A Liquid Fuel Used in Homes Is Kerosene

#Flash point: the property that decides it

Flash point is the lowest temperature at which a liquid gives off enough vapour to form an ignitable mixture with air. What burns is always the vapour, never the liquid itself.

Fuel	Flash point	Safe to store at room temperature?
Petrol	~−43 °C	No — always producing ignitable vapour
Kerosene	~38–72 °C	Yes
Diesel	~52–96 °C	Yes, but too viscous for wicks

Petrol in an open container at 20 °C has an ignitable vapour layer above it continuously. Any spark reaches a ready fuel–air mixture. That is why petrol is stored outdoors in sealed containers and never used in domestic appliances.

Kerosene at 20 °C does not produce enough vapour to ignite from a spark. It must be heated first — which is precisely what a wick does, heating a tiny quantity at the flame while the bulk in the tank stays cool and inert.

This is also why putting petrol into a kerosene heater is a fire rather than a fuelling error. The appliance is engineered around a fuel that stays inert at room temperature.

#Why not diesel

Diesel has an even higher flash point, so on safety alone it would seem better. It fails on physics instead: diesel is heavier and more viscous, so a wick cannot draw it up by capillary action at a useful rate. The result is a starved, sooty, weak flame and rapid carbon build-up on the wick.

Wick appliances are matched to a specific viscosity range, and kerosene sits inside it.

#Where kerosene comes from

Kerosene is a petroleum fraction, separated by fractional distillation:

Fraction	Boiling range	Carbon chain
LPG	Below 25 °C	C1–C4
Petrol	40–150 °C	C5–C10
Kerosene	150–250 °C	C10–C16
Diesel	250–350 °C	C15–C20

Sitting between petrol and diesel gives kerosene exactly the balance domestic appliances need: light enough to wick, heavy enough to store safely.

#Domestic uses

Lighting. Hurricane and pressure lamps — for a century the standard household light source in unelectrified areas, and still a common backup.

Cooking. Wick stoves and pressure stoves, widely used where LPG supply is unreliable or unaffordable.

Space heating. Portable radiant and convection heaters. Only heaters explicitly rated for indoor use belong inside, with ventilation and a carbon monoxide alarm — forced-air "torpedo" heaters that burn the same fuel are outdoor equipment.

Grade matters for indoor use: 1-K kerosene limits sulphur to 0.04% by weight, whereas 2-K permits up to 0.30%. Burning 2-K in an unvented indoor appliance releases sulphur dioxide into the room.

#Kerosene against other domestic fuels

Fuel	State	Calorific value (kJ/kg)	Notes
LPG	Gas (liquefied under pressure)	~55,000	Cleanest, needs cylinder
Kerosene	Liquid	~43,000	Wick appliances, stores easily
Natural gas	Gas	~55,000	Needs pipeline connection
Charcoal	Solid	~30,000	Never indoors — severe CO risk
Wood	Solid	~17,000–22,000	Smoky, low calorific value
Cow dung	Solid	~6,000–8,000	Very smoky, very low value

#The LPG ambiguity

Some question sets treat LPG as the domestic liquid fuel because it is stored as a liquid in the cylinder. Standard classification does not: LPG is a gaseous fuel liquefied under pressure for storage, and it arrives at the burner as a gas. Kerosene is a liquid at ordinary temperature and pressure and is burned as a liquid drawn up a wick.

If a question offers both, kerosene is the liquid fuel and LPG is the gaseous one.

If you use one of these appliances, the two guides that matter are kerosene grades, 1-K vs 2-K and are kerosene heaters safe indoors.

#The compact answer

A liquid fuel used in homes is kerosene. It is obtained from petroleum by fractional distillation and is used in lamps, wick stoves and portable heaters. Its calorific value is about 43,000 kJ/kg, and its relatively high flash point makes it safe to store and use in the home, unlike petrol.