If you have ever needed to swap a gas bottle for a heater, cooker, barbecue, or camping stove, you have probably wondered which size to buy. The term “calor gas” is widely used as a general name for bottled gas, and the bottles themselves come in a range of sizes, from small cylinders you can carry in one hand to large ones that stay fixed in place. This guide explains the common cylinder sizes, what each one is best suited to, and how to pick the right one for your needs.
What “Calor Gas” Usually Means
In everyday use, “calor gas” is a shorthand term for LPG (liquefied petroleum gas) supplied in a refillable or exchangeable bottle. It is the same type of fuel used for gas hobs, patio heaters, and caravan cookers.
- LPG is a gas stored under pressure so it becomes a liquid inside the cylinder.
- Cylinder size is usually given as the weight of gas inside — for example 5 kg, 13 kg, or 47 kg. It is not the total weight of the bottle.
- Most suppliers offer a small number of standard sizes, which makes swapping empty bottles for full ones simple.
Butane vs Propane: Why It Matters First
Before choosing a size, it helps to know which type of gas you need, because not every size is available in both.
- Butane performs well in mild weather and is commonly used indoors for portable heaters, small cookers, and caravan use. It loses performance in cold conditions, generally below about 10°C.
- Propane keeps working in cold weather and is the usual choice for outdoor use, barbecues, patio heaters, camping, and workshop heating.
- Each type uses a different regulator, so cylinders are not interchangeable without the correct fittings.
As a simple rule: indoor and mild weather calls for butane, while outdoor and cold weather calls for propane. Always follow the appliance instructions for the correct gas type.
Common Gas Cylinder Sizes at a Glance
Exact dimensions vary between suppliers, but the sizes below cover the vast majority of bottles sold for home and leisure use.
Small Cylinders (roughly 3.5 kg to 5 kg)
- Typical size: 3.5 kg butane, 5 kg propane
- Height: around 30–40 cm — light enough to carry comfortably
- Common uses: camping stoves, small portable heaters, single-burner cookers, small gas barbecues, caravan hobs, and fishing or boating trips
- Best for: occasional use and portability
Mid-Size Cylinders (roughly 7 kg to 15 kg)
- Typical sizes: 7 kg butane, 12–13 kg propane, 15 kg butane
- Height: around 50–60 cm — carryable but heavy when full
- Common uses: patio heaters, family barbecues, larger portable indoor heaters, caravans, campervans, small boats, and single-appliance home cooking
- Best for: the most popular all-round size for household and garden use
Patio Gas Cylinders (5 kg and 13 kg)
- A variation of propane supplied with a clip-on fitting designed for quick changes
- Common uses: patio heaters, outdoor fire pits, and gas barbecues
- Best for: anyone who wants a fast, tool-free bottle change outdoors
Large Cylinders (roughly 19 kg to 47 kg)
- Typical sizes: 19 kg propane, 34 kg propane, 47 kg propane
- Height: around 80–130 cm — these should be moved with care or delivered in place
- Common uses: workshop and garage heaters, commercial catering, large outdoor cooking, space heating in off-grid buildings, and appliances that run for long periods
- Best for: high, regular demand where fewer bottle changes are wanted
How Long Does a Cylinder Last?
There is no single answer, because it depends on how much gas the appliance burns. A simple way to estimate is to divide the cylinder weight by the appliance’s hourly gas use.
- A cylinder holding 13 kg of gas, used by an appliance that burns roughly 0.4 kg per hour, will last around 30 hours.
- A small 5 kg cylinder running a low-output camping stove may last many days of short use.
- Heating appliances use far more gas than cooking appliances, so a heater will empty a bottle much faster than a hob.
Most cylinders can be weighed with a luggage scale to check how much gas remains. The empty bottle weight is usually stamped on the collar, and subtracting it from the total weight tells you what is left inside.
Refill or Exchange?
Most bottled gas is sold on an exchange basis. You buy or rent the bottle once, then swap the empty one for a full one and pay only for the gas. This keeps costs lower than buying a new cylinder each time and means bottles are inspected and tested by the supplier. Some suppliers also offer refillable cylinders that you fill yourself at a station.
How to Choose the Right Size
- Check the appliance first. Confirm whether it needs butane or propane and which regulator type it uses.
- Estimate your usage. Frequent use of a heater points to a larger cylinder; occasional camping points to a small one.
- Think about lifting and storage. A 47 kg cylinder is not practical if you need to carry it upstairs or store it in a tight shed.
- Consider how often you want to swap. Bigger cylinders mean fewer trips, but more weight to handle.
- Match the fitting. Buy the correct regulator and hose for the cylinder you choose — they are not universal.
Safety and Storage Basics
- Store cylinders upright and in a well-ventilated place, ideally outdoors or in a purpose-built store.
- Keep bottles away from heat sources, flames, and direct sunlight, and never store them below ground level or in a basement.
- Check hoses and regulators regularly for cracks, and turn the gas off at the cylinder when an appliance is not in use.
- Transport cylinders upright and secured so they cannot roll, with the valve closed.
- If you smell gas, turn off the supply, avoid flames and switches, ventilate the area, and seek professional help.
Conclusion
Choosing a gas cylinder comes down to three things: the type of gas your appliance needs, how much you will use it, and how much weight you can comfortably handle. Small 3.5–5 kg bottles suit camping and occasional use, 7–15 kg bottles are the everyday choice for patios, caravans, and home cooking, and 19–47 kg cylinders are best for heating and heavy, regular demand. Once you know your appliance’s gas type and hourly use, picking a size becomes straightforward. If you want more practical guides on home, garden, and everyday equipment, explore the other articles on this site.