Caravan Air Conditioner Sizes and Dimensions Guide
Caravan air conditioners are picked by your van's length and the size of the hole they need in your roof. Most caravans need a power rating between 1.7kW and 3.5kW: a small pop-top under 15ft needs 1.7kW to 2.2kW, a mid-size van (15ft to 18ft) needs 2.2kW to 2.5kW, and a bigger tandem or off-road van (18ft to 21ft) needs 2.5kW to 3.5kW. Rooftop units also need a roof opening of either 360mm or 400mm square, so check that before you buy.
Common caravan air conditioner types and power ratings at a glance:
- Rooftop units: the most common choice, 2.2kW to 3.5kW, fits into a 360mm or 400mm square roof opening, suits most full-height caravans and tourers
- Under-bench units: 1.7kW to 2.5kW, fits inside a bench or wardrobe with just a slim vent on the roof, suits pop-tops, off-road vans and roofs already covered in solar panels
- Portable units: up to 2.0kW, sits on the floor and vents out a window, needs no roof cutting at all
Getting the size right matters more than the brand you pick. Too small, and the unit runs non-stop without ever really cooling the van. Too big, and you're paying for power your van doesn't need.
This guide covers caravan air conditioner sizes by van length, the three main types, and what to check before you buy. Once you know what size and type suits your van, browse the full range in our caravan air conditioners collection.
What size air conditioner matches your caravan
Picking the wrong size is the most common and costly mistake caravan owners make. Here's a simple size guide built around typical Australian caravan lengths.
| Caravan type | Ideal capacity | Best type |
|---|---|---|
| Small camper trailer or pop-top, under 15ft | 1.7kW to 2.2kW | Compact rooftop or under-bench |
| Single-axle caravan, 15ft to 18ft | 2.2kW to 2.5kW | Slimline rooftop |
| Full-height tandem caravan, 18ft to 21ft | 2.5kW to 3.2kW | Standard rooftop |
| Off-road or hybrid van | 2.5kW to 3.5kW | Rugged rooftop or under-bench |
| Fifth wheeler or slide-out van, over 21ft | 3.5kW to 5.0kW total | Dual rooftop or ducted system |
Things like how well insulated your van is, how high the ceiling is, and how many windows you have all change how hard the unit has to work. If you're not sure, pick the higher power rating.
| Caravan type | Power rating needed (relative) |
|---|---|
| Pop-top / under 15ft | |
| Single-axle, 15-18ft | |
| Tandem, 18-21ft | |
| Off-road / hybrid | |
| Fifth wheeler, over 21ft |
Note: the bars show how much more power bigger vans need, not a price or product comparison. Bigger vans need more power simply because there's more air inside to cool.
Air conditioner types compared
There are three main styles of caravan air conditioner. Each one suits a different van and a different budget.
| Type | Power range | Best suited to | Starting price |
|---|---|---|---|
| Rooftop | 2.2kW to 3.5kW | Most full-height caravans and tourers | From $1,295 |
| Under-bench | 1.7kW to 2.5kW | Pop-tops, off-road vans, roofs already covered in solar | From $1,759 |
| Portable | Up to 2.0kW | Budget-conscious or short-term setups | [CONFIRM: no portable model currently listed] |
Rooftop air conditioners
A rooftop unit sits on top of your van, over a hole cut into the roof. Everything is built into the one box, so it doesn't take up any space inside the van.
Options at carac range from the Treeligo 12V Rooftop Universal, a budget-friendly unit from $1,295, up to bigger units like the Dometic FreshJet FJZ7 Pro from $2,245 and the Truma Aventa Comfort from $2,189. The Dometic FreshJet FJZ 7 Lite, from $2,090, runs quieter than most, worth a look if you're a light sleeper.
Under-bench air conditioners
An under-bench unit sits inside the van, usually built into a bench seat or a wardrobe, with just a thin vent showing on the roof. This suits pop-tops and off-road vans where a bulky rooftop box isn't practical, or where the roof space is already covered in solar panels.
The IHider 230V Inverter Underbunk, from $1,759, and the Truma Saphir Reverse Cycle Kit, from $2,169, are both under-bench options currently in the range. Reverse cycle just means the unit can flip into heating mode too, not only cooling, handy on chilly nights.
Portable air conditioners
A portable unit sits on the floor and blows warm air out through a window or door gap using a hose. There's no hole to cut in the roof and nothing permanent to fit.
Will it fit your caravan
This is the question that matters most, and it comes down to your roof and your power supply, not just the power rating.
Rooftop units are built to fit one of two hole sizes, either 360mm square or 400mm square. The 400mm size is more common on European-style vans, while the 360mm size matches the vent opening already used on many Australian caravans.
Before you buy, check three things on your own van:
- Whether your roof already has a vent or hatch opening you can reuse, and which size it is, 360mm or 400mm
- How much weight your roof can carry, since every kilo counts on pop-tops and hybrids, and a heavier unit needs a roof built to hold it
- Your power supply. Caravan parks commonly give you a 10-amp circuit. If you're running off a battery and inverter, or a lighter circuit, look for a soft-start model, which starts up gently instead of drawing a big burst of power that could trip the breaker
A common mistake is ordering a rooftop unit without checking the size of your existing roof opening first. Getting this wrong means extra cutting and resealing work that buying the right size would have avoided.
How to choose the right size
- Measure your caravan's length and match it to the size table above.
- Check your roof opening size, 360mm or 400mm, if you're replacing an old unit or reusing a vent.
- Check your power supply, and look for a soft-start model if you'll run off a battery and inverter or a lighter circuit.
- If your van has extra windows or thin insulation, pick the higher power rating rather than the lower one.
Quick tip: Run your air conditioner monthly, even in winter. This keeps the seals lubricated and the parts in good shape, so it's ready to go when the weather turns.
Maintenance checklist
| Task | How often |
|---|---|
| Clean air filters | Every few weeks in heavy use, especially after dusty conditions |
| Clear exterior vents of leaves and debris | Every trip or as needed |
| Check roof seal and mounting brackets | At least once a year |
| Run the unit even when not needed | Monthly, including winter |
| Book a professional service | Annually, especially for full-time travellers |
Ready to stay cool on the road?
Browse carac's range of rooftop and under-bench air conditioners from Dometic, Truma, Houghton and Cool-J.
Shop caravan air conditionersFrequently asked questions
What size air conditioner do I need for my caravan?
It depends on your van's length. A pop-top under 15ft needs around 1.7kW to 2.2kW, a mid-size van needs 2.2kW to 2.5kW, and a bigger tandem or off-road van needs 2.5kW to 3.5kW.
How does a caravan air conditioner work?
It works the same way as a fridge at home. Warm air from inside is passed over cold coils, the heat gets carried outside and let out, and cooler air is pushed back into the van.
Do I need a rooftop or under-bench unit?
Rooftop units suit most full-height caravans and tourers. Under-bench units suit pop-tops, off-road vans, and roofs already covered in solar panels.
How do I look after a caravan air conditioner?
Clean the filters every few weeks if you use it a lot, clear the outside vents of leaves and dust, check the roof seal once a year, and run the unit every month, even in winter, to keep it in good shape.
Whichever type you pick, the size that matters most is your van's length matched to the right power rating, plus a roof opening that fits without extra cutting. Measure both before you buy.
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Sizes and pricing checked against current carac.com.au product listings, 2026. Roof cutout sizing checked against Australian caravan air conditioner industry sources.