Caravan Gas Bottles: Propane or Butane Explained If you have just opened the gas locker on a caravan or motorhome and found a bottle you do not recognise, the question is nearly always the same: propane or butane, and which size fits. Caravan gas bottles come in both, they look similar from a distance, and they behave very differently once the temperature drops. This guide explains the choice the way our depot staff explain it over the counter, including the sizes that actually fit a touring locker, the valve and regulator detail that trips people up, and what to do with an old cylinder you cannot use. Propane or butane: the short answer for caravanners Propane. For year-round touring in the UK, that is the answer almost every time, and the reason is vapour pressure rather than anything to do with brand or price. Liquefied petroleum gas sits in the cylinder as a liquid and has to boil off into vapour before your hob or heater can burn it. Propane keeps doing that at temperatures far below freezing, down to around -40C. Butane gives up at roughly 0C. That is the whole argument in one line. The practical effect catches people out every winter. A half-full butane bottle on a frosty pitch in February will read as empty, the heater will not light, and the owner assumes the cylinder is spent. By mid-morning, once the sun has been on the locker for an hour, the same bottle works perfectly. Nothing was wrong with it. It was simply too cold to make vapour. Butane does carry slightly more energy per kilogram and burns at a gentler rate, which is why it suited the old indoor cabinet heaters and summer-only touring that a lot of caravanners grew up with. If your van only comes off the drive between May and September, and you are running an awning cooker or a cabinet heater, a 7kg butane bottle is still a reasonable choice. Anything else, including winter rallies, early-season weekends and any van with a blown air heater you expect to run overnight, should be on propane. Most modern touring caravans and motorhomes are specified that way from new. Cylinder sizes that actually fit a caravan gas locker The leisure sizes you will see most often from the Flogas range are 3.9kg, 6kg, 11kg and 19kg propane, and 4.5kg, 7kg and 13kg butane. Statics and park homes run 47kg propane. Here is the part online listings skip. Locker geometry beats capacity. Plenty of buyers work out the price per kilogram, decide a 13kg cylinder is better value, and then find the locker door will not shut on it. Measure the internal height of the locker and the width of the door aperture before you choose, not the other way round. A lot of lockers will take two 6kg bottles side by side but will not take one tall 13kg. Two smaller bottles also give you something a single large one cannot: an automatic changeover valve. When the first cylinder runs dry the regulator switches to the second without the heater cutting out at three in the morning, and an indicator tells you which side is empty so you can swap it at your leisure. Weight is worth a thought too. A full 6kg propane cylinder is a manageable lift for one person on a grass pitch. A 19kg or a 47kg is not, and it is not a bottle you want to be manhandling out of a locker in the dark. For statics, that is exactly why a pair of 47kg propane cylinders on a changeover makes sense: the heavy lifting happens on delivery day, not every other week. Regulators, valves and hoses: where caravanners get it wrong Caravans and motorhomes built from 2004 onwards use a single 30mbar bulkhead regulator mounted in the locker, fed from the cylinder by a flexible pigtail hose. That single standard changed what you are actually choosing at the counter. It is no longer the regulator. It is the valve on the bottle and the pigtail that mates to it. Older vans are the ones that give trouble. They often still run separate regulators, 28mbar for butane and 37mbar for propane, screwed or clipped straight onto the cylinder. Swap the bottle type without swapping the matched regulator and you get the classic symptoms: lazy yellow flames, a grill that will not brown anything, a heater that keeps dropping out. Propane cylinders generally use a screw-on POL valve or a clip-on fitting, while butane uses a clip-on or pin type. The valve on the bottle decides the pigtail you need, so tell us which cylinder you are running and we will match the hose rather than guess. Two more points our staff repeat most days: POL fittings have a left-hand thread. They tighten anticlockwise. If it feels like it is fighting you, you are probably turning it the wrong way, and forcing it will damage the seat. Pigtail hoses carry a date stamp and a manufacturer’s replacement interval, commonly five years. Check yours when you service the van, and replace it on the stated interval rather than waiting for it to perish. Never adapt or swap a regulator to make a mismatched bottle fit. Match the cylinder and valve to the appliance instead. And test for leaks with a brush of soapy water around the joint, looking for bubbles, rather than relying on your nose. Any work on the fixed gas system inside the van is a job for an engineer registered with the Gas Safe Register and qualified on LPG leisure vehicles. How long a caravan gas bottle lasts and what it costs to run The honest answer is that it depends almost entirely on whether you are heating or just cooking. Propane holds roughly 13 to 14 kWh of energy per kilogram, so a 6kg cylinder is somewhere around 80 kWh of useful heat. A hob and grill on a summer weekend might draw a couple of kWh a day between you, which is why the same bottle can stretch across several weekends away without a thought. Now run a blown air heater. Typical caravan heaters go up to around 3kW on full output, and on that setting the arithmetic gets uncomfortable quickly: a 6kg bottle would not see out much more than a day of continuous full-rate running. In practice the heater cycles rather than running flat out, so a cold February long weekend is a realistic life for one 6kg propane cylinder, not a fortnight. This is the argument for carrying a second bottle rather than buying one bigger one. Two 6kg cylinders give you a changeover, a spare you can lift, and a shape that fits the locker. One 13kg gives you a lift you will regret and a door that may not close. Static caravans have a different problem altogether. Space heating, hot water and cooking running day after day through the winter is a steady draw-off, and a 13kg bottle forces a weekly exchange cycle nobody enjoys. A pair of 47kg propane cylinders on an automatic changeover handles the load and gets you down to a delivery every few weeks instead. On refilling: UK leisure cylinders are exchanged, not refilled at the roadside. You bring the empty back and swap it for a full one, and the cylinder itself stays the property of the gas company, which is how its inspection and requalification get managed. Underslung refillable tanks on some motorhomes are a different system entirely, filled at an autogas pump, and they are not interchangeable with the bottle in your locker. If you search for a gas bottle refill near me, what you will actually be looking for is a stockist or depot that exchanges your size and valve type. Storing, transporting and changing cylinders safely Cylinders live upright with the valve uppermost, always, in transit and in use. LPG vapour is heavier than air, so a caravan gas locker is built to be vented and to drain to the outside of the vehicle. Keep that drain clear and never block the vents with blankets, chocks or a folded awning. Turn the gas off at the bottle before you travel. Cooking and heating appliances should not be running while the van is in motion, and ferry operators and the Channel Tunnel have their own rules on LPG, usually requiring valves closed and sometimes limiting the number of cylinders carried. Check the operator’s current conditions before you book rather than at the barrier. Do your first cylinder change at home on the drive, in daylight, with the handbook open. Learn the left-hand thread, see where the sealing washer sits, and check it is intact and seated before you tighten. A missing or split washer is a slow leak you will not smell from inside the van. Where not to store a spare: car boots, under beds, inside the caravan itself, and sealed garages with no ventilation. A spare bottle belongs in the vented locker or outside in a secure, well-ventilated spot. Liquid Gas UK, the trade association for the LPG industry, publishes guidance on safe cylinder storage and handling if you want the detail in full. Buying, exchanging and returning caravan gas bottles in the North of England Innergy is a Flogas distributor with depots at Leeds, Dewsbury, Knottingley, Goole, York and Manchester, so you can collect from the counter or have cylinders delivered within our set areas across Yorkshire and the North West. Onsite parking is available at our depots and a colleague will help you load, which matters more than you think once you are into 19kg and 47kg sizes. Bring the empty and, if you can, a photo of the locker with the regulator and pigtail in shot. Our staff will match the cylinder size and valve type to your appliance rather than guessing from the weight alone, and if a 13kg will not physically fit your locker we will tell you before you buy it, not after. You can see the full range of domestic and leisure bottled gas on our gas for home pages, and the wider innergy bottled gas and equipment range if you need regulators, hoses or accessories at the same time. Second-hand caravans are a common source of a problem we see weekly. The van comes with a legacy cylinder in the locker, often an unfamiliar size or an obsolete valve, and the new owner cannot exchange it and will not use it. Do not leave it to corrode behind the lawnmower. Old or unwanted cylinders can be collected and returned through us, which is both the safe route and the correct one, because the cylinder belongs to a gas company and still contains residual gas. Also, if you are supplying a site, a club rally or a holiday park rather than a single van, we run scheduled deliveries for account customers so the cylinders simply turn up, with no need to pick up the phone each time. Even better, we can usually sort a last-minute delivery if you run short mid-season. The same depots and the same drivers supply dispense gas to pubs and bars across the region, and if that is your trade too, our guide to what pubs pay for beer gas covers the cost side of that in detail. If you want pricing for an account, a site supply or a regular delivery of caravan gas bottles, request a quote and we will come back to you. For a single bottle, call or visit your nearest depot and tell us what is in the locker. Frequently Asked Questions Can I use butane in my caravan in winter? Not reliably. Butane stops vaporising at around 0C, so on a frosty pitch the bottle behaves as if it is empty even when there is liquid gas inside it. Propane keeps vaporising to around -40C, which is why it is the sensible choice for any touring outside high summer. If your van is on a seasonal pitch and only used in warm weather, butane is fine. What size caravan gas bottles fit a standard touring locker? Most touring lockers are designed around 3.9kg or 6kg propane, often two side by side, with 11kg fitting some larger lockers. Measure the internal height and the door aperture before you choose, because a 13kg cylinder frequently will not fit even when the weight allowance is there. Statics and park homes normally run 47kg propane instead. Do I need a different regulator for propane and butane? If your caravan or motorhome was built from 2004 onwards it has a single 30mbar bulkhead regulator that handles both, and what changes between gases is the pigtail hose and the connection to the cylinder valve. Older vans with cylinder-mounted regulators do need a different one, 28mbar for butane and 37mbar for propane, and mixing them up is a common cause of yellow flames and sluggish burners. How long does a 6kg propane bottle last in a caravan? Cooking only on summer weekends, a 6kg cylinder can last several trips. Running a blown air heater through cold nights, the same bottle can be gone inside a long winter weekend, because the heater draws far more gas than the hob ever will. Carrying a second 6kg bottle on a changeover is more practical than moving up to one large cylinder. How do I return an old or unwanted gas cylinder? Bring it to one of our depots at Leeds, Dewsbury, Knottingley, Goole, York or Manchester, or ask about collection if it is too heavy to move. Do not put a cylinder in household waste or leave it at a tip, and do not store it in a sealed garage, because it will still hold residual gas. Give us the size and the markings on the shoulder and we will tell you what can be taken back.