As the summers appear to be getting hotter, and more of us are touring on the Continent, life in a motorhome can sometimes feel a bit too warm for comfort.

On the hottest days, opening your ‘van door when you arrive on site can be akin to opening the oven – the heat inside is simply stifling.

Hot motorhomes are not much fun to be inside, and sleeping comfortably in one is nigh-on impossible. You have to keep balancing the relative merits of opening windows and rooflights (mozzie bites) or batterning down the hatches (an unwelcome sauna).

But as well as cooling the interior, air-con is great for allergy sufferers, because most units will clean and dehumidfy the air. Pet owners will appreciate that they can leave animals in comfort if they go out on a hot day.

The best permanent systems are made by Truma, Dometic and Sinclair, but there are portable options, too, like the one from Cool my Camper (CMC).

Choosing a unit

The factors you need to consider are weight, price, power, size, roof position and fitting.


If you want to retain as much payload as possible, remember that an air-con unit can weigh more than 40kg. If you have a passenger on board, you could easily use up 80kg of payload, before you even think about wine and beer! CMC’s portable unit weighs just 19.4kg, minimising the impact on MTPLM.


Good air conditioning is not cheap. The CMC system costs £590, while permanent units start at about £1500. Professional fitting will add £200-plus to the price of the air-con itself.


The power of an air conditioning unit is measured in kW – for example, the compact CMC unit pumps out 0.7kW of cooling power. Roof-mounted systems offer the following: Sinclair, 2.5-3.5kW; Truma, 1.7-2.4kW; Dometic, 1.7-3.2kW.

While more power equals more effective cooling, it also means more weight, cost and power consumption.

Each unit will be designed to cool a particular size of vehicle, so check online to see which is right for you.


The CMC unit is in two parts: one hangs outside the ‘van, the other inside. They are connected by an arrangement of cables and tubes, which can be fed between the seals of a closed window. They are usable on almost any ‘van.

Roof-mounted air-con units must fit in between any rooflights, vents, aerials and satellite dishes you might have in place, so it’s important to measure the roof space carefully!

Another type of permanent unit can be fitted in a locker or storage space, always bearing in mind safe weight distribution.


Roof-mounted systems require a large aperture to slot into. In some cases, they can be a direct replacement for a 400 x 400mm rooflight; otherwise, a bespoke hole will have to be cut.

Check that the positioning won’t affect existing cabling or any of the structural supports. They also need to connect to a power feed from the ‘van’s electrical system.


These four manufacturers make various air-con units from which to select.


Truma’s range provides three Aventa roof-mounted systems and two Saphir units, which can be fitted under a sofa or bed. All are iNet-ready, so can be controlled remotely via an app.

These are high-quality and highly effective. In our experience, they heat just as well as they cool, and can provide a quick heating boost while the Alde warms up.

Truma claims that the Aventa range is the lightest roof-mounted air-con system available, yet it still delivers 1.7kW of fast and effective cooling. Once your target temperature has been achieved, the unit automatically maintains low-level cooling, while drawing a current of just 2.8A. The Aventa is super-quiet and has a sleep function. The award-winning Saphir weighs in at 23.5kg, with up to 2.4kW of cooling. It is quick to install and will cool ‘vans up to 6.5m in length.


Dometic’s latest FreshJet systems are available in various sizes and outputs, suitable for campervans and 6m- or 7m-long motorhomes and caravans.

The FreshJet 1100 is ideal for smaller spaces, such as compact motorhomes – and for smaller budgets, at £1295!

Meanwhile, the mighty FreshJet 3200 is perfect for large vehicles and comes in at around £2400. In between are the 1700, 2000 and 2200 models, so one should be ideal for you.

The exterior units are aerodynamic and stylish. Inside, sleek housings are fitted with smart LED lighting. Dometic also offers the FreshLight 2200 roof unit, which has a built-in rooflight, and the highly effective FreshWell 3000. The latter is installed under a bench or bed, and provides a whopping 2.7kW output.


Sinclair manufactures a range of high-quality, roof-mounted air conditioning units for use in leisure vehicles.

These stylish and substantial systems can be controlled via Wi-Fi and are designed to cool motorhomes and caravans measuring up to 10m in length – in temperatures up to 43°C!

We chose the Sinclair ASV35AS air conditioner for our fitting feature.

This weighs in at a whopping 42.5kg and provides 3.5kW of cooling capacity. It’s a serious piece of kit, with what the company describes as ‘soft-start technology’.

This means that the unit will happily run on 6A current or even DC battery power. It also comes with a handy remote control, LED lighting and a timer, and retails for £2299. This would obviously be significant investment, but one that will provide excellent service.

Cool My Camper

The portable CMC unit runs on 230V, drawing a relatively low current of 1.88A. It weighs in at about 20kg and has a two-year warranty.

CMC offers two fan speeds and four levels of cooling, along with a handy timer. The units are thermostatically controlled, and will automatically switch over to a lower setting when the desired temperature has been achieved.

The literature says this unit will cool a space of 16m³, and online reviews seem to back this up, saying it is very effective for cooling a space before you go to sleep, but perhaps not designed to fully cool the interior of a 6m-long motorhome (approximately 24m³) in the heat of the day. However, pop it into a closed-off bedroom for an hour before bedtime, and it should cope admirably.

Users describe the unit’s noise levels – 46dB at full power inside the vehicle as being ‘similar to a fan’.

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