how much is it to replace a oil boiler
1 Mid-efficiency oil boiler replacement cost should be $2,500 to $5,000 installed. 2  Installing a high-efficiency oil boiler might cost $5,000 to $10,000 or more. 3  If replacing an older, low-efficiency boiler with a newer, more efficient model, you may have to install a new chimney liner at a cost of $500 to $2,000.