Viesa Holiday IIIs 12V Air Conditioner image 1 Viesa Holiday IIIs 12V Air Conditioner image 2 Viesa Holiday IIIs 12V Air Conditioner image 3 Viesa Holiday IIIs 12V Air Conditioner image 4

Viesa Holiday IIIs 12V Air Conditioner - Installed

£2040.00 (inc VAT) 2299.99
Product Ref : 278491
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Viesa Holiday IIIs is an evaporative conditioner made in Italy, developed to cool the passenger compartment of the Motorhome using the water evaporation principle and creating a natural feeling of well-being directly on the person. In practice, it aids the evaporation of the humidity on the skin and thus removes heat from the body.

Viesa Holiday IIIs is a technological update involving almost exclusively the electronics of the renowned evaporative conditioner; it further reduces the already low power consumption and improves the system performance as a whole. The most striking news for the user involves the control and management systems, namely the panel with display and remote control, both with a new design. The brightness and contrast of the display on the equipment can be adjusted, and the display is larger for easier reading. Furthermore, it is now more intuitive and easy to read thanks to its new graphics, new icons and information that complete its improved usability. Four LED spotlights with on/off function operated by remote control.

Like its predecessor, Viesa Holiday IIIs is also entirely developed and made in Italy with Italian components and technology, with the exception of the exclusive and patented filter made up of a filament twine with three different wood types, manufactured in Argentina by the parent company Colven.

The system uses water evaporation and creates a feeling of well-being directly on the person. Like the previous model, it is designed to cool a space no longer than 8 metres and with a maximum of 4 people on board. It replaces a standard (40 x 40 cm) or midi (50 x 70 cm) porthole and is connected directly with the vehicle water system. The filtered and cooled air is supplied by 4 independent and revolving outlets with 24 different speeds and the possibility of programming the on and off times with the timer, or of activating the ventilation only (by turning the pump off). The system can monitor the battery charge and switch off automatically in case of low voltage (10.5 V). Several safety devices intervene in the absence of water (sound signal and pump self-deactivation), reversed polarity or malfunctioning of some components.

Evaporative air coolers work by lowering the perceived temperature, i.e. the heat our body feels. This value is influenced by four different factors: the ambient temperature, relative humidity (i.e. the ratio between the quantity of water vapour contained in a given mass of air, and the maximum quantity of water vapour the mass of air can contain under the same temperature and pressure conditions, measured as a percentage), ventilation, and humidity density. The Viesa evaporative conditioner controls all four of these factors to create a feeling of personal well-being, rather than on the surrounding environment. This provides a proper evaporation of humidity on the skin, a phenomenon whose effect is to remove heat. The cooling process starts with the evaporation of water from the filter surfaces, thus lowering the temperature. Cooled air then enters the cabin at an optimal relative humidity of 40–60%, and at a very low density. Stabilizing the internal relative humidity is essential, since if the air is too damp it is harder – or even impossible – to allow perspiration to evaporate. Similarly, humid air introduced at a low density (i.e. with tiny nebulized droplets measuring 0.002 microns) enables moisture to be distributed over a larger surface, facilitating faster evaporation. Evaporation is further promoted by forced ventilation from the cooler.

PLEASE NOTE: This works completely differently to a conventional roof air conditioner. Please ensure you understand the difference before you order one of these Evaporative Air Conditioners.

Professionally Installed?
There are currently six places around the country where this will be professionally installed. The air conditioner unit will be sent to the most convenient installer and you will bring your vehicle for the installation. We can let you know where these are on request.


  • 100% filtered fresh air
  • Doors and windows may remain open
  • Air humidity is partially maintained, for the benefit of those suffering from allergies or asthma
  • It reduces fumes, smell and particles detrimental to air quality
  • It can be used while travelling
  • The efficiency of the cooling system increases as the outside temperature increases
  • Low consumption, up to 80% more economical than traditional systems
  • Easy installation and minimal maintenance
  • Reduced static current
  • No air drying

Viesa Holiday IIIs 12V Air Conditioner Features

  • 12 Volt air conditioner economical to run
  • It can also be operated while the vehicle is in motion
  • Prevents excessive surges in temperature
  • Ecologically-friendly: no oil, gasses or chemical additives
  • Low power absorption: 12 volt operation (no need to have EHU or the engine running to use)
  • Silent operation: thanks to an advanced centrifugal pump
  • Healthy: purifies air through a system of filters
  • Thousands of motorhome enthusiasts in Europe confirm its efficiency
  • Creates a comfortable environment: it maintains a constant rate of humidity
  • Natural: it removes body heat through the principle of evaporation
  • Viesa brand chosen by haulage companies for trucks worldwide

Frequently Asked Questions
Does it cool like a traditional conditioner?
No. If you’re looking for a “fridge” effect VIESA will certainly disappoint you; if you’re looking for a fresh feeling of well-being, it’s ideal. The absence of this effect is a real positive characteristic, as sudden temperature changes harmful for your health - like those created by a traditional conditioner - are avoided.

Is it a de-humidifier or a humidifier?
The VIESA evaporative conditioner neither increases nor decreases the humidity; instead, it stabilizes it, keeping it stable between 40% and 60%.

Does it create condensate inside the vehicle?
No, as its exclusive evaporation system brings the humidity to a low density; the size of a nebulized drop is 1-40 microns, while that of the one created by VIESA is 0.002 microns (gaseous state).

Do the windows and the porthole have to be completely closed to keep my Motorhome fresh?
No. In fact it’s mandatory to keep a porthole open and to control humidity and air. If there is no hot wind you can keep your doors and windows completely open, still benefiting from the cooling of VIESA.

Is it suitable for everybody?
It is particularly recommended for those suffering from asthma and allergies, the elderly, adults and children and, last but not least, pets. There are many beneficial health effects, as there is no sudden temperature change and the air is suitably humidified, not too dry nor harmful.

How many models and which powers are available?
For Motorhomes, there is only the model Holiday IIIs for a length up to 8 m with 4 adults on board, as the human body releases heat and humidity, unbalancing the effect of VIESA; the presence of more people does therefore not guarantee the same efficiency.

Is a generator needed for its operation?
No, a generator is not needed thanks to its low consumption: it is directly powered by the service batteries; you are advised to recharge them using solar panels, 220 V columns, gas battery chargers, alternators, etc.

How is it installed? Is a special opening needed?
It replaces a standard porthole, 40 x 40 cm. If no porthole is available, a suitable opening with the same dimensions must be arranged.

Can it be used while travelling, too?
Yes. In any case, note that VIESA, positioned in the centre of the living space, is mostly efficient in this area, while the same efficiency cannot be guaranteed in the driving space, even if the outlets are directed forwards.70% of customers are satisfied with the result even in the driving seat, while 30% unfortunately do not obtain the same benefit.

General characteristics
Functions of the control board:

  • Display larger by 75% with adjustable contrast and brightness.
  • 24 ventilation speeds.
  • Programmable switching on and off.
  • Pump switching on and off for ventilation only.
  • Key sounds can be silenced.


  • Against polarity reversal.
  • Against short circuit, high and low consumption of the pumps.
  • Against short circuit, high and low consumption of the ventilation.
  • Against short circuit, high and low consumption of the solenoid valve.
  • Against low tension of the service battery (battery protection).
  • Against absence of water in the system (cuts the hydraulic circuit off).
  • Against unit forgotten and left on (automatic switching-off after 24 hours).

System information:

  • Installation date.
  • Serial number.
  • Firmware release.
  • Brand and model.
  • Total operation hours.
  • Maintenance indication.
  • Time.
  • Battery charge indication.
  • Remote control complete with all functions.
  • Dimmable LED lights that can be operated by control unit and remote control, with 600-lumen high brightness (option).


  • 12 V battery consumption from 0.5 to 5.8 Ah 6 to 69.6 Wh.
  • Water consumption from 0.5 to 1.5 l/h.
  • Max. air volume per minute 19 m³.
  • Weight of the complete evaporating unit 19 kg.
  • Dimensions of the evaporating unit: length 820 mm / width 750 mm / height 210 mm

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If you’ve changed your mind about keeping your purchase, please return it in its original condition with proof of purchase and we’ll exchange or refund it. Unless faulty, this should be within 30 days of receiving your order. By original condition, we’d expect this to mean that you’ve kept packaging and labels, and that the item is undamaged and unused.

For further information of how to return your item, please visit the "Returning an Unwanted/Faulty/Damaged Item" section on our Help Page.