What a boiler replacement costs in Bridgeport and across Connecticut

The published ranges

National and Connecticut cost guides put a standard boiler replacement at about $3,700 to $8,300, with high-efficiency condensing boilers reaching about $12,000. Oil boiler replacements are published at about $4,800 to $9,000. Connecticut work tends to run above national averages, so treat the low end of any range with caution and expect older houses to land in the middle or above.

Those ranges cover the boiler and a normal installation. The items below are what turn a simple swap into a larger job, and they explain most of the difference between two quotes for the same house.

Boiler type and efficiency

A standard cast-iron boiler that vents into a chimney is usually the least expensive to buy and install. A condensing boiler costs more but burns less fuel, and it vents through the wall with plastic pipe instead of the chimney. A combi boiler adds domestic hot water in the same unit and can replace a separate water heater. See boiler replacement options for how we match the type to the house.

Venting and the chimney

Moving from an old boiler to a new one often changes the venting. A standard boiler going into an old masonry chimney usually needs a liner, and a condensing boiler needs a new sidewall vent and a condensate drain. If the water heater still uses the chimney after the boiler leaves it, the chimney may need a smaller liner so that heater vents safely.

Piping, controls and zones

Older systems were often piped for the boiler they had, not the one going in. Near-boiler piping, new circulators or zone valves, an expansion tank, air separation and an outdoor reset control are common additions. They add cost, but they are also what let a high-efficiency boiler actually run efficiently.

Steam is its own case

Steam boilers cost more to replace than most hot-water boilers because they have to be sized to the radiators, not just the heat load, and the near-boiler piping has to be built correctly or the system bangs and spits. If your house has steam, ask whether the quote includes a radiator survey and new near-boiler piping. See steam heat service for what that work involves.