Something that doesn't make sense to me is that caravans are advertised as having Grade 3 insulation and are suitable for year round use and comfort irrespective of the weather. However, over the past two winters as new caravanners I have found that in windy weather the draft coming from behind the fridge would blow out an octogenarian's birthday cake candles. This has the effect of dropping the temperature in the kitchen dramatically. Another source of drafts - and noise - are the roof vents. Such was the force of the draft at the weekend the pleated blinds buckled! I'm looking at fridge vent covers but can't get my head round the anomaly of well insulated walls and drafts that are equivalent to leaving a window open. I understand ventilation is essential but frankly there seems to be an over-supply of this in windy conditions. Poor design or what?
Winter Caravanning
- Thread starter Notsodaftdanny
- Start date
Hello Danny.
Poor design is I think a fair assessment of the situation, but even if the design were improved to the nth degree there would still be a legal and essential safety requirement for a certain amount of unobstructed ventilation into and out of a caravan.
The inevitable comparison people will make is with their domestic house, but there are two very significant differences which means a touring caravan will always seem like a poor relation.
The first is the construction of a house using bricks and mortar will mean it has a much larger thermal mass meaning that even if drafts do occur to some extent they are warmed as the pass through teh gaps an crevices. Caravan construction has to be light weight, which also means the thermal mass is much much less and the thickness of the structure is less so there is far less chance of warming any drafts as they enter.
The internal space of a caravan is also much smaller than most rooms in a houses, yet we expect to be able to accommodate several people in that small space. Each of those people need to be able to breath and so there is a legal requirement for a certain amount of fixed permanently open ventilation shared between the top and bottom of the caravan. People are naturally going to be closer to these vents so are more likely to feel them than in a house. There also has to be enough ventilation to allow the gas hob and oven to operate, and to allow their products of combustion to exit the living space. This all adds up to a substantial area of ventilation holes in the caravan.
There is a design issue with most caravans. and that is the fridge. The fridge is supposed to be "room sealed" which means there should be no way for fumes from the fridges gas burner to reach the living space. Now teh phrase "room sealed" makes it sound as though there should be a thick hermetic seal around the fridge able to with stand a hurricane, but in fact there are standards that should be adhered to and the quality of the seal is determined by a set of calculations involving differential pressures and surface ares and burner ratings.
In my opinion and others in the industry caravan manufactures fail to install fridges with an adequate room seal, but somehow the authorities do allow them to get away with it.
Fitting winter covers will certainly help, but you could also fit some flame proof foam around the face of fridge to seal it to the cupboards.
Poor design is I think a fair assessment of the situation, but even if the design were improved to the nth degree there would still be a legal and essential safety requirement for a certain amount of unobstructed ventilation into and out of a caravan.
The inevitable comparison people will make is with their domestic house, but there are two very significant differences which means a touring caravan will always seem like a poor relation.
The first is the construction of a house using bricks and mortar will mean it has a much larger thermal mass meaning that even if drafts do occur to some extent they are warmed as the pass through teh gaps an crevices. Caravan construction has to be light weight, which also means the thermal mass is much much less and the thickness of the structure is less so there is far less chance of warming any drafts as they enter.
The internal space of a caravan is also much smaller than most rooms in a houses, yet we expect to be able to accommodate several people in that small space. Each of those people need to be able to breath and so there is a legal requirement for a certain amount of fixed permanently open ventilation shared between the top and bottom of the caravan. People are naturally going to be closer to these vents so are more likely to feel them than in a house. There also has to be enough ventilation to allow the gas hob and oven to operate, and to allow their products of combustion to exit the living space. This all adds up to a substantial area of ventilation holes in the caravan.
There is a design issue with most caravans. and that is the fridge. The fridge is supposed to be "room sealed" which means there should be no way for fumes from the fridges gas burner to reach the living space. Now teh phrase "room sealed" makes it sound as though there should be a thick hermetic seal around the fridge able to with stand a hurricane, but in fact there are standards that should be adhered to and the quality of the seal is determined by a set of calculations involving differential pressures and surface ares and burner ratings.
In my opinion and others in the industry caravan manufactures fail to install fridges with an adequate room seal, but somehow the authorities do allow them to get away with it.
Fitting winter covers will certainly help, but you could also fit some flame proof foam around the face of fridge to seal it to the cupboards.
We have had this problem until we bought Lunar and neither of the two of them have suffered. The last time was simply that the kitchen side panel did not quite reach the floor and the cold air from behind the fridge was leaking into the bed box next to it and out from there. This was in no way the designed in ventilation but rubbish finish, and was solved by blocking up the gap.
I do not condone blocking the necessary vents but I would investigate the source and if like on ours it is just a gap that should not be there block it up or if it is newly bought from a dealer take it back for them to do it. In our case the solution was cost free, so it did not justify the cost of taking it back.
I do not condone blocking the necessary vents but I would investigate the source and if like on ours it is just a gap that should not be there block it up or if it is newly bought from a dealer take it back for them to do it. In our case the solution was cost free, so it did not justify the cost of taking it back.
I've sealed the fridge from the habitation area on both the caravan and the campervan, but left the back of the fridge clear to the vent. It's made a very big difference with very little expense.
Of course you probably couldn't do this to a new van because of future warranty claims.
Of course you probably couldn't do this to a new van because of future warranty claims.
emmerson said:
That will depend on exactly how you have sealed it. If it is a simple self adhesive draft excluder stip. tehn it should not affect warranty in any way.
Thanks for your thoughts all. There is absolutely no seal between the fridge and the cupboard which houses it. In fact, such is the gap around the fridge, I can actually stand in the caravan and look over the top of the fridge and clearly see the outside world through the vent! Regards the roof lights, should they rattle as much in windy conditions? Cheers
On the last caravan that we had we could lie in bed and could hear them rattle with the draught like you say , a little tip for you as for what I did was gently peel back the roof light blind and place a tea towel gently on them then shut them back up and this will weigh them down so they don't rattle about . It worked for us . 
Handy tip to try. Mind you if you spend nearly 25k on a new van they should perhaps throw in a few tea towels...............
I took the fridge out, Prof, and made a baffle plate to go across the top of the fridge. That's why I remarked about warranty. I don't think the manufacturers would like you doing that to a new van!ProfJohnL said:
Keeping in mind that most people are sitting, laying or standing in a caravan, they need little in the way of air, in fact the average person uses 7 liters of air a minute sitting or doing light chores. Which is very little. And while we all breath and sweat not much water vapor is produced. In my opinion it would be easy for the manufacturers to provide adjustable ventilation, with guidance for the user. If you use an electric kettle or hob then most of the current ventilation is excessive.
At a time when we are all encouraged to use less energy, the manufacturers are missing an important trick.
At a time when we are all encouraged to use less energy, the manufacturers are missing an important trick.
On our Coachman 560 there is an air vent of about 1 .1/2 in ( old money) near the water heater under the front seat / bunk, this does give a draught but if we close the roof vent blind over the kitchen , the draught reduces, by maybe 80 %. , but with the onsies on who cares.
When we stayed at the C&CC site on Skye we experienced strong winds which rocked the van and shook the Heki skylights; I opened the Heki blinds to stop them rattling. It seems that a Motorhome Heki is allowed to have a seal around the dome, but not a caravan as to ensure adequate ventilation (Info supplied by Moderator Damian).
Whilst away this January, outside temperatures dipped below freezing, but the inside temperature reached 26c! (Had to turn off the heating and crack a window ) with with that temperature differential I noticed a huge draught coming from under the oven. At first I thought this was coming from the small storage area under the oven, but I noticed a gap under that which must have fixed ventilation. Ultimately I put a towel down in front as a draught excluder.
Even when it was shorts and t-shirt in the lounge, the washroom was still cold though!
Whilst away this January, outside temperatures dipped below freezing, but the inside temperature reached 26c! (Had to turn off the heating and crack a window
) with with that temperature differential I noticed a huge draught coming from under the oven. At first I thought this was coming from the small storage area under the oven, but I noticed a gap under that which must have fixed ventilation. Ultimately I put a towel down in front as a draught excluder.Even when it was shorts and t-shirt in the lounge, the washroom was still cold though!
Perry525 said:
Hello Perry,
In days gone by caravan manufacturers did not provide fixed ventilation, and there were a significant number of cases where injury due to reduced oxygen ensued. Users had the opportunity to use variable ventilations but there were enough instances where serious injury or even death occured to cause the Government to make fixed ventilation mandatory.
Air normally contains 20% oxygen, humans begins to suffer significant problems if the Oxygen percentage drops below 19.5%. we breathe in air with 20% O2 but we breathe out only about 15%. O2
If we were in a closed caravan without ventilation, based on your figures we would consume at least 10,080L of air per day. That is more than half the internal volume of a 5M long caravan! The reduction in the percentage of O2 in the caravan would be in the region of 2.5 to 3.5%! And that's for just 1person!
Add in the oxygen used by the cooker hob and oven, plus the raised Carbon monoxide levels, and you have a seriously deteriorating situation. it would be even worse if there are more people or animals, or it was a smaller caravan.
As for moisture from breathing, an adult can liberate 50 to 100mL of water over night simply by breathing. The use of a kettle or pan will add to the airborne water vapour load, And whenever you burn LPG, roughly for every gm gas consumed you will liberate 1 GM of water vapour in the product of combustion. Obviously room sealed appliances will conduct all the water vapour outside, but none roomseald appliances like hobs & ovens release all their flue products into the living space.
ProfJohnL said:
Prof
I find it a little hard to believe that early caravans were so well sealed that they would cause problems in breathing due to oxygen deficiency. Humans will barely if at all notice any difference if oxygen falls from normal 20.95% to 19%. A bit of breathlessness if exerting themselves. Below 19% the effects of reduced oxygen concentration due start to become noticeable. I’ve been in an environment at 17% and whilst not ccmfortable work continued.
But for humans it’s not the percentage oxygen its the partial pressure that is key. Although for most purposes unless you are in a sealed environment atmospheric concentration will suffice. I was involved in testing a nitrogen drench fire suppression system within a sealed container. The nitrogen came in under pressure to reduce the oxygen concentration below 17% such that fire wouldn’t progress. This reduced the oxygen concentration too but the partial pressure was maintained such that two chaps who failed to heed the warning to exit the compartment survived okay. Albeit somewhat deafened by the noise of the rapid injection of nitrogen into such a large enclosed volume.
The effects of 19-15% concentration of oxygen are progressive and affect individuals differently viz:
“Impaired thinking and attention. Increased pulse and breathing rate. Reduced coordination. Decreased ability to work strenuously. Reduced physical and intellectual performance without awareness.”
Hello Clive,
I do know that the requirements for fixed ventilation shared between high and low level, were introduced because of deaths and serious injuries occuring in caravans. It may not have been oxygen depletion on its own, it was more likely a combination of O2 depletion and increased CO2 and CO due to the burning of gas. This was in the days before it was illegal to have none room sealed heaters and gas lighting.
Caravans of that time were also not well insulated, and many users did try to seal them up to reduce draughts, in doing so the also reduced the air exchange.
Even during the 1990's when I was working for an appliance manufacturer, we were called to do a detailed report on an installation where the owner and his daughter had nearly been killed by CO, it was the result of him not following installation instructions, and blocking the fixed ventilation.
More recently there have been reports of people suffering CO poisening by using a BBQ inside tents and awnings, and these enclosures are far from sir tight, so coming back to discussion point, the fixed ventilation is there for good reason.
I do know that the requirements for fixed ventilation shared between high and low level, were introduced because of deaths and serious injuries occuring in caravans. It may not have been oxygen depletion on its own, it was more likely a combination of O2 depletion and increased CO2 and CO due to the burning of gas. This was in the days before it was illegal to have none room sealed heaters and gas lighting.
Caravans of that time were also not well insulated, and many users did try to seal them up to reduce draughts, in doing so the also reduced the air exchange.
Even during the 1990's when I was working for an appliance manufacturer, we were called to do a detailed report on an installation where the owner and his daughter had nearly been killed by CO, it was the result of him not following installation instructions, and blocking the fixed ventilation.
More recently there have been reports of people suffering CO poisening by using a BBQ inside tents and awnings, and these enclosures are far from sir tight, so coming back to discussion point, the fixed ventilation is there for good reason.
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