accept the brand's still-modest online presence for this specific model.
Technical data
Detailed characteristics (EAN: 8059657001481)
Performance
| Type?General technical category the unit belongs to (portable, split, evaporative...). | Reversible fixed split, heat pump (indoor + outdoor unit), self-cleaning FrostWash |
|---|---|
| Cooling capacity?The unit's cooling power, expressed in kW or BTU/h (British Thermal Unit per hour). | 2.50 kW nominal (9000 BTU/h), range 0.90 to 3.10 kW |
| Heating capacity?The unit's heating power, for reversible models working as a heat pump. | 3.40 kW nominal, range 0.90 to 4.40 kW |
| Energy class?European energy efficiency class (from A+++ to G), showing how the unit's consumption compares with similar models. | A++ cooling, A+ heating |
| SEER?Seasonal Energy Efficiency Ratio: the higher it is, the more efficient the unit over a full season of use. | 6.10 |
| Refrigerant?Gas used in the cooling circuit. R290 and R32 are now favoured for their lower environmental impact. | R-32 |
| Indoor unit noise level?Noise emitted by the unit, in decibels (dB(A)). As a reference, a normal conversation is around 60 dB(A). | 22 to 40 dB(A) cooling, 20 to 41 dB(A) heating, sound power 54 dB(A) |
| Outdoor unit noise level?Noise emitted by the unit, in decibels (dB(A)). As a reference, a normal conversation is around 60 dB(A). | 47 dB(A) cooling, 48 dB(A) heating |
| Maximum refrigerant line length?Gas used in the cooling circuit. R290 and R32 are now favoured for their lower environmental impact. | 20 m without additional gas charge |
| Recommended room size?Room size or volume the unit is designed for, according to the manufacturer. | About 20 to 30 m² (215 to 325 sq ft) |
Features and connectivity
| Functions?Operating modes offered by the unit (cooling, fan, dehumidifying, heating...). | Cooling, heating, fan only, dehumidifying, FrostWash self-cleaning |
|---|---|
| Connectivity?Ways to control the unit remotely (mobile app, WiFi, voice assistants...). | WiFi optional via the AirCloud Home app, compatible with Alexa and Google Home |
| Timer?Programmable delay for the unit to switch on or off automatically. | 12 hours |
| Away function?Operating modes offered by the unit (cooling, fan, dehumidifying, heating...). | Maintains a minimum 10°C (50°F) in heating mode (Leave Home function) |
Dimensions and power supply
| Indoor unit dimensions?Width, depth and height of the unit (W x D x H). | 21.5 x 78 x 28 cm (depth x width x height) |
|---|---|
| Outdoor unit dimensions?Width, depth and height of the unit (W x D x H). | 27.8 x 66 x 53 cm (depth x width x height) |
| Weight?The unit's weight, an important factor for a portable air conditioner regularly moved between rooms. | 7.7 kg (indoor unit), 23.7 kg (outdoor unit) |
| Power supply?Electrical voltage and frequency required to run the unit. | 220-240V~, 50Hz |
Additional information
| SCOP | 4.20 |
|---|---|
| EER | 3.57 |
| COP | 3.86 |
| Pipe diameters | 1/4" (liquid) and 3/8" (gas) |
| Operating range (cooling) | -10°C to 43°C (14°F to 109°F) |
| Manufacturer warranty?Period during which the manufacturer commits to repairing or replacing the unit in case of failure, excluding damage or misuse. | 3 years on parts, 5 years on the compressor |
Comparison
In the 9000 BTU segment, the Hitachi Dodai FrostWash regularly comes up against the Mitsubishi Electric MSZ-HR25VF, another well-regarded 9000 BTU split known for its reliability, in searches like "Hitachi vs Mitsubishi 9000 BTU air conditioner". Here is how the two compare, based on the public specifications of both manufacturers.
| Criterion | Hitachi Dodai FrostWash | Mitsubishi MSZ-HR25VF |
|---|---|---|
| Cooling capacity | 2.50 kW (9000 BTU/h), SEER 6.10 | 2.5 kW (9000 BTU/h), SEER 6.2 |
| Heating (reversible) | Yes, 3.40 kW, SCOP 4.20 | Yes, 3.2 kW, SCOP 4.3 |
| Indoor noise level (min) | 22 dB(A) | 21 dB(A) |
| Self-cleaning | Yes, FrostWash technology (freeze/defrost) | No |
| Typical price | ≈€618 | ≈€720 to €750 |
In short, the Mitsubishi MSZ-HR25VF offers a slightly lower noise floor and a marginally higher SCOP, two genuine advantages. The Hitachi Dodai FrostWash answers with a lower price and, above all, its FrostWash self-cleaning technology, a feature the Mitsubishi doesn't offer on this range, a real plus for long-term air hygiene.
Related video
Video: Hitachi FrostWash Air Conditioner - Published on 27 June 2019
Our tester's verdict: Christophe Delpuech
Fitted recently for a homeowner who wanted to equip a 22 m² bedroom without overspending. The Dodai's compact chassis genuinely helps when mounting above a door, a real space saver on this job. Once the line was run and the unit commissioned, the room dropped from 28 to 21°C (82 to 70°F) in about twenty minutes, with a measured noise level around 38 to 40 dB(A) on high fan speed, matching the manufacturer's figures. The real standout is the FrostWash cycle: when the unit shuts down, you can watch the heat exchanger frost over and then defrost, flushing out a good share of the built-up grime, a simple mechanism but one that clearly cuts down on the musty smell you get from splits that never get serviced. My one gripe: no WiFi as standard, you need to add the optional AirCloud Home module if remote control matters to the customer, and the English documentation is thinner than what Daikin or Mitsubishi provide. For a contained budget and a genuine focus on air hygiene, this Hitachi remains a solid pick.
Frequently asked questions: Hitachi Dodai FrostWash RAK-25REF/RAC-25WEF, reversible split air conditioner 9000 BTU
It's a self-cleaning cycle: the unit freezes and then defrosts the indoor heat exchanger, which loosens up to 91% of built-up bacteria and 87% of mould, with no manual maintenance required.
Yes, this is a reversible model: alongside cooling (2.50 kW, Class A++), it works as a heat pump with 3.40 kW nominal heating output, Class A+ and a SCOP of 4.20, for year-round use.
No, WiFi isn't built in as standard: it requires the optional Hitachi AirCloud Home module, compatible with Alexa and Google Home, to control the unit remotely.
The manufacturer recommends this model for a room of around 20 to 30 m² (215 to 325 sq ft), suitable for a bedroom, home office or small living room.
The unit is covered by a 3-year manufacturer warranty on parts and 5 years on the compressor, under the standard terms applied to the Dodai range.
Bracket fitting and site preparation can be done in advance, but commissioning (vacuum pumping, connecting the R-32 refrigerant) must always be carried out by a certified professional, as required by European F-gas regulations.
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Page published on 3 August 2026