I suppose to be accurate, we all use a central heating system to heat our 'vans-one source that spreads by convection and radiation. But here I mean the commonly used term to signify a central source and distribution via water filled radiators. Electrolux offer such a scheme and the Editor and I attended a full demonstration and a useful discussion with the Swedish inventor. The GP 250 was operating in two caravans and there was no doubt that they were well heated - I spotted our Editor removing his jacket!

The problem is to find a place to site the four radiators. There is usually room for one at the rear and another right up front. Electrolux site the other two at the back of the bedding lockers. Air enters through the front at ground level and passes under a false floor to the locker and is ducted up to emerge behind the backrest.

As will be seen the heater is built into the side of the wardrobe. Figure 1 shows how this works. Air for combustion enters through the floor 1 and products of combustion are released into the open air 2. The heat is controlled by a thermostat 3 and this boils the 50/50 water-antifreeze mixture at 5 and the "head" is above this. The almost boiling mixture now goes round to the radiators, gives up its heat and returns to the heater.

To keep the caravan fresh, air enters from under the floor 7, passes over the outside of the boiler and emerges as warm fresh air into the 'van via a grill 8. But if fresh air is to come in there must be a way out for the stale air and this should be through the roof. I have reported in the past the excellent results I have had using the Electrolux Ventilator.