Boiler and Furnace Repair, Replacement and Installation in Windham, NH
Gas and oil, installed and repaired, all makes and models
What this work is
Gas and oil boilers and furnaces are what most southern New Hampshire houses still run on, and this covers all of it, install, replacement and repair, on every make and model.
Here is the part worth reading first, in the same words that have been on this business since the day it opened. "If a unit is able to be repaired and if doing so is cost effective for the customer, then a repair will be our first recommendation." A boiler that is twenty years old is not automatically a boiler that needs replacing. Cast iron sections outlive their controls by a wide margin, and a great many five figure quotes are written against a system that needed a circulator, an aquastat, an ignition module or a good cleaning.
That said, there is a real line, and you will hear when your system crosses it. A cracked heat exchanger, a leaking section, a failed unit that would cost most of a replacement to repair, or a system so far out of date that parts have to be hunted down. When it is time, it is time, and the honest answer runs in both directions.
Both fuels are covered, which is less common than it sounds. The NH gas license covers natural gas and propane boilers, furnaces and wall hung condensing units. The NH oil heating technician license covers oil fired equipment, burners, nozzles and pumps. Southern New Hampshire is split between the two, sometimes street by street, and six years co-owning an oil company means the oil side gets the same fluency as the gas side.
On a replacement, the near boiler piping is where the quality shows and where corners usually get cut. Proper primary secondary piping, correct circulator placement, a real air and dirt separation strategy, clean venting, and a system that gets purged and balanced before anyone leaves. Done right the first time is not a slogan on this one, it is the difference between a boiler that runs quietly for twenty years and one that gets a service call every winter.
What it costs
What this costs in southern New Hampshire
Nobody in this county publishes a number, which is exactly why these are here. The figures below are what the market charges, gathered from published cost data rather than from a quote sheet. Your house sets the final number, and you hear it before anything starts.
| Typical replacement | Published market range |
|---|---|
| Gas boiler replacementThe boiler itself is commonly $1,400 to $5,600 of that. The rest is the install. | $4,000 to $9,000 |
| Oil boiler, standard efficiencyDepends on system type and size. | $3,300 to $7,200 |
| Oil boiler, high efficiency | $6,300 to $9,000 |
| Warm air furnace, installedHigh efficiency and difficult installs run past the top of that band. | $3,500 to $7,500 |
| Oil tank replacementA separate job that often lands in the same conversation. | $1,000 to $6,200 |
Market data read directly from HomeGuide's 2026 boiler replacement and new furnace cost guides on July 31, 2026. Northeast installs run roughly 15 percent above the national figure. Your fuel, your venting and your near boiler piping decide where in the band a real job lands. These are market ranges, not our rates.
What moves the number on your house
- Fuel and equipment type
- A gas wall hung condensing combi, a cast iron oil boiler and a warm air furnace are three different projects with three different price structures.
- Venting
- Reusing an existing chimney is one job. A high efficiency unit that needs new direct vent piping through a rim joist is another, and the exterior work is part of it.
- Near boiler piping
- How many zones, what condition the existing piping is in, and whether it gets reused or rebuilt properly. This is where a cheap quote and a good one separate.
- Domestic hot water
- Whether the new system carries hot water through a coil, an indirect tank or a separate water heater changes both the equipment and the piping.
- Removal and disposal
- Old cast iron boilers are heavy, sometimes need to be broken down in place, and always need to leave the house and be disposed of correctly.
- Permits and code
- Gas work is permitted and inspected. That is a good thing, it is part of the schedule, and it belongs in the number up front.
If you already have a replacement quote in hand, bring it. A second opinion on somebody else's number is a normal thing to ask for and it is a normal thing to give.
Repair or Replace? Read This First
What you get out of it
Gas and oil boiler and furnace installation, replacement and repair across southern New Hampshire, including wall hung condensing units and full system changeouts.
- Licensed for gas and for oil, so the fuel in your basement is not a problem
- Repair gets recommended when repair is genuinely the right call
- All makes and models, including wall hung combi units
- Full changeouts with near boiler piping done properly, not just swapped
- Indirect water heaters, zone valves, circulators and controls
- Yearly cleaning available so the new system stays under warranty and stays safe
Two licenses, two fuels
Southern New Hampshire runs on both fuels, and so does this license set
GF1910596
NH Gas License
Licensed by the State of New Hampshire to work on natural gas and propane appliances, including boilers, furnaces and wall hung units. You can look the number up.
HT2300476
NH Oil Heating Technician
Licensed for oil fired heating equipment, burners and oil tanks. Southern New Hampshire runs on both fuels, and plenty of contractors are licensed for only one.
Certified
EPA Section 608
Federally certified to handle refrigerant, which is what every mini split, heat pump and central air system runs on. It is required by law, and it is worth checking.
Fully insured
Gas and oil are separate state licenses for a reason, and plenty of contractors around here hold one and not the other. Both are published below with their numbers, because a badge on a website proves nothing and a license number can be looked up.
Boilers & Furnaces, answered
- Is it worth repairing my boiler or should I replace it?
- Start with three questions. What actually failed, what does that part cost against the price of a new system, and what condition is the rest of the unit in. A control board, circulator, aquastat or ignition module on an otherwise sound boiler is almost always worth repairing. A cracked section, a leaking heat exchanger or a failure that costs most of a replacement is where the answer flips. You get told which one you are looking at, with the panel open so you can see the same thing.
- How long should a boiler or furnace last?
- A well maintained cast iron boiler frequently runs 25 to 30 years, and some run longer. Warm air furnaces tend to land in the 15 to 20 year range, and wall hung condensing units usually land shorter than cast iron because they run harder and have more electronics. Age alone is not a reason to replace anything. Condition is.
- Do you work on oil as well as gas?
- Both, and they are separate licenses for a reason. NH Gas license GF1910596 covers natural gas and propane equipment. NH Oil Heating Technician license HT2300476 covers oil fired equipment and burners. Plenty of contractors in this area hold one and not the other, which is worth asking any of them.
- My boiler is making a noise it did not used to make. Is that urgent?
- It depends on the noise. Banging and knocking in the pipes usually points to air, circulation or an expansion tank issue and it is worth looking at soon. Rumbling or kettling inside the boiler itself often means scale or a flow problem and it should be looked at quickly. A smell of gas or oil, or any soot, means stop using it and call. Describe the sound when you call and you will get a straight answer about how fast it needs attention.
- What is a wall hung combi boiler and should I get one?
- It is a compact high efficiency gas boiler that handles both your heat and your domestic hot water in one unit hung on the wall. They are excellent in the right house, particularly where basement space is tight or there is no room for a tank. They demand clean water, correct sizing and annual service, and they are less forgiving of neglect than a cast iron boiler. Whether one suits your house is a real conversation, not a default recommendation.
Last updated 2026-07-30
Tell me what your system is doing.
Send the details and Brian reads them himself. Free estimates on installations and replacements, straight answers on repairs, and the same person on the phone as in your basement.
- 24
- Years in the trades
- 8
- Years in HVAC
- 6
- Years co-owning an oil company
- 3
- Licenses and certifications