Can I leave kerosene heater on all night?
Also know, is it safe to run a kerosene heater all night?
Kerosene heaters should not be left unattended, especially when sleeping. A kerosene heater, as any heater that uses organic fuel, can produce dangerously high amounts of soot and carbon monoxide when running out of oxygen. Failure to follow safety precautions could result in asphyxiation or carbon monoxide poisoning.
Similarly, it is asked, is it safe to run a kerosene heater indoors?
As long as you follow the safety guidelines, a kerosene heater can be perfectly safe to use, even indoors. Of course, they can produce carbon monoxide, just as many other appliances can, but as long as you keep your rooms sufficiently ventilated, this shouldn't be a problem.
About your original question, the energy content of kerosene is close to 135,000 btu/gal so you'll get somewhere around 4 hours/gal. 32K BTU is the equivalent of a 2.5 ton heat pump, that would be enough to heat a 1500 sq ft well insulated house.