Are typically used in older houses or where the gas is not available.
the oil furnaces are much less efficient than gas furnace, at least by 20%.
They are not enviromentally friendlsy and there is still risk of oil, as the tank is located inside house.
House Depot recommend to change them to gas furnaces as it runs much more efficient, much less maintenance cost, lower home insuracne, and some other benefits.
housedepot can arrange for getting in touch with gas utility such as enbridge, to bring gas line to your house and convert the oil furnace to high efficient furnace. please call housedpot at 416 822 9030