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What Size Diesel Heater For My Caravan? Easy Size Table

If you’re preparing to embark on a great Australian adventure, skirting its beautiful 34,000-kilometre coastline in a freshly-bought caravan, you’ll want to make the journey as comfortable as possible. Some parts of the country get surprisingly cold, and finding yourself in Melbourne’s frigid winter without a heater for your vehicle could be very unpleasant indeed.

So, what size diesel heater do you need for your caravan? In this article, we provide a simple breakdown of the sizes you need based on the length of your vehicle. Let’s jump in.

What size diesel heater for my caravan?

When you’re trying to heat (or cool) a space, the amount of space is the most important factor to consider. And because most caravans tend to be about 2.2 metres wide, you don’t have to mess around with complicated calculations for cubic volume, but can instead use the vehicle’s length as a general size guide for a diesel heater.

The most common heater sizes you’ll find in Australia are 2kW, 2.2kW, and 5kW. As you’d expect, the longer your caravan, the more powerful the heater will need to be to warm the space effectively.

It’s crucial to get the right-size heater for your vehicle. An undersized heater will struggle to warm the space, and you might find that it’s a little noisy because it’s working so hard. An oversized heater will either work at a very low volume, which can cause carbon to build up and lead to more servicing, or constantly turn itself on and off again as it struggles to regulate the temperature. Like Goldilocks, you’ll need to find a heater that’s just right.

These are the recommended diesel heater sizes based on the length of your caravan.

Diesel heater size based on caravan length

Caravan length

Diesel heater size

Up to 21 feet (most common!)


21 to 24 feet


24 feet +


*This is for Australia. Sub-zero climates will require larger heaters.

The most popular caravan length in Australia is 19 feet, so chances are, you need a 2kW diesel heater. But if your caravan is a flat floor camper, a pop-top, or has a lot of canvas, you should consider going for a 2.2kW heater instead, because the vehicle will lose heat faster.

5kW Diesel Heater

A 5kW heater from RV heater.com

Some websites will show a heater’s output range (e.g. 850kW / 2000kW) rather than a flat number like 2kW or 5kW. If this is the case, you want the second number on the range, which shows the heater’s maximum output.

The weight and dimensions of the heater aren’t important, but you will need to think about where it should be installed in the caravan based on your available space. A bulky heater with the correct kW capacity for your vehicle might have great reviews, but it’s no use if you don’t have the space for it. As you might expect, 5kW heaters are bigger than 2kW heaters.

Diesel heaters can be installed pretty much anywhere in a caravan, although it requires a connection to the fuel tank, so it’s easiest to install it at the front if possible.

2kW or 5kW diesel heater?

If you’re wondering between the two common choices of diesel heater sizes—2kW or 5kW—as mentioned above, it all depends on the length of your caravan. A 2kW heater will work well for a vehicle 21 feet or shorter, and a 5kW heater is best for caravans 24 feet or larger.

Keen to learn more about caravanning? Check out our article on the 5 Caravanning Tips For Grey Nomads. Or take a look at the 5 Best Camping Spots in Southeast Queensland.

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