The Winter 2017-18 EIA Fuels report was released today and as usual it is a US average report. This means that it shows that if you heat with electricity, your cost isn’t that much (due to homes being in the South that don’t have many degree days) or that natural gas likewise is less expensive on average – again because it is not as cold in most places that heat with natural gas so the average looks lower. In Maine, where we have some of the coldest weather, naturally we need more fuel to heat our homes, thus the total bill is higher. Which is precisely why it appears that heating with oil is more expensive than heating with electricity (southern average usage) or natural gas (US general average) heating oil – northeast average (coldest). https://www.eia.gov/outlooks/steo/report/winterfuels.cfm
As to price comparisons: Average heating oil and winter natural gas rates in Maine are around $2.20 gallon or $15.00 per million Btu. Maine Heating oil prices have mostly been the lowest in the country for many years.
In sum, Maine has lower per unit prices for heating oil than the rest of the country, but uses more per capita due to the cold and thus the EIA, when using averages in teh Winter Fuels report seems to indicate that using oil is the most expensive heating fuel. It is not. Today in Maine, oil, natural gas and wood are about equal in price. The outlook for winter price comparisions is about the same.