LPG in cold weather: why the flame drops in winter and what to do safely
Every winter people in Murree, Gilgit, Skardu and on cold nights in Islamabad think their cylinder is empty when it is not. The reason is the gas mix Pakistan uses. Here is the science in plain words and the safe fixes.
Quick answer
Pakistan's LPG is about 40% propane and 60% butane (the mix OGRA prices it on). Butane hardly turns into gas below about 0 °C, so in the cold the pressure drops and the flame weakens even with gas still inside. Never heat the cylinder. Shelter it, use a bigger cylinder or two joined together, and spread the load.
The science in one table
| Propane | Butane | |
|---|---|---|
| Share of Pakistan's LPG (OGRA price basis) | About 40% | About 60% |
| Turns from liquid to gas down to | About −42 °C | About −0.5 °C |
| In winter | Keeps working | Slows down near freezing |
More detail: propane vs butane and LPG composition and properties.
Signs it is the cold, not an empty cylinder
- The flame is weak in the early morning and better in the afternoon
- The cylinder feels icy or has frost on its lower half
- It weighs well above its tare weight (TW) on a scale
- The flame dies when the geyser or heater runs at the same time as the stove
Safe fixes
- Keep the cylinder upright, outdoors or in a ventilated, sheltered spot out of the wind; let it get daytime sun
- Use a larger cylinder (15 kg or 45.4 kg) or two cylinders on a changeover so each one does less work
- Do not run a geyser, heater and cooking together from one 11.8 kg cylinder
- Never use a flame, heater, hot water or hot cloth on a cylinder, and never bring it into a closed room to warm it
- Check the hose: cold makes old rubber stiff and cracked
Weigh to see how much gas is left: LPG cylinder weight. For homes using gas heaters, read LPG heaters: safe use.
Frequently asked questions
Why does my LPG cylinder seem to finish early in winter?
Usually it has not finished. Pakistan's LPG is about 60% butane, and butane barely turns into gas near 0 °C, so the flame weakens while liquid is still inside. Weigh the cylinder: if it is well above its tare weight, gas is left.
Is it safe to warm an LPG cylinder?
Never heat a cylinder with a flame, heater, hot water or by putting it near a stove. Keep it upright in a sheltered, ventilated place out of the wind, and in the sun in the daytime if possible.
What is LPG made of in Pakistan?
OGRA's price notification is built on a mix of 40% propane and 60% butane. Propane stays a gas down to about −42 °C; butane only to about −0.5 °C.
Why does my cylinder get frost on it?
Turning liquid into gas takes heat from the cylinder. With a heavy draw (a geyser or heater plus cooking) the cylinder cools until moisture freezes on the outside. It is a sign you are drawing more gas than the cylinder can supply comfortably.
How do people in Murree or Gilgit keep gas flowing in winter?
They use a larger cylinder, or two cylinders joined through a changeover so the load is shared, keep cylinders sheltered, and do not run a geyser, heater and cooking all at once from one small cylinder.
Can I order LPG at night in winter?
In Islamabad and Rawalpindi we take orders 24/7. In Murree and other cities we pass the order to a partner and confirm the time before you agree.