Caravan fridges compared: 3-way and compressor
A 3-way fridge runs on gas, 240V or the car's 12V while the engine runs.
A compressor fridge runs from the van's 12V battery, and some models also take 240V.
Published . 12 min read • Technical Guide
- A 3-way fridge needs vents in the van wall, and it must sit close to level when parked.
- A compressor fridge uses about 30 to 53 amp-hours (Ah) a day in the models on this page.
- Gas work on a 3-way fridge is for a licensed gas fitter.
In this guide
Which type suits your trips?
Thetford makes both types, and it says a 3-way fridge might be the best choice for longer off-grid stays. It says a compressor fridge cools quicker and performs better in hotter environments.
- •Long stays away from power: a 3-way can cool on gas, and the controls still need 12V. Thetford suggests extra batteries and solar panels for long off-grid stays with a compressor fridge.
- •Hot places: Thetford lists its T2000 compressor fridges as class SN-T (10 to 43 degrees) in day mode and SN (10 to 32 degrees) in night mode. Dometic lists its RUA 3-way fridges as class T (tropical), so check the climate class of your model.
- •Sloping camps: Thetford sets 2.5 degrees off level for its N4000 3-way and under 3 degrees for its compressor fridges. Jayco and Evakool say their compressor fridges operate up to 30 degrees off level, and Evakool still recommends a level surface.
- •Noise: Thetford calls its 3-way fridges silent. Its compressor fridges have a quieter night mode.
More models on our site list a compressor fridge than a 3-way (our count, November 2026). That does not show which sells most.
Fridge sizes and power use by model
These are the makers' own figures for models sold in Australia. Ah means amp-hours, the unit a 12V battery is measured in. kWh means kilowatt-hours, the unit on your power bill. g means grams of gas. Each maker tests its own way, so treat comparisons between makers as a rough guide.
3-way fridges
Dometic measures its RUA figures at 32 degrees outside, with 4 degrees average inside the fridge. Thetford gives its N4208 figures at two outside temperatures. The 12V figure is drawn from the car with the engine running, so it does not come from the van's battery.
Dometic RUA 5208X
146 litres, with a 13 litre freezer. Weighs 49 kg.
- Gas: 380 g a day.
- 240V: 3.9 kWh a day.
- 12V, engine running, from the car: 346 Ah a day.
Dometic RUA 6408X
180 litres, with a 46 litre freezer. Weighs 60 kg.
- Gas: 500 g a day.
- 240V: 5.0 kWh a day.
- 12V, engine running, from the car: 400 Ah a day.
Dometic RUA 8408X
216 litres, with a 46 litre freezer. Weighs 64 kg.
- Gas: 500 g a day.
- 240V: 5.8 kWh a day.
- 12V, engine running, from the car: 420 Ah a day.
Thetford N4208
199 litres, with a 42.9 litre freezer. Weighs 53 kg.
- Gas: 300 g a day at 16 degrees, 550 g at 32 degrees.
- 240V: 2.4 kWh a day at 16 degrees, 6.2 kWh at 32 degrees.
- 12V, engine running, from the car: 200 Ah a day at 16 degrees, 517 Ah at 32 degrees.
Compressor fridges
This 12V figure is drawn from the van's battery, day and night. Thetford says actual use depends on the power source, the temperature outside and what is in the fridge. Evakool says use falls as the temperature around the fridge falls. Performance is the mode the RCD returns to after Quiet or Boost.
Dometic RCD 10.5
176 litres, with a 35.7 litre freezer. Weighs 38 kg.
- 12V, Performance mode: 42.4 Ah a day.
Dometic RCD 10.5X
200 litres, with a 40.6 litre freezer. Weighs 39.5 kg.
- 12V, Performance mode: 52.9 Ah a day.
To size a battery and solar for your fridge, read how much solar a caravan needs and powering a caravan at a free camp.
How each type runs on 12V, 240V and gas
3-way fridge
- •240V: from mains power or an inverter. Jayco says a fridge on an inverter uses significantly more battery and can flatten it sooner.
- •Gas: universal LPG (ULPG), never natural gas. Jayco lists gas as the free camping source.
- •12V: only while the car's engine runs. Jayco says it comes through the trailer plug, not from the house battery.
- •The engine signal: to run on 12V while towing, Thetford says a caravan needs a D+ signal from the car. D+ is a wire that shows the engine is running.
- •Wiring: Thetford says 12V performance depends on the thickness and length of the wire, and the install on the car.
- •Auto mode: Dometic's RUA picks 240V first, then 12V, then gas. Thetford's N4000 picks the best source available.
- •After the engine stops: Thetford's N4000 cannot run on gas for 15 minutes, for safety. A Jayco fridge on auto takes about 15 minutes to change from 12V to gas.
- •Starting up: Thetford says to always start and cool down on gas or 240V.
- •Controls: Thetford says the controls need 12V, even when the fridge cools on gas.
- •Altitude: Thetford says lighting problems can occur from about 1000 metres above sea level.
Compressor fridge
- •12V: from the van's battery, parked or towing. Thetford lists 12V as the power source for its T2000 models.
- •Battery protection: Dometic's RCD cuts off at 10.4V and cuts back in at 11.7V.
- •Voltage drop means power lost along the cable. Evakool says most of its customer enquiries are about this, and its compressor needs over 10.9V at the fridge.
- •240V: Dometic's NRX models take 100 to 240V. Evakool's Infinity needs an adaptor of at least 10 amps at 12 volts. Jayco says its compressor fridges run on 240V or 12V.
- •Inverters: Jayco says a fridge on an inverter uses significantly more battery and can flatten it sooner.
Our 12V, 24V and 48V guide covers the van's side of the wiring.
How long to run the fridge before you load it
Thetford N4000 (3-way)
8 hours before food, with the van level
Thetford T2000 (compressor)
4 hours before food
Dometic RUA, RCD and NRX
No food for the first 4 hours
Jayco handbook
At least 24 hours before you leave, on 240V or gas
Loading it
- •Let warm food cool first, and cover liquids (Thetford, Dometic).
- •Leave room for air around the food (Dometic).
- •Put heavy items in the door, the vegetable compartment or on the bottom shelf. Dometic's RUA door takes 10.5 kg in total, with 3 kg per upper rack and 4.5 kg on the bottom rack.
- •The coldest spots are under the fins and at the bottom. Upper door shelves are the warmest (Dometic).
- •Check the cooling again after 4 to 5 hours (Dometic).
Gas while towing, at fuel stops and on ferries
On gas while towing, follow your fridge manual, your van maker and the rules where you travel. Check all three, because makers word it differently.
- •Dometic RUA manual: run on gas while driving only if the vehicle maker permits it, and check the national rules.
- •Dometic RM 2350 manual: while the vehicle is moving, do not run on gas, and turn off the gas bottle.
- •Thetford N4000 manual: gas while driving only with a safety closing device under local regulations.
- •Jayco: keep the cylinder valve closed when travelling.
- •Mars Campers: turn cylinders off before towing, even for short moves in a park.
Fuel stops, garages and ferries
- •Dometic's RUA manual says never to run on gas at petrol stations, in parking garages, on ferries, or on a transport vehicle or tow truck.
- •Its tank stop mode turns gas off for 15 minutes when the ignition goes off. If refuelling takes longer, turn the fridge off or pick another source.
- •Thetford says no gas near petrol stations, and no gas with the vehicle indoors.
- •Jayco says to close the cylinder valve while refuelling.
- •Spirit of Tasmania isolates and tags caravan LPG cylinders, and they stay off for the whole voyage.
If you smell gas
WA's guidance says to turn off the gas at the cylinder and put out any flames. Do not operate electrical switches, and open all doors and windows. Then contact a licensed gas fitter.
How level does a caravan fridge need to be?
Park a 3-way fridge close to level. Dometic says a 3-way fridge parked off level while it runs lets liquid pool in its cooling tubes, which can slow or stop the cooling. Dometic says level is not critical while the van is moving, because the rolling evens out.
Thetford N4000 (3-way)
Performance is guaranteed within 2.5 degrees of level.
Thetford compressor fridges
Thetford says the fridge must be levelled, to under 3 degrees.
Dometic RUA (3-way) and RCD (compressor)
Park level, especially when starting up and filling the fridge.
Jayco compressor fridges
Jayco says they will operate up to 30 degrees out of level.
Evakool Infinity (compressor, chest style)
Evakool recommends a level surface, and says it will operate on angles up to 30 degrees.
Vents, fans, vent covers and shade
A 3-way fridge relies on two vents in the van wall. Thetford says cold air enters the lower vent, passes the cooling unit and leaves hot through the upper vent.
Keep the vents clear. Thetford says too little air can cause incomplete combustion, carbon monoxide and poor cooling. WA's guidance says not to block or restrict openings, flues or vents on installed gas appliances.
Compressor fridges
Thetford says its compressor fridges have ventilation built in, with no need to cut vents in the van wall. Evakool says poor ventilation overheats the compressor and shortens its life, so check your model's manual.
Fans
- •Thetford N4000: fans turn on by themselves as the air around the fridge heats up. If they are not on above 30 degrees, contact a service centre.
- •Thetford ventilator kit: it can be fitted to help cooling in very high temperatures, and it pushes warm air out the upper vent.
- •Dometic RUA: the lower outer fan runs by itself.
Vent covers
- •Thetford N4000: below 6 degrees outside, fit a suitable winter cover at the vents. Take it off once it is above 6 degrees.
- •Thetford N4000: also fit covers in storage, and before you wash the van. Check the vents are clear before you start the fridge again.
- •Dometic RCD: if the compressor is below 0 degrees, close or cover all external grilles.
Shade in hot weather
- •Dometic RUA: keep the fridge out of direct sun, and use sunshades or air conditioning to keep the van cool inside.
- •Dometic RUA and RCD: if it is too hot outside, take off the vent grille for a while. Dometic warns the cooling system at the back gets very hot, so keep clear of hot parts.
- •Dometic RCD: direct sun on the van affects cooling.
What a caravan fridge freezer can do
Use it for food that is already frozen, ice cream and ice cubes. Thetford and Dometic both say their freezer compartments do not suit freezing fresh food.
- •Cold weather: Dometic says that below 10 degrees for a long period, the freezer temperature is not guaranteed.
- •Thetford compressor fridges: raise the cooling level up to 4 to keep the freezer performing if the van falls below 20 degrees inside.
- •Defrosting: Dometic says to defrost when frost passes 3 mm, with the doors open for at least 4 hours.
- •No sharp tools: Dometic says a knife on the frost can make a leak in the cooling system.
- •No fizzy drinks in the freezer (Dometic).
- •Less ice: Thetford suggests fewer and shorter door openings, cooling hot food first and keeping the van dry inside.
Door locks and travel catches
Lock the fridge door before you tow. The storage position that holds the door ajar is not for driving.
- •Thetford N4000: pushing the door closed locks it. The N4175 and N4208 also have a security lock on the bottom of the door.
- •Thetford T2000: on models with a travel lock, secure that too.
- •Dometic RUA: press the door until it clicks, top and bottom.
- •Jayco: pack securely and lock the door, on its towing checklist.
Door locks and fridge thermometers on Amazon
A thermometer shows how cold the fridge is inside. These two links open Amazon searches, and they name no product. If you buy through them, we may earn a commission. Check that a lock fits your fridge door before you buy.
Caravan fridge repairs: what to check and who to call
Check the simple causes in your manual, then call the fridge maker's service agent. Leave gas, flue and electrical parts to a qualified person, as Thetford and Dometic say.
3-way fridge checks
- •No gas: the bottle is empty, the valve is shut or there is air in the line (Thetford, Dometic).
- •No 12V: the engine is not running or a fuse has gone (Thetford, Dometic).
- •Poor cooling: blocked vents, the van is off level, the door is open or there is ice on the fins (Thetford).
- •Three failed gas lighting attempts lock the gas on a Dometic RUA. Its manual gives the reset, and says to call an authorised agent if it repeats.
Compressor fridge checks
- •Compressor not running: a low battery, the 1 minute start delay, overheating or the vehicle fuse (Thetford).
- •Overheated: turn it off for 1 hour and vent the van (Thetford).
- •Cutting out: fuses, a flat battery, loose cables, poor contacts or cable that is too thin (Dometic).
- •A fan or compressor fault goes to an authorised agent (Dometic).
Who to call
- •Dometic: 1800 212 121 for urgent warranty, technical or parts help. Dometic says to contact the retailer if you did not buy from Dometic directly.
- •Thetford: (03) 9358 0700, and its store locator lists service agents. Have the model, serial number and purchase date ready.
- •Evakool: use the Find a Service Agent search on its site.
- •Gas work: a licensed gas fitter in WA, a gas work licence or authorisation in Queensland, and a qualified LP gasfitter in NSW.
- •Yearly check: Thetford says a qualified person should inspect the gas system, burner area and combustion seal each year. WA says to service after long trips or at least annually.
- Dometic: contact
- Thetford: contact
- Thetford: store locator
- Evakool: service agents
- WA: gas appliances in caravans
- Queensland: caravan gas work
- NSW: gas in recreational vehicles
Storing the van? Empty, defrost and clean the fridge, and leave the door ajar (Dometic, Jayco). Close the cylinder valves (Thetford).
Common questions
Can a caravan fridge run on 12V while parked?
A compressor fridge can, from the van's battery. A 3-way fridge should not. Dometic says to run a 3-way on 12V only with the engine running, or the battery soon goes flat.
Can I leave a 3-way fridge on gas while towing?
Only if your fridge manual, your van maker and the rules where you travel allow it. Dometic's RUA manual says to do so only if the vehicle maker permits it. Jayco says to close the cylinder valve when travelling.
Do 3-way fridges work in hot weather?
Yes, within the temperature range of the fridge's climate class, so check your model. Thetford says a compressor fridge performs better in hotter environments, and it says a ventilator kit can be added for very high temperatures.
Do I need a vent fan on a caravan fridge?
It depends on your model. Thetford's N4000 fridges have fans that turn on by themselves as the air around the fridge heats up. Thetford also says a ventilator kit can be added for very high temperatures.
How long will a battery run a compressor fridge?
It depends on the fridge, the heat and the battery. Makers give daily use, from 30 to 52.9 Ah a day in the models on this page. Put your own figures in our power calculator.
Who repairs a caravan fridge?
Use the fridge maker's service agent, and a licensed gas fitter for anything on the gas side. Thetford and Dometic both say gas and electrical work is for qualified people.
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