It would seem that this idea has been taken up for those involved in outdoor pursuits and who own caravans, boats and motorhomes.

The Mobilcool sold by Espar of Plymouth is a 12v unit that requires no installation and is fitted with four cool air outlets that can direct the flow of air to where it's most needed. The unit uses cold water to provide the coolant and has a three speed fan drawing a maximum of 13.9 amps at the highest speed.

It weighs 4.4kg and stands just 400mm high. The 5.7 litre tank provides the seven hours cooling during the night and three hours during the day.

Although units using the evaporation method of cooling are low cost and require no professional installation, the main drawback is that of humidity.

If the area being cooled is closed the air will recirculate, and the humidity levels will increase significantly. The makers recommend that a window is left open to allow the escape of this water laden air.

This is an obvious and potentially significant drawback, particularly for boat owners who sometimes battle against the problems of damp.

This has not, however, stopped units of this type from being very popular on mainland Europe, where they have been used for some considerable time.

The Mobicool is new to the UK and was only taken on by Espar during the winter months so it remains to be seen how it goes during its first UK season.

So far the interest has been encouraging with Marathon adding it to its catalogue and some motorhome firms also taking up the product.

Another product that has only recently come onto the market, albeit for the heating sector, is the Hurricane 2 system. Based on the popular Canadian designed and built Hurricane heaters - a company that has been around for many years - this new version has only been marketed over the last few months.

More efficient Built in Canada and CE marked for EU use the Hurricane 2 is designed with a larger water jacket and is more efficient than its predecessor. There are two versions of the new product providing 10.3 or 14.7kW, with each drawing 6.5 amps, fuelled by diesel and having electronic ignition.

Although these units have proved popular with the inland waterways sector, it would seem that there are a number of coastal customers as well.

The majority of the units on offer are fitted by yards and builders, but the company does supply the materials for keen DIYers to retro fit these heaters. The company has seen close parallels between the canal boats and the workboats used offshore but says recent investigations proved that few workboats are fitted with anything like decent heating systems.

For this reason, they took space at last year's Seawork to promote their range and it proved successful with good levels of interest. As a result, they've taken space at this year's show in the hope of building on the initial interest shown.

This year's London Boat Show saw the launch of what Eberspacher called a new and unique product. Conceived and developed in the UK the Combitronic system comprises of the Eberspacher Hydronic 5 heater, a special drop coil technology calorifier and a blown air system that regulates steplessly and therefore is said to be very quiet.

All of this is integrated in one box 650 x 270 x 270mm that fits in a locker or in the engine compartment. An energy management unit is included within the system so that when moored it can be operated by connecting to a 220/240v connection and give hot water via an immersion heater. The optional integration of PTC heating elements makes possible a heater power of 1.5/1.8kW.

From the single source of the Eberspacher Hydronic diesel fuelled heater both space heating and hot water, via a storage boiler, can be configured. Diesel fuel is used as the energy source of the heater and is available on board from the boat's own fuel tank, so it's a more costeffective way of providing not only hot air via a fan assisted radiator, but hot water without having to run the engine.

Depending on the system installed and the ambient temperature, warm water is available within about 10 minutes, which provides enough for showering and galley use; even additional water will be heated up in a few minutes.

In connection with an ambient temperature sensor, the heater regulates itself automatically on a pre-selected temperature. The operating control contains a switch for summer/winter operation.

The alternative to the compact version is the modular option that separates the main components. This version should be chosen when installation space for the compact system is not suitable or available. According to the requirement of the boat owner, when using the modular system, boilers with volumes of 10-17 litres are said to be available.

Listening The Combitronic system starts at £1325 ex VAT and Russell Brown, MD of Eberspacher, said: "We have been listening to our customers and responded to their growing requirement of one heating system which combines all of the above features. Based on the Hydronic 5 diesel fuelled heater, the Combitronic is the perfect solution for those owners with boats up to 40ft in length who require fully automatic warm air and hot water heating (without running the engine) at any time combined with the benefit of using shore power for interior and water heating when available. Additionally, when used in conjunction with the optional Calltronic, you can even start the system using a mobile phone before you arrive at the boat."

Dometic Marine has been involved in this market for over 45 years and claims to have invented the first boat air conditioner. Its UK arm, operated by Steve Morris and Paul Hickinbotham (both refrigeration and electrical engineers) feels it is responsible for more major advances in marine air conditioning, refrigeration and sanitation system technologies than any other company in the industry.

Without doubt the company is a major supplier of marine equipment to yacht builders, military and commercial shipbuilders worldwide under the brand names of Condaria, Cruisair, Marine Air Systems, Grunert, and Sealand.

The UK team also has responsibilities to support Turkey, Russia, Ukraine, Cyprus, Malta, Portugal, Germany and Greece. However, Dometic Marine solely supplies air conditioning systems to all larger UK OEM's including Fairline, Sunseeker, Princess, Sealine and Oyster as well as a number of smaller boatbuilders and aftermarket customers covering motor or sailboats from 7.6m up to 76m.

There are new products being introduced as part of an active engineering programme for noise reduction in the company's air conditioning products. Noise abatement measures, such as sound shields, isolation rails, and sound deadening materials, are all being introduced.

During 2006 the company will launch the new DC series air handler for both Marineair and Cruisair product groups. This utilises noise reduction technology to eliminate motor hum that can occur when the fan is running at low speeds. The AC power supply is converted to DC to drive a high efficiency brushless DC fan motor.

Low profile There is also an all new low profile 16000BTU Dashair self contained air conditioner that stands eight inches tall and is specifically designed for areas where height is restricted, such as helm areas and low profile seating.

With systems able to heat while still in water conditions as low as 4infinityC Dometic feels its air conditioning system can heat or cool a boat from ambient temperatures as high as 50infinityC to as low as -5infinityC without the need for a supplementary back up systems, such as a diesel fired water heater. A claim, they say, no other marine air conditioning manufacturer can make.

For owners who want to venture outside these operating conditions, the company offers custom systems, such as electric heater barrels, resistive in-line heaters and diesel fired water heaters, that can be used in conjunction with a Dometic air conditioner.

Mention Webasto in boating circles and most people will think of the company's marine air and water heaters. Webasto has, however, recently developed new and advanced marine air conditioning systems.

Launched as the Blue Cool model ranges, Webasto tell us these units are designed for yachts and power cruisers of virtually any size.

Two of the ranges are available for retro-fitment: The Blue Cool Classic self contained range is for craft with one to three cabins. The Blue Cool Premium chiller/water range is designed for larger yachts and powercraft, as these are integrated chiller air conditioning systems.

And unveiled at this year's London Boat Show was the latest addition to the range;

Blue Cool Select, which features a central air conditioning unit that creates cool air and gathers it into a plenum chamber.

Cool air sucked This cooled air is then "sucked" from the plenum, through special smooth-bore ducting, by fans located in the cabins.

These fans have been developed to be compact, extremely quiet and can be supplied with integrated control, enabling different temperatures to be set in each cabin.

"You get a comprehensive package when you buy a Mermaid Marine Air system, " says Rod Boreham of Advance Yacht Systems, which imports the Mermaid Marine Air range of air-conditioning equipment from Florida.

Boreham feels the company's many years experience of the marine market has given it an in depth understanding of the needs of both yards and endusers. As a result, he says rather than offer features such as soft start and time delay as sometimes costly options, Mermaid Marine's air units come with these fitted as standard.

To reduce production lead times and still offer choice, he added, it's useful to make options easy to retrofit so that they could be fitted further down the production line if necessary. For a refit, again, the simpler the installation is; the quicker and easier it can be done. For both situations, there is another spinoff of using the simpler self-contained units, in that it is less likely that something could go wrong and then only be discovered when commissioning.

"This would tend to preclude using chilled water, split-gas and engine driven systems, " said Boreham, "Hence, sales of self-contained systems outnumber these other systems many times over."

Very compact Mermaid says it has focused on keeping its units very compact and claims the M5 is the smallest unit on the market.

This is obviously important if there is only a tiny locker or void under a bunk to fit a unit in.

In addition, customers tell Advance that they do not want to waste large volumes of stowage just for air-con, etc.

The Mermaid range is complemented by what AYS tell us is the first purpose-built dehumidifier for boats on the market. Made from stainless steel cases, it can be built in, or surface mounted and has a low but wide profile.

Climma airconditioning is, they say, extremely versatile;

exceptional at cooling, it also has reverse cycle and electric heating options, making it suitable for Northern European climates as well as the Mediterranean and Caribbean.

Compact versions from 4,500 BTU/hr to 24,000 BTU/hr are available as well as split systems; the split option is especially useful for space saving in accommodation areas and where noise is a critical issue due to the fact that the condensing unit is generally mounted in a remote soundproofed location.

The CWS chilled water systems offer the ultimate system design flexibility and user control. These systems are available from the 12,000 BTU/hr basic module to the XL staged modular versions offering in excess of 400,000 BTU/hr. These systems come into their own in boat lengths of 55ft and upwards and are currently fitted by leading builders such as Royal Huisman and Benetti.

Climma airconditioning is represented in the UK by Fischer Panda UK.