Running a Caravan Air Conditioner from a Generator

Running a Caravan Air Conditioner from a Generator
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There are times of the year and parts of this great country that can experience either extreme heat, or chillingly low temperatures… So, when travelling around Australia in a Caravan/Motorhome, a caravan air conditioner can come in very handy to keep your van nice and comfy inside. When you enjoy the benefits of free camping away from a caravan park and mains power, you’ll likely need to run your caravan air conditioner from a portable generator. So here is what you need to know:

Caravan Air Conditioner

A caravan air conditioner can come in very handy to keep your van either nice and cool when it is hot, or cosy and warm inside during the cooler months.

Even though a caravan air conditioner is a fantastic addition to your vehicle, it will also likely be the most energy consuming appliance on your trip. An average caravan A/C unit consumes between 1000 to 2000 watts when running continuously and when it first starts up can consume between 2000 to 3000 watts to get the compressor going. As a point of reference, compare that to around 100-200 watts for your laptop, 50-100 watts for your fridge, and 40-50 watts for a fan.

We know of some less common examples of campers using their battery packs and a large inverter (say 3000w plus) to run their caravan air conditioner…but this is not very economical and will drain your batteries very quickly! So by far and away, the best way to run your caravan air conditioner in the absence of mains power is via a generator.

What type of Generator?

This part is easy – you’ll need an inverter generator. Inverter generators produce ‘pure sine wave’ power, meaning it is clean power that is suitable to run your sensitive electronic equipment. Because caravan air conditioners have electronic componentry, you need a clean power source which is provided by inverter generators.

Additionally, inverter generators are more fuel efficient than other types of generators as they are able to idle up and down based on the load of the appliance. Lastly, you’ll notice that most inverter generators have a ‘suitcase’ style design, meaning they are enclosed with soundproofing material making them very quiet so you don’t disturb your peaceful campsite!

Caravan Air Conditioner

Inverter Generators produce ‘pure sine wave’ power, meaning they are suitable to run your sensitive electronic equipment. They are also super quiet and very fuel efficient!

What size Generator?

The answer to this is a little less straightforward, but we’ll try to make it easy for you. There’s just a few things you need to consider based on your particular make and model of caravan air conditioner and your particular situation.
Generators are rated by their maximum power output. So, a 2000 watt generator can produce a maximum of 2000 watts at peak, and will run at around 1600 watts continuously. Due to their size and weight, a lot of people want to use a 2000 watt generator, but unfortunately in many cases, this may not be enough power to start a caravan air conditioner.

As mentioned earlier, most caravan air conditioner models will need somewhere between 2000 – 3000 watts to start. So, in order to get the right sized generator, you need to find out how much power your particular caravan air conditioner requires when starting up. Often this is not available on the product data plate or in the product manual (usually only the continuous running power is stated), so it is recommended you contact the manufacturer of your caravan air conditioner and ask them what size generator you would need to comfortably run that model.

If you speak to the likes of Dometic, Air Command, Truma etc. they will typically recommend either a 2400w (2.4kVA) or 2800w (2.8kVA) generator to run their caravan air conditioner models.

Caravan Air Conditioner

Most leading caravan air conditioner manufacturers will recommend a 2.4kVA to 2.8kVA Inverter Generator as the appropriate size to run the majority of air conditioner models.

Other factors to consider in running a caravan air conditioner from a generator?

With all of this in mind, there are a few more things to take into account when looking at a generator to run your caravan air conditioner:

Temperature: As the ambient temperature and/or humidity increases, the power required to start the air conditioner compressor is greater and the power output of a generator decreases. This means unfortunately at the time when you need more power to start the compressor, the generator is actually making less power than it is rated at due to the higher ambient temperature and humidity.

The hotter the ambient air is (the air that is sucked into the engine for combustion) the power output of the engine and generator will decrease. A good rule is to allow a 1.5% decrease in output for every 5 degree C above 25C. So on a 45 C day, a genset will be de-rated by 4 x 1.5 = 6%. Height above sea level will also cause then genset to be de-rated further.

Extension Leads: It is also suggested that a short lead from the generator into the van (no longer than 3-4 meters) is used in very hot conditions, as there is amperage drop over longer leads.
Other appliances: you will also need to bear in mind the load drawn by other appliances running at the same time as your caravan air conditioner: Battery charger, fridge, lights, TV etc. Often we find that customers who are running an air-conditioner on a generator that is only just enough to handle the air con start up requirement, will have troubles if their battery charger is plugged in at the same time for example.

So, overall, these are other considerations when selecting the right generator for your caravan, and highlights that opting for a genset with a bit of extra capacity beyond the peak draw of your air conditioner is a good idea.

Any exceptions to the rule?

Yes. There is one exception to the rule that we know of. In mid 2016, Dometic released the Harrier Inverter Air Conditioner: featuring the first use of an inverter compressor in an RV application. This means the Dometic Harrier Inverter can help eliminate start-up current issues when running from generators or when current supply is restricted. Where most other caravan air conditioners will require more than 2000 watts at start up, the Harrier can comfortably start and run from a 2000 watt generator.

Caravan Air Conditioner

The new Dometic Harrier Inverter Caravan Air Conditioner features the first use of an inverter compressor in an RV application. It will start and run comfortably off a 2000w Inverter Generator.

Recap and Generator Recommendations

In order to get the right generator to run your caravan air conditioner, best practice is to contact the air con manufacturer and find out what is the recommended size generator for your particular make and model of air con. Keep in mind that you may want to have some extra power capacity up your sleeve to account for external environmental factors and for running other smaller appliances.

The Yamaha EF2400iS is the most popular generator to run caravan air conditioners. It will start and run most caravan air conditioner models on the market, and it was awarded the number 1 caravan generator by Caravan & Motorhome on Tour Magazine in their mega caravan generator test.

Other popular models include the Cromtech Outback 2400w, the Yamaha EF2800i, the Yamaha EF3000iSE, the Briggs & Stratton P3000i, and the Dometic TEC29 built-in generator. The latter 4 models being the choice for people running larger air con models and/or wanting a bit more power.

A smaller percentage of caravan owners can get away with a 2000 watt generator. Again, the newly released Harrier Inverter Air Conditioner model runs comfortably from a 2000 watt generator, but while a few other models may do also, issues often arise in hotter temperatures or when you need to run other appliances.

Final Word

When you are choosing a generator for your caravan, it is recommended you opt for a quality brand that has comprehensive warranty coverage along with national service agent and spare parts support. Premium Brands such as Honda, Yamaha, Dometic etc. have hundreds of service agents around the country meaning that if you ever need the genset inspected under warranty, serviced or require spare parts, then you are covered.

Even a select number of budget brand generators, such as Cromtech, have national service agent support. They are made in China, and the premium brand units might be slightly superior in terms of specs, but their price is compelling and you still get national service agent backing.

It is not recommended you choose a cheap no-name generator (often sold on places like eBay) that do not have national service agent support. We repeatedly get stories of these cheap brands not honoring warranty, or when something goes wrong with the generator on the road, then there are long and frustrating delays to the caravan trip as there is no service agent support.

To find out more about generators to run Caravan Air Conditioner units, check out our range HERE.

S Reynolds
Steve Reynolds, Power Product Expert at is a small engine specialist with particular expertise in Generators, Water Pumps, Pressure Washers and other Outdoor Power Equipment products. Outside of work; an avid caravan enthusiast who enjoys time on the road and has gained years of familiarity with Caravan & Camping products also. A passion for power products used for work, home and leisure!
S Reynolds

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  • Meghan Harrison August 15, 2017, 10:31 pm

    Love this post, if noise is a big concern for you, you should check out a quiet enclosure that silences them! See them at They are not only sound proofing but they are also portable. You are able to attach these to back trailers and RVs also.

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