Hot water or steam, gas or oil, cast iron or condensing—calculate the full replacement cost including boiler, piping, controls, and labor before you give a number at the kitchen table.
Steam boiler replacement is not a swap-and-go job. Steam systems require correct near-boiler piping—header, wet return, equalizer—or the system will waterlog and fail within months. If you're not trained in steam, bring in a steam specialist or partner with one. A poorly installed steam boiler is a callback that ruins your reputation and costs more to fix than the original job paid.
High-efficiency condensing boilers (90%+) cannot use an existing metal flue—they require PVC venting with a concentric kit or separate intake/exhaust pipes. They also produce acidic condensate that needs a drain route (floor drain or condensate pump). These are not optional—they're code requirements. Price the PVC vent kit ($150–$350) and condensate management into every condensing boiler quote.
If you're replacing a zoned boiler and the zone valves are more than 10 years old, they'll fail within 2 seasons anyway. Replace them at time of boiler install—labor is already on-site and the customer has already committed to the spend. A zone valve failure in year 2 is not a boiler problem, but you'll own the callback. Document what you replaced and what you left.
The HVAC Business Starter Kit includes a boiler sizing cheat sheet, service agreement template, and flat-rate price book for 35 common heating and cooling jobs. Guide from $19 — Complete Kit with all 19 templates, $49.
Get the HVAC Kit →Boiler replacement pricing is complex: boiler type and efficiency, piping modifications, flue venting, controls upgrade, permit fees, and whether the distribution system needs balancing after install all affect the total cost. This calculator builds a complete replacement quote from each component so you're not ballparking a number on a job this size.