Which type of A/C?

[Paul_5041248]

For those with or who have had a/c which is the best type:

The type that goes on the roof (Dometic type) and has this given any stability problems and problems on ferries

The type that is mounted in a 'cupboard' on the floor (Thetford type).

Interested in effectiveness, noise etc.

Many thanks

 

[Lutz]

First of all, you need to be clear in your mind what you expect from air conditioning (where and under what conditions you are going to use it).

The Dometic system is undoubtedly the most powerful and cools down to a lower temperature and quicker than many others but this has its disadvantages, too. It is relatively noisy and can create a cold draught due to its high air output.

The Truma Frostair has, as you say, the advantage of not adding height to the caravan and of keeping the centre of gravity as low as possible. On the other hand, installation inside makes rather more difficult to retrofit to an existing caravan. It is, however, quieter than the Dometic and doesn't create as much of a draught.

Both of the above are compressor systems but there are evaporative systems, too, like the Trav-l-Cool. They are lighter, draw less current and can therefore be run on 12 volts so you don't need a mains supply (for this reason they can be left on while towing) but their performance suffers badly in hot sticky weather with a high relative humidity. For this reason, they only really work well in hot dry climates.

 

[WatsonJohnG]

We had the Trav l Cool for a few years and found the fan very noisy.I fitted an extra switch and resisters to give a slower and quieter fan speed.

We now use a domestic type from a DIY .Its a Cooler/heater/dehumidifier of the non evaporative type.

This is quite good on a very hot day and I often retreat to the caravan to watch the Tour de France etc with the cool air blowing on me as I recline on the caravan seating with a long drink!!

You only have to feel the outlet heat to realise how well its doing its job.It also removes a lot of water vapour at the same time.

The Dometic roof mounted ones are a good way to become unpopular on site because of the noise they make.

Last year on C & CC rally at Aquarius a couple moved from next to a German caravan to avoid the racket from the air con only to have a new rally arrival park next to them fitted with the same Dometic unit.

They were not happy bunnies !!

 

[Paul_5041248]

Thanks for the replies.

Our plans are to retire in the near future. We plan to move to France but also to tour around Europe. As we have a dog felt that at the very least she will require some cooling and, when inside the van, do not want the ice in our drinks melting too quickly.

Your comments on the Dometic unit have been quite helpful and, whilst installation is very easy the disadvantages seem to outweigh the advantages.

Will research the Trav l Cool - will admit had not hard of it before and also take a closer look at the Thetford.

John - what size is your B&Q unit - thinking how to accommodate it in a van.

Many thanks

Paul

 

[WatsonJohnG]

Hi again Paul

The unit we have had for several years is about 12in wide by 15 in deep by 30 1n high.

I will look out the spec and add it later but several similar ones were avaiable in the summer at DIY stores for

 

[WatsonJohnG]

Hi again Paul

The unit we have had for several years is about 12in wide by 15 in deep by 30 1n high.

I will look out the spec and add it later but several similar ones were avaiable in the summer at DIY stores for

 

[ProfJohnL]

Hello Paul,

Having read the replies so far to your question, I think that it is important to highlight some of the differences between the types of units suggested.

a number of replies have suggested a type of air cooler that uses evaporation. These undoubtedly do cool the air, but do so by passing the air over a damp membrane. The latent heat in the air evaporates the water from the membrane which cools the air, but it also adds moisture to the air. Having done a considerable amount of work in this field, I can say that eventually the increased humidity eventually becomes as uncomfortable as the original heat so you are in practice exchanging one form of discomfort for another. The increased air borne moisture eventually condenses out and can lead to the growth of some moulds and fungi. It should also be noted that these are less effective where the natural humidity is already high.

The other type of cooler is a true air conditioner, which cools without adding moisture. These use a refrigeration system with a heat exchanger. They are heavier, noisier and use more power. As has been suggested in other replies they come generally as roof mounted or floor mounted units. The roof mounting requires the roof to be strong enough to carry the weight. The floor mounted ones are slightly quieter.

I have suggested on several occasions previously, that caravanners may wish to consider the AC units sold by DIY stores, which are mobile units. These can be quite effective, plus they are significantly cheaper than the bespoke caravan units, and you can use them at home as well. Thanks to John Watson for his comments on same.

 

[RogerL]

The evaporative type of units are simply coolers and INCREASE the moisture level when the ambient air is probably heavily laden with moisture - not really desirable!

The compressor type of units are true air conditioners which remove excess moisture as well as cooling the air temperature.

Many caravan roofs are UNSUITABLE for a/c installation so check with your vans maker first.

 

[WatsonJohnG]

Too true Roger on another topic it was reported that Bailey (with the much publicised roof that had several people standing on it) had refused to retro fit air con because the roof was not strong enough!!

We meet up with a couple with a Compass and the dividing rail by the fixed bed was coming away from the ceiling.It was no coincidence that the air con unit was directly above and some bowing of the roof was evident.

 

[Guest]

We need to look to our Australian cousins for some good info on these. They have split units with the heavy part at ground level with a grille to the outside. Ducts then take the cool air to other parts of the van. Then again , their climate means they have looked into it far more than us, and of course they can tow caravans 1.5 times a towing vehicles kerbweight legally.

 

[Lutz]

Sounds basically the same as the Truma/Thetford type what you are describing there, Scotch Lad, although the power outputs of Australian units are probably a good deal higher than ours. By the way, if the max. permissible towload is high enough, you can tow 1.5 times the kerbweight of the towing vehicle legally over here, too. I can think of several 4x4's that fall into that category. However, I don't know of any European caravans that are that heavy. The heaviest are 2000kg and all the 4x4's in question have a kerbweight well in excess of 1400kg.

 

[ProfJohnL]

Hi all,

Yes the split system units rather like the commercial ones are available from the likes of B&Q, but I suspect that the overall weight & size will be the problem for UK caravans.

One of the disadvantages of the Truma/Frostair unit is that the condenser coil is mounted inside the box which is inside the caravan, It is essential that exterior air flow over this coil is maximised. In practice this tends to limit the effectiveness of this type of unit because of the casing and the associated air ducting. The Electrolux condenser coil is roof mounted and has better access to exterior air.

It needs an A/C manufacture to look at the concept a bit more. I have suggested that a split system is considered with the condenser coil mounted under the caravan or in the gas bottle locker, and connected by small bore high pressure pipes to the evaporator coil and fan which can be mounted almost anywhere in the caravan. Its not rocket science and similar systems are fitted in many cars.

 

[WatsonJohnG]

That sounds very attractive John

Maybe in five years time it will be as commonplace as air con is on cars now.

Let's hope so

 

[Willy_5041515]

Two points in response to some of the answers (1)You do need to seek the caravan manufacturer's approval before fitting a Dometic unit, otherwise you could easily damage the roof. I have found the Swift Group to be very helpfull on this issue. (2)Yes, they are quite noisy for neighbours and there have been times when we have not used it when we would have liked to for this reason. So, if we anticipate wanting to use it, we try to site the caravan so that the rear vent is pointing away from our neighbours. We also drop round and check with our neighbour if we are in doubt.

Having said this, it has been a "life saver" a few times in France during the summer and we would not wish to be without it.

 

[Guest]

This discussion reminded me of a story that occurred while I was working in Baku, Azerbaijan. There they have 2 types of taxis, yellow ones which tended to be beat up old Renault 12 cars and newer white ones. My wife and some friends were trying to get one to return home on a hot sultry evening and one of their party insisted on getting a new white taxi as 'they have air conditioning' They hailed one, confirmed with the driver he had a/c, and all boarded. The car was hot and sweaty so one of the ladies asked for the a/c to be switched on. The driver wound down his window, flapped his hand and made wooshing noises. He then turned, smiled and said 'look a/c, ok?'. What else can you say?