Diesel heating in caravans and motorhomes – it’s easy, effective and safe

by Collyn Rivers

This is the Webasto Dual-Top water heater unit. The Eberspacher (Dometic) unit is similar. Pic: Webasto.

Carbon monoxide poisoning is your main risk (of heating) in a confined space. Carbon monoxide is colourless and odourless. It forms when a carbon-based substance (coal, LP gas etc) burns without enough air. The (only minor) indications are headache, nausea, fatigue, and then unconsciousness. If you sleep, you may never wake up again. Carbon monoxide is rightly called the ‘silent killer’. It also causes brain damage at minor concentrations.

Your second risk is oxygen deprivation. We need about a half a cubic metre of air an hour. We convert about 4% of that air into carbon dioxide. If you are in a confined space the exhaled carbon dioxide level rises. As a result, the remaining oxygen level falls. It is normally 21%, but symptoms (such as fatigue) set in below 15%. Brain damage consequently occurs shortly after. Oxygen deprivation is serious (or lethal) in poorly ventilated areas. It occurs whether heated or not. See Gas risk in caravans.

Diesel heating for caravans and motorhomes – safety

Use diesel or LP gas heating in caravans and motorhomes to avoid such issues. Both draw air from outside the RV into a tiny furnace that is sealed from the living area. Diesel oil or LP gas is injected and ignited in this furnace. Air to be heated is blown across it and ducted to wherever needed. The ‘burnt’ air expels to the atmosphere. Burning gas is thus totally sealed from the air heated within the vehicle.

The units were first made in the 1930s by Germany’s Eberspacher and later by Webasto. Both are still respected worldwide. The units are similar in many ways. Some parts (such as silencers, calorifiers etc.) are interchangeable. The Snugger, a similar but cheaper unit, is sold by Diesel Heating Australia.
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The Snugger unit. Pic: Diesel Heating Australia.

The company’s Genesis product too is worth considering. So also is the Alde Compact 3010 LP gas unit. This combines space heating and water heating. It also runs from 230 volts ac.

The Genesis II provides space and water heating in one unit. Pic: Diesel Heating Australia.

Truma introduced similar (LP gas) units a few years ago.

The Truma LP gas space heater/ Pic: Truma

The two main types are air heating, and air and water heating. Some are made in various sizes. Use the smallest to heat annexes, camper trailers, small caravans and motorhomes. Use the next size up to heat large RVs.

Air heating

The basic (soup-can size) unit is best floor mounted. A separate tiny electrically-driven pump, hose and filter connects to a separate tank. Alternatively (with motorhomes) to the vehicle’s tank. You can locate the electric control panel wherever convenient.

Water heating

The combined space/water heaters use a furnace unit to heat glycol. This flows through a calorifier heat exchange unit, that also stores heated water for taps and showers. In addition. small fan-powered radiators blow hot air wherever required. The calorifier is also available as a tiny unit that heats water as it is drawn.

The heaters in action

We used a Webasto air heater unit in our OKA in outback Australia. Temperatures there drops quickly after sun-down, often below freezing. Even on its lowest setting, it heated the OKA to 25º C. Expect to use a fifth of a litre of diesel per hour.

We had a Webasto Dual-Top air and water heating unit in our Tvan camper trailer. Used too, around Australia, it worked well and reliably. Its on-line calorifier supplied hot water for cooking and showering. The water is hot within a few minutes.

You must legally, in Australia, add a tempering valve. This valve automatically mixes cold and hot water. It prevents it from exceeding 50º C. Without it, however, the water reaches a scalding 80º C.

If not silenced, the exhaust is noisy outside the vehicle. It bothers nearby campers. You can reduce this by adding the (now standard) exhaust silencer. You can reduce it yet further by adding an inlet silencer. The units are still not totally silent, but unlikely to disturb others.

Here is the Webasto Dual-Top water/space heater in my Tvan. Pic: rvbooks.com.au

Further information on diesel heating for RVs is in Caravan & Motorhome Electrics and The Camper Trailer Book. In addition – Caravan & Motorhome Book. You can use these units to heat rooms in solar-powered houses. My books on solar are Solar That Really Works (for cabins and RVs), also Solar Success (for homes and property systems).

Article: Copyright: RV Books.

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