If asbestos is found, the cost of replacing or repairing a residential boiler is likely to increase due to the time and labor involved in removing asbestos in accordance with hazardous materials guidelines. This cost estimate generally includes removing and discarding the old unit and all the lines and wiring necessary for the new system to work properly. Finally, you'll need to remove the old boiler and tank, which can vary in cost depending on several factors, including where the boiler is located. Electric boilers tend to have the lowest maintenance costs of all types, and you'll need to drain them approximately once a year to remove any sediment.
Installing a gas meter and gas lines, opening trenches from the main gas pipeline to the house, and removing the oil tank are all costs that would be incurred in an oil-to-gas conversion.