Oil heater
Oil heaters cost more to run and provide far less heating than gas heaters, they are still used in bedrooms and other small-to-medium-sized enclosed areas. This is because gas heaters, especially without a flue, are not suitable for bedroom use. Gas heaters cannot be used in confined spaces due to the reduced oxygen, and the emissions produced. This leaves electrically powered heaters, such as oil heaters, fan heaters, and heat pumps, as the only alternatives.