In a several older properties I have seen an oil heater in the apartment. It looks like a storage heater, has a plug, is manually filled with oil, and it burns it and blows out warm air with a fan.

Has anyone used these? Any tips? Are they OK? How long does a liter of oil last? Are they cheaper than electric?

I have one upstairs in my place, and a log oven downstairs. The oven works nicely.

It looks like the previous owner used 5 litre cans of oil, which he had delivered in small wooden crates!

Hi, is that plug an electric plug? If so, then check out this article: oil-filled radiators vs infrared heaters. It says that oil radiators don't burn the oil, but use oil as a heat reservoir. So never needs refilling. They use electricity to generate heat and are usually 1500Watts powered so thats how much electricity they use / hour. Of course thermostat can save a bit, by turning the heater off when the target temperature met.

In my previous flat we had such a heating system, though it was not manually filled so I'm not sure how much oil was actually used. We did get the pleasure of throwing the lit match in to ignite the oil - very fun. Our ceilings were about 4-5 meters high, which took an electric heater at least a few hours to heat the room. The oil heater though was like opening a door to hell. In a few minutes the whole place was warm. The heat is also much less dry than with an electric heater.