Caravan aircon experience

[fkeates]

Hi
I (used to and still hoping!) go to France a lot with the caravan, and looking for advice & experience from people who have had aircons installed in their caravan, please?
I'm interested in the roof mounted types and would like to know if they're effective, noisy, weight issues, and what power consumption they need?
I currently take a portable one but this is noisy and takes up space.
I'm not interest in air coolers or fans, as these are ineffective in the higher temps of the med ☀️☀️☀️☀️
Thanks

 

[Buckman]

I tried to reply to your question on other thread, but it has been closed. regarding the Truma Comfort with heating on maximum is 3.7amps and maximum cooling is 4amp. Similar to our Dometic which we were able to use on sites in Spain that only had a 6amp supply.

Power supply
230 V – 240 V , 50 Hz
Power consumption
Cooling: 4.2 A
Heating: 3.7 A
Start-up current
28 A (150 ms)
Cooling power
2.4 kW
Heating power
1.7 kW (heat pump)
Air volume flow
max. 400 m³/h
Usage limits
+4 °C to 40 °C
Maximum angle during operation
8 %
Weight
33 kg plus installation materials
Dimensions (W x H x D)
External: 660 x 248 x 1008 mm
Internal: 523 x 46 x 670 mm
Refrigerant
R 407C / 0.67 kg
Contains fluorinated greenhouse gases covered by the Kyoto Protocol. Hermetically sealed.
Global Warming Potential (GWP)
1774
CO2 equivalent
1188.6 kg

 

[ProfJohnL]

One of the problems with AC in caravans is managing performance expectations. Most cars now have AC and if you expect to get similar cooling performance in a caravan you will be disappointed.

The biggest restriction in a caravan is the availability of electrical power to run it, In a caravan at best you have a 16A supply which if it were all used for the AC would give you a power input of 3.6kW. That would leave nothing for any other electrical appliances. So most caravan AC manufacturers limit the maximum input power to 2kW or less and also have reduced settings.

Caravan AC units utilise a compressor based system, and will usually have a coefficient of performance (COP) of around 2.5 This means for every Watt of input energy it will move 2.5 Watts heat. This is good an why heat pump technology has some great potential forspace heating and cooling.

Buckmans unit has a 4A consumption that is only 920W. With a COP of 2.5 that gives a total cooling capacity of only 2.4kW This is great, but in reality it's not a lot of cooling, and this is where expectations are often not met.

Not many Brits have AC at home, so they have a limited experience most often of how a car system performs. In a car the AC unit is usually driven by a belt from the engine. It will of course depend on the make and model, but its not uncommon to find the AC will use 5 to 8 Horse power (= 8 to 11kW) of power to drive it. Again applying the COP of 2.5 means the system in a car may be able to provide between 20kW to 27kW of cooling. That almost 10 times as much as the caravan unit. - though to be fair the AC does not run continuously in most cars it is thermostatically controlled and may run for about 50% of the time , but thats still 10 to 14kW.

Now consider the volume inside a car the AC is expected to cool. IN some SUV's you might have 4cu meters. so that gives power to volume ratio of 2.5 to 3.5 kW/m3.

In a 4.5m long caravan you will have a volume of about 16.2m3 and a cooling capacity of at best 2.4kW that's only 0.15kW/m3 or 6% or less of the capability of the cars system!

However the job in a caravan is slightly differnt, The ratio of surface area (both wall and glass) to volume is better than a car, and teh level of insulation is also probably better so the need for an AC may be reduced compared to a car. And using the caravan AC you may find you want to selectively cool some areas more than others, and it has to be said that many caravaners do find AC works well enough for them and improves comfort in hot weather.

Just don't expect ice cubes to be frozen at the AC's nozzels.

 

[Buckman]

We are very happy with our air con as it works efficiently and keeps the caravan cool. The dogs enjoy it as it keeps them cool. An air con in the summer months probably uses less power than blown air or ALDE heating in the winter.
Not sure why any one would want to be frozen in their caravan as our air con is set to 20C which is comfortable for all of us when we return to the caravan after a day out. On automatic it cuts in and out to regulate the temperature inside the caravan. Also a caravan is better insulated than a car so cooling is more effective.
Previously at home we had to have air con in lounge area, another in the dining room and air cons in the bedrooms. Kept the house cool as outside would be well over 30C and sometimes hitting 35C in the shade.
In those days cars with air con were very rare and it had to have a least a 3litre engine for air con to work properly. My Datsun 1600 that I got many years later would almost come to a standstill when you switched on the air con.

 

[otherclive]

We are very happy with our air con as it works efficiently and keeps the caravan cool. The dogs enjoy it as it keeps them cool. An air con in the summer months probably uses less power than blown air or ALDE heating in the winter.
Not sure why any one would want to be frozen in their caravan as our air con is set to 20C which is comfortable for all of us when we return to the caravan after a day out. On automatic it cuts in and out to regulate the temperature inside the caravan. Also a caravan is better insulated than a car so cooling is more effective.
Previously at home we had to have air con in lounge area, another in the dining room and air cons in the bedrooms. Kept the house cool as outside would be well over 30C and sometimes hitting 35C in the shade.
In those days cars with air con were very rare and it had to have a least a 3litre engine for air con to work properly. My Datsun 1600 that I got many years later would almost come to a standstill when you switched on the air con.

Do you leave your aircon running when you are out or is it efficient enough to start reducing the temperature when you arrive back at the caravan?

 

[Buckman]

Do you leave your aircon running when you are out or is it efficient enough to start reducing the temperature when you arrive back at the caravan?

As it is thermostatically controlled we leave it running when out and about. If you switch it off and then switch on when you come back is a bit pointless as the caravan may be sweltering hot and it will take a while to cool down like with heating taking awhile to warm up the caravan.
Also remember that if it has been off all day and then switched on when the inside of the caravan is boiling hot, it may draw even more power then if it had been running all day. As said we find 20C to be the ideal temperature for us.

 

[ProfJohnL]

Do check with the caravan dealer that the roof is strong enough to carry the AC unit.

 

[Buckman]

Do check with the caravan dealer that the roof is strong enough to carry the AC unit.

Actually that is a very important point as many later model Lunar twin axles could not have a roof mounted air con. I do not know about other brands. Unfortunately the OP has not stated their brand of caravan.

 

[fkeates]

Roof strength is definitely a limiting factor and something I've got to check out (but don't think it'll be an issue as a/c was an optional extra for my van when new)...

I'm interested whether they actually perform as well as the manufacturers claim and what peoples experience of the different makes and models is? Chatter on social media during the really hot spell a few weeks ago seemed to suggest they were a godsend (as backed up by Buckman's comments)! Not looking for freezing cold, just cooler than 25-30+C.

Also, what the noise level is like as it's not something you can judge at the camping shows. I'm worried about disturbing other campers as i know noise can travel especially at night. (my portable unit is quite noisy)

 

[Buckman]

We previously had the Dometic Freshjet 2200 for nearly 6 years which was also very good at cooling the caravan however poor design meant we had constant issues with it mainly with water condensation a known issue which they were not able to resolve. We transferred it to three different caravans. Eventually last year it gave up the ghost.
We then had the Truma installed as we would not be withouit an air con. The Truma is slow to change modes. The Dometic was instant. The diffuser on the Truma gives you more options for air circulation. Otherwise not much difference between the two. Below is for the 2015 Freshjet model;

Power consumption cooling was 4.1a
Heating mode 5.1a
Max area cooled 25 square metres

Noise level outside is minimal when on maximum cooling. Normal cooling you would not know it is on. This applies to both. However internally when on cooling it can be noisy. At night we have ours on fan only mode for air circulation.

 

[fkeates]

We previously had the Dometic Freshjet 2200 for nearly 6 years which was also very good at cooling the caravan however poor design meant we had constant issues with it mainly with water condensation a known issue which they were not able to resolve. We transferred it to three different caravans. Eventually last year it gave up the ghost.
We then had the Truma installed as we would not be withouit an air con. The Truma is slow to change modes. The Dometic was instant. The diffuser on the Truma gives you more options for air circulation. Otherwise not much difference between the two. Below is for the 2015 Freshjet model;

Power consumption cooling was 4.1a
Heating mode 5.1a
Max area cooled 25 square metres

Noise level outside is minimal when on maximum cooling. Normal cooling you would not know it is on. This applies to both. However internally when on cooling it can be noisy. At night we have ours on fan only mode for air circulation.

Thanks - good info 👍

 

[ProfJohnL]

I have been on sights where the noise of close by AC units was definitely disenabled at night when windows were open, but the same can also be said of some water pumps and heating systems.

It's largely down to the individuals noise sensitivity which can vary wildly.

 

[Buckman]

I have been on sights where the noise of close by AC units was definitely disenabled at night when windows were open, but the same can also be said of some water pumps and heating systems.

It's largely down to the individuals noise sensitivity which can vary wildly.

That would have been a long time ago in the past. Today even on full cooling blast you can hardly hear the air con during the day and at night when sound carries further the air con is a lot quieter than the TV in the caravan next door.
As said we have never used the air con after 10pm as by that time the caravan has cooled down enough for a comfortable sleep.
Strangely neither Dometic or Truma give the db level of the air con?

 

[WinifredHobbs]

Our air conditioner is not mounted on the roof but the back wall. Fluid is constantly dripping down behind us and leaving traces on the road. I'm not very happy with this arrangement, so I'm thinking of installing a new air conditioner on the caravan's roof and fixing the problem of leaks. Maybe it's the old condenser. Either way, the air is perfectly cool now. I took the caravan to clearwater air conditioning repair a month ago, and they fixed the AC, but it's so old, I should get a new one. What do you think about it?

 

[Buckman]

Our air conditioner is not mounted on the roof but the back wall.

Just a guess you are not from the UK?