Data Sheet

#18 Winter touring in caravans and motorhomes

#18 #18 Winter touring in caravans and motorhomes
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3: Ventilation and safety


Ventilation and safety

In order to maintain warmth do not look to shut off all forms of ventilation, especially vents provided for safety reasons. The factory installed drop out vents must never be covered - see the Safety first section. The fridge vents can be restricted in winter (temperatures below 8C) with the use of winter vent covers from the fridge manufacturer that restrict the free flow of cooling air but permit unrestricted venting of exhaust gases.

Fridge winter vent covers

Proprietary fridge winter covers reduce cold drafts while maintaining essential ventilation

Where people are located in a confined space, especially where washing and cooking is taking place, you are going to have a large amount of moisture getting into the atmosphere. There is only so much moisture a volume of air can hold and where there are cold surfaces condensation will occur.


This can cause a build-up of damp making the unit unpleasant to use but also cause deterioration to the fabric of the caravan or motorhome. Good ventilation and heating is the best way to avoid condensation becoming a problem. The use of a container of absorbent crystals is not the answer for when the caravan is in use because of the large quantity of moisture generated and the vents. You would simply be trying to take the water out of the ambient air. The bathroom and kitchen are major generators of moist air and the use of an extractor fan in those locations should help.

Units built in accordance with European standards EN1645 and EN1646 will include a set amount of fixed ventilation even when all windows and doors are closed, but this is not sufficient when normal cooking and washing activities are being carried out.

Condensation can be a problem for mattresses as the body gives out moisture when sleeping. This is why most seating and sleeping areas have slatted bases and ventilation boards where they touch the external walls to allow the circulation of air.

Ventilation boards internal

Some caravans and motorhomes have boards to provide ventilation between the wall and seating

In winter when the caravan walls are cold and the underside of the mattress faces an unheated locker there is a danger of condensation and then mould forming on the fabric. To help prevent this, pull the foam away from the walls and lift it up to allow warm air to circulate underneath during the day. Some units have vent boards to keep foam away from the sides of the unit and vents into bed lockers to allow warm air to circulate. If your mattress suffers badly from underside condensation it can be worth using a ventilation mat.



Awnings are a useful way to help keep warm and snug during winter. It is best to use a heavy duty awning. Manufacturers such as Isabella and Dorema produce suitable products classed as winter or all-season awnings. In most cases, winter awnings are porch awnings, but with heavy duty fabrics and strong poles. They also need to have relatively steep pitched roofs to help snow slide off. Additional poles to reinforce the roof can be useful along with strong pegging points and guy ropes to withstand whatever winter weather is encountered. Some manufacturers can supply an awning roof lining to help reduce roof condensation.  For further information on awnings see our Data Sheet number 7.

The awning need only be a small one to enable wet muddy boots and coats to be left out to dry without introducing more moisture than necessary into the caravan or motorhome. As long as it covers the habitation door it should also prevent too much heat loss when entering and exiting. Being small means it is easier to pack up and then easier to be able to spread out on your return home if it had to be packed up while wet.

Never be tempted to use a barbeque in your awning due to the high risk of carbon monoxide poisoning.

Cassette toilets

The materials from which a cassette toilet is manufactured are safe to use in temperatures well below freezing. However, the water and additives needed for use in the toilet are liable to freeze. Thetford toilet waste tank additives and rinse aids have a freezing point similar to that of water and hence should be stored inside if possible. The use of Aqua Kem sachets or similar dry products should eliminate concerns for freezing during storage. To minimise the risk of freezing any of the toilet liquids once diluted and in use, make sure the washroom gets its fair share of heating.

Look after your battery power

If you do not have a mains hook-up you need to conserve your limited battery power. With many sophisticated forms of heating, no electrical power means no heating. The exceptions to this are the Truma S range of gas space heaters that do not require electrical power unless you wish to operate them with a blown-air facility.

A solar panel can help, although overcast winter skies and short winter days can mean the output from a large fixed panel is reduced to a trickle. A good size portable solar panel could be used to supplement the fixed panel and track the sun will be more effective. It is important to ensure you have a good quality battery that is fully charged before your outing. Remember, using a caravan mover to move your caravan will use up a considerable amount of your battery’s reserves, which is unlikely to be topped up enough by the car's alternator. Cold temperatures also slow down the reactions in the battery’s chemistry and result in a reduction in battery capacity.

For longer stays without a hook-up, consider using a generator or second leisure battery. Generators should be chosen for their ability to produce smooth power that will not give rise to spikes in voltage that could damage your electrical system or appliances. Ensure the exhaust from a generator is directed away from the caravan or motorhome (and other units) to avoid the ingress of carbon monoxide and never use inside an enclosed area. If fitting a second battery, ensure it is the same type, capacity and similar age to the existing battery. Also consider that the extra weight will come out of your user payload. Obtain advice regarding the correct wiring and provision of fuses to keep your system safe. Incorrectly wired 12V systems can cause fires.