An oil-fired boiler is usually a bit more expensive than a gas-fired boiler. The average price range for a gas-fired boiler is $2,500 to $5,000, and the range for an oil-fired boiler is $3,000 to $6,500 as of 2015.
In addition to the cost of a boiler, other costs may be associated, such as $50 to $300 for a building permit, something needed for all boiler installations. Another cost associated with installing a boiler is the replacement of duct work. This can cost $1,000 to $5,000 for materials and labor in addition to the cost of the boiler. Removal of a fuel tank may also be added into the total cost of a boiler and runs from $500 to $3,000.