The best boilers on the market, high-efficiency boilers, typically range from $6,000 to $9,000. A standard gas boiler ranges in price from $2,500 to $5,000, and a standard oil boiler ranges in price from $3,000 to $6,500 on average as of 2015.
There are costs associated a boiler beyond the purchase of the unit itself. For instance, a building permit may be required before a boiler is installed. The fee for this permit ranges from $50 to $300 or more, depending on location. Many contractors include this fee in the cost of installation, but homeowners are advised to understand this fee.
Sometimes the duct work also needs to be replaced or reinstalled. It generally costs from $35 to $55 a foot for materials and labor. This equates to between $1,000 and $5,000 for a typical home. If old ducts contain materials such as asbestos, the asbestos removal must also be taken into consideration.
If a person has an oil fuel tank in the home switching to gas, there is a cost to remove the tank. If the tank is in the basement, it can cost anywhere from $500 to $1,000 on average, but if underground, the cost can be as high as $3,000. There may be discounts available for some homeowners when installing an energy-efficient boiler that can alleviate some of the cost associated with these appliances.