To find out what the current situation is within this sector we spoke to a number of the major players, the first of which is Dometic, owners of Cruisair, Marineair and Combaria.

Dometic's Trevor Goldsmith told us the company uses a direct expansion modulating system that uses gas as they feel that "chilled water is a low tech option" and has weight implications.

Gas is lighter but, as a few people (mainly those who advocate pressurised water systems) pointed out, finding leaks in gas systems can be a problem.

Dometic has got round this by adding a fluorescing dye to help in locating leaks. Due to the weight issue they feel the chilled water systems are better for bigger boats.

Generally the company feel that this is a good growth market as boats are getting bigger so air con is going into more and more vessels.

The company is developing smaller controls with new systems from Cruisair being beta tested at the moment. One area of development is the socalled soft start to lower the power fluctuations suffered by all users when the systems are switched on.

GenACis sells CLD made in France which has, says director David Melville, been "unsung" in the UK. That was, he added, until GenACis became involved.

The range has been popular on mainland Europe for some time and it's a range that has now been overhauled and is now completely made out of stainless steel.

Melville says GenACis doesn't use split gas as there can be problems when faults occur.

The company only uses a chilled water system with central units and air handlers throughout the boat.

GenACis does a lot of retro fit - including patrol craft - where the system is needed to keep high spec computer systems cool during duties.

Same as auto industry Melville also feels the market is the same as the automotive industry, in that air con is becoming standard in more boats and smaller-sized boats as well. Power is already going this way but sail is now catching up, he says, especially now that easier boat handling systems have encouraged smaller family crews to handle bigger boats that normally have higher spec, including air conditioning. The "floating cottages" as Melville calls them.

The ability to cruise between differing temperature zones and still be comfortable is the approach taken by HFL when developing the Combi Heat Cool, which was shown for the first time anywhere at the Schroders London International Boat Show this year.

By the time this article goes to press the first system will be in place on a boat, said HFL. The idea is to provide three levels of climate control from the same ducting. Level one is air conditioning, level two is reverse air - designed to be ideal for chilly nights when cruising in the Med - but when the water temperature drops below 10infinity, (especially when sailing in more northern locations), the heating system, (or level three), provides warmth via the same delivery ducting.

The diesel heating side of the HFL system requires no shore power or generators to run, making it low cost and with the same ducting being utilised it saves space.

Not wanting to be left out of this move towards air conditioning, Webasto too has joined in. Although new to the market (due to being mostly involved in the heating side of things) the company highlighted that some of the major boatbuilders, especially power craft builders, were selling a large percentage of craft to the Mediterranean and surrounding areas. By supplying only heating, Webasto was losing out. So the company bought into a French air conditioner maker. This move has ensured they can now cover all the bases.

Webasto launched its air con range at London and is now seeing a number of orders being placed.

All orders come via an expanding network of 48 dedicated dealers that are all now being trained on aircon as well as Webasto's heating units. The units offered cover a range from 5,000 to 504,000Btu, which they feel is the widest range currently available.

Total climate control Webasto says it will develop combined heating and aircon to give total climate control as northern water temperature drop below 10infinity in winter makes the reverse cycle, in Webasto's opinion, useless.

James West - sales engineer for marine systems - said SLIBS for them was "a learning curve" and with more experience under their belts they hope that next year's event will prove to be even better.

This year the company will be doing a lot of local events and is already getting a lot of interest from the inland waterways sector.

Although Whispaire doesn't - at the moment - make aircon systems, the company has highlighted an area it feels is in need of attention. They say most units currently available are both heavy and powerhungry, requiring large generators or shore power.

Even then, they say, some pontoons are unable to provide enough power to run units.

It would seem that everyone has highlighted the growth of aircon, including Whispaire, which is working to develop a unit that integrates with their heating range to provide a climate control package.

Director Martin Cookson said the company's aim is to develop a system "that has a lighter power demand and is lighter in weight".

Such a tall order is not going to be available quickly and it's expected that another two years' development will be required before it's ready.

Whispaire is aiming at boat sizes initially below 35ft as the company feels that this area is in most need of a low weight unit, and it's an area currently lacking choice. With more users demanding aircon in the same way as with their cars it's an expanding sector.

Whispaire says its heating units are currently made in Germany and any development in the aircon area is likely to be in collaboration with an existing company working in this sector.

Although most companies are focusing on the aircon sector some, including Eberspacher, have taken a slightly different route, namely demisting for boats. Their philosophy is simple: you would not dream of setting off in your car with misted windows, so why should a boat be any different?

Fan matrix The company has turned its attention to this issue by introducing a 10kW multiple outlet fan matrix unit capable of an output of 360 cubic metres of warm air per hour across the windscreen. The unit has a matrix or core through which hot water/ coolant is passed under the influence of the engine water pump.

An integral fan draws clean air from a locker or outside and passes it through the vanes or channels of the matrix. The resultant warm air is carried to the screens via small flexible pipes.

Due to the screen outlets and duct runs being difficult to fit discreetly after the boat is built, it's more likely to become an original fit product rather than a retro-fit, they say. One spin-off to this, is that the wheelhouse, or helm area is warmed whilst underway.

The majority of companies in this sector have highlighted the need to be involved in the move toward air conditioning being fitted to almost all boats.

Another UK summer like last year and we could see the pace quicken even more.