Oil
Today, well over 100 million households in the United States use some sort of fuel or heating oil to keep their homes warm during the winter months. This is despite the growing numbers of people who choose to go with natural gas heating systems. Still, the fact remains that fuel oil is cheaper, in most cases, than using gas, whether it is natural gas or propane.
The furnaces manufactured to burn heating oil operate on similar principles to electric and gas furnaces, yet they are not considered a standard source. The systems for fuel oil heat require more maintenance than standard furnaces in order to run efficiently and cleanly. One reason why more people are using fuel oil is that it can be far cheaper than natural gas and definitely electricity. The Energy Information Agency estimates the cost just under $1,300 annually.
The costs for heating oil can vary depending on where you live in the country, so this limits the usage of such heating system. You should bear this fact in mind if you are considering the purchase of an oil-burning heat system. It will pay to do some research on the costs in your area, before you make such a big purchase.