A look at the cost of a new boiler and information about the different options available. How Much Will a New Boiler Cost? Average boiler replacement cost..See how much it costs to replace a boiler in with our recently updated price guide. Also, arrange your own no obligation quote from our trusted partner..A guide to gas boiler replacement costs. If your year old gas boiler has broken down and its finally time to start thinking about replacing then this guide to gas boiler prices can help.Boiler Replacement Costs Most boiler issues come down to weighing the costs and benefits of repair versus replacement. Repairs typi.y cost between $ and $, which can involve replacing key elements like heat exchangers, burners, chimneys or lines..