A standard gas boiler insulation ranges in price from $2,500 to $5,000, and a standard oil boiler ranges in price from $3,000 to $6,500. When the cost of the boiler is added in, the average is $5,150.
If a person chooses a high-efficiency boiler, the average price is $6,000 to $9,000, but when the price of the boiler is added to that cost, it may rise to over $11,000. A homeowner also has to take other costs into consideration, including $50 to $300 for permits and $1,000 to $5,000 for replacing duct work. If there is an old oil boiler that is replaced with a different type, the homeowner must pay $500 to $3,000 for the removal of the tank.