Diesel heating in caravans and motor homes is by far the safest approach because it hugely reduces the risk of carbon monoxide poisoning. On a practical level diesel heating in caravans and motor homes is relatively affordable and easy to self-install. Fuel is available almost everywhere and is safe and easy to store.
The main risk of heating in any confined space is carbon monoxide poisoning. Carbon monoxide is a colourless and odourless gas (slightly lighter than air) formed whenever any carbon-based substance (which is most substances) is burned without enough air – or if burning is only partly complete. There are only minor indications: headache, nausea, fatigue – and then unconsciousness. If you were asleep, you may never wake up again. Carbon monoxide is rightly called the ‘silent killer’. It is now known to have serious effects at much
The second risk is oxygen deprivation. We breath in about a half a cubic metre of air an hour and convert about 4% of that into carbon dioxide.The exhaled carbon dioxide level rises and the available oxygen level falls. The latter is normally about 21% but may fall to 15% before symptoms (such as fatigue) set in. Oxygen deprivation can be serious (even lethal) in an unventilated space – heated or otherwise. See my (fully referenced) article on the above ( Gas risk in caravans ).
Safe RV heating
Diesel heating in caravans and motor homes avoids the above problems by drawing air from outside the RV into a tiny sealed furnace (located such that it is sealed from the main RV area). Diesel oil is injected and ignited in this furnace and ‘burnt’ air is expelled to atmosphere. The air to be heated is blown across the hot outer skin of the furnace and ducted to wherever needed. The burning gas is thus totally sealed from the air that is heated within the vehicle.
Heaters such as these have been made since the 1930s by Germany’s Eberspacher company and later by Webasto. Both brands are highly respected in Europe, the USA and Canada, but were not widely promoted in Australia until 2007 or so. A similar unit but cheaper unit is available from Diesel Heating Australia. Truma introduced similar units a few years ago – one of which operates on LP gas.
Both Eberspacher and Webasto have long been in the same small German town and some staff move from one to the other. Possibly as a result the products are so similar that a few parts are interchangeable. There are two main types – air heating, and air and water heating with both made in two sizes. The smallest produce ample heat for annexes, camper trailers, small/medium sized boats, caravans and motor homes. The next size up will readily heat a large caravan, motor home or coach conversion.
The basic (soup can size) air heating unit is best floor mounted as both the intake and exhaust are on its underside. A separate tiny electrically-driven pump, hose and filter may be connected to a separate diesel tank – or can be tapped into the main vehicle tank. A small electric control panel may be mounted wherever convenient within the vehicle. The hot air is vented to wherever desired via approximately 50 mm diameter flexible hose.
The combined space/water heaters have a furnace unit that heats glycol that then flows through a calorifier heat exchange unit. This in turn heats water that feeds taps and showers, plus small radiators through which air is feed fan-blown radiators throughout the vehicle. The calorifier is available as a storage tank that holds xx litres of hot water – or as a tiny on-line unit that heats water as it is drawn.
The heaters in action
I used a Webasto air heater unit in a previously owned OKA in much of outback Australia. Temperatures there drop quickly after sun down and often to below freezing. Even on its lowest heat setting, the heater kept the OKA’s interior at a comfortable (for us) 25 degrees C whilst using about a fifth of a litre of diesel an hour.
A Webasto Dual-Top air and water heating unit was installed in a later-owned TVan camper trailer and used all around Australia. This too worked very well, supplying ample hot water for cooking and showering after five or so minutes of being turned on. It is necessary, and legally required in Australia, to add a tempering valve that mixes cold and hot water, as it is otherwise at a scalding 80 degrees C. The water heating radiator was more than adequate for heating the trailer’s interior and annexe.
Unsilenced, the exhaust is intrusive outside the vehicle and may bother neighbouring campers at night. This is reduced considerably by the now standard exhaust silencer and further still by the (then optional, but necessary) inlet silencer.
The Eberspacher brand is sold in Australia as Dometic, the Webasto by Kimberley Kamper. Owners of the units say that they are very similar in performance.
The Webasto Dual-Top water/space heater in the author’s Tvan. Pic: caravanandmotorhomebooks.com.
Further information regarding associated matters can be found in the author’s associated books, particularly Caravan & Motorhome Electrics, the Campervan & Motorhome Book, and the now second edition The Camper Trailer Book.
Article: Copyright: caravanandmotorhomebooks.com