Gas is the cheaper fuel choice. Gas is cheaper by BTU's and the price does not rise on speculation. Oil spikes with season trends and projected demand. That increase is passed on to the consumer the same day.
Depends who you ask - the oil comapny or the gas company. You have to also check to make sure that there are gas lines in the street to service your house. There are also many other factors to consider - short term as well as long term. Good luck in your search for the truth and what is best for you.
Oil costs may be slightly higher, however do consider researching the topic and take a look at current pricing by contacting oil companies and National Grid.
Because oil prices have taken a spike this past year, it costs more to heat a house with oil than it does with gas. There are several incentives offered by national grid this year to reduce your net cost to make the conversion should you wish to plan for it in the near future. If you have any other questions, please contact me at 516 320 3345. Good luck in your search!