Furnace or Boiler? How to Tell What Actually Heats Your Rhode Island Home

The thirty-second test

Walk into any room and look at what delivers the heat.

• Radiators, the cast iron kind under the windows or the slimmer panel kind: boiler.
• Baseboard units running along the bottom of the walls, with fins inside a metal cover: boiler, heating water.
• Warm floors with nothing visible in the room at all: boiler, running radiant tubing.
• Vents, registers or grilles in the floor, wall or ceiling that blow warm air when the heat is on: furnace.

Then go to the basement. A boiler has water pipes coming off it, usually copper or black iron, often with a round expansion tank and one or more small pumps nearby, and there is no big rectangular duct. A furnace has large sheet-metal ducts coming off the top, a filter slot on the side, and no water pipes except perhaps a small one for a humidifier.

That is the whole test. A boiler heats water and sends it around the house. A furnace heats air and blows it around the house. Everything else follows from that.

Why Rhode Island is boiler country

Most of the state's housing was built before forced air became the default, and it was built for hot water or steam heat. The triple-deckers, the mill housing, the capes and the pre-war colonials that make up so much of Providence, Pawtucket, Warwick, Cranston and the East Bay were plumbed with radiators, and later generations swapped those for baseboard without changing the boiler underneath. Oil heat, which dominated here for decades, was overwhelmingly boiler heat. Steam boilers still run thousands of older houses across the state.

Furnaces show up in Rhode Island mostly in ranches and newer construction where central air conditioning was part of the plan, because a furnace and an air conditioner share the same ducts. If your house was built with central air, or added it during a renovation, there is a fair chance you have a furnace. If your house has never had ducts, you almost certainly have a boiler.

Why the two words get mixed up

Honestly, because it does not matter to most people until something breaks. Both live in the basement. Both burn gas, oil or propane. Both make the house warm and both stop doing it at two in the morning in January. For a lot of Rhode Islanders, furnace is simply the word for the heating thing downstairs, the way people say Kleenex for any tissue. There is nothing wrong with that, right up until you need to call someone.

Why it matters who you call

Boilers and furnaces are serviced by different trades with different licenses. A boiler is a plumbing and heating system: water, gas piping, venting, pumps, controls. It is repaired by a plumbing and heating contractor, which is what SOS is. A furnace is an air system: burners, a blower, a heat exchanger, ducts. It is repaired by an HVAC contractor.

Call the wrong trade and the best case is a wasted phone call. The worse case is a dispatch fee to have someone stand in your basement and tell you they cannot help, or a technician who is not licensed for what you have doing it anyway. A good company of either kind will ask a question or two on the phone and tell you which you have before anyone drives anywhere. We do.

What SOS services

Boilers, in every form Rhode Island houses have them. Hot water boilers feeding baseboard, radiators and radiant floors. Steam boilers in the older housing stock. Oil, gas and propane fired units. High-efficiency condensing boilers and the combination units that also make the domestic hot water. We repair them, maintain them, replace them and convert them from oil to gas, and we are certified installers for Navien, Viessmann, Utica and Burnham. Water heaters, tank and tankless, are ours as well.

What SOS does not service

Furnaces. Also ductwork, central air conditioning, heat pumps and mini splits. Those are HVAC, and rather than do a poor job of pretending otherwise we will tell you in the first minute of the call that you need an HVAC company. Nobody should pay us to discover that in their basement.

The hybrid that fools everyone: hydro-air

Some Rhode Island homes, particularly ones built or renovated in the last thirty years, have vents in the rooms and a boiler in the basement. That is a hydro-air system: the boiler heats water, the water runs through a coil inside an air handler, and a blower pushes warm air through ducts. It gives the house central air in summer off the same ducts. If that is what you have, the boiler and its piping are ours and the air handler, blower and ducts are HVAC. It is worth knowing which half has failed before you call either.

If you searched for furnace repair and you have a boiler

You are in the right place after all, and the symptoms translate directly.

• No heat at all: check the thermostat, the red emergency switch and the breaker, reset a lockout once and only once, then read our no-heat page and call. Someone answers at any hour and there are no overtime charges.
• Banging or hammering pipes: on a steam system that is usually water where it should not be, on hot water it is often air or a circulator. Both are boiler repairs.
• Some rooms cold, others fine: a zone valve, a circulator or air in the line, not a dead boiler.
• Water on the floor near the boiler: a relief valve, a fitting, or the boiler itself. Shut it down and call.
• Pilot will not stay lit: a thermocouple on an older gas boiler, an ordinary repair.

And if the test above says you have a furnace, we are sorry not to be able to help, and glad you found out here rather than from a dispatch fee.