FAQ's – Boilers / Hot Water Heaters / Tankless / combi
NYC FAQ's
Do I need a Licensed Master Plumber to replace my boiler or water heater in NYC?
Yes. A NYC Licensed Master Plumber is required. If the boiler or water heater is gas-fired, the individuals performing the gas work must also be properly qualified and registered with NYC DOB to perform gas work.
Replacing a boiler or water heater isn't simply a matter of disconnecting the old equipment and installing a new one. Permits are required, and the existing gas piping, chimney or venting system may need to be evaluated.
Proper venting is especially important. Gas-fired equipment produces carbon monoxide. If the equipment or venting system is installed incorrectly, those gases can enter the building and carbon monoxide can be deadly.
Always make sure your home has a working carbon monoxide detectors.
Replacing the equipment may be the easy part. Making sure it's installed safely and legally is just as important.
What happens if my boiler fails in the middle of winter?
NYC DOB has an emergency procedure called an Emergency Work Notification (EWN). During the heating season, an EWN can be filed for qualifying emergency repairs or replacement of heating or hot-water equipment in certain buildings.
An EWN is not a substitute for a permit. The required filing and permit process must still be completed after the emergency work begins.
So if your boiler fails during the winter, there is a legal procedure that allows your Licensed Master Plumber to address the emergency without waiting for the normal permit process.
Westchester FAQ's
Why can't my plumber just replace my old boiler with an updated boiler?
Because New York State code requires heating equipment to be properly sized. Manual J is used to calculate the heating requirements of the home, and Manual S is used to select equipment based on that calculated load.
This is especially important when replacing older boilers. Many older systems were oversized, so simply replacing an old boiler with another boiler of the same size may mean repeating the same mistake.
Bigger isn't necessarily better. The goal is to install the right boiler for the building.
Those giant cast-iron radiators weren't necessarily oversized for the buildings they were originally installed in. The buildings were different.
Old houses had little or no insulation, single-pane windows, substantial air leakage, and much higher heat loss than the same house may have today. They needed a lot of radiation to keep the building warm.
But there's another important piece: steam boilers are sized to the radiation, not simply to the present-day heat loss of the house. The connected radiators represent an EDR—Equivalent Direct Radiation—load. The boiler has to produce enough steam to fill that connected radiation and the piping.
Over the decades, somebody may have replaced the windows, insulated the attic, insulated walls, sealed drafts, or otherwise substantially reduced the building's heat loss. The radiators didn't shrink.
And that's where blindly applying the idea of "the old boiler was 200,000 BTUs, so put another 200,000 BTU boiler in" can go badly wrong.
What is a Boiler ?
New York State defines a boiler as "a closed heating appliance intended to supply hot water or steam for space heating, processing or power purposes."
Simply put, a boiler heats water. Depending on the type of system, that heated water either circulates through the building as hot water, or the boiler turns the water into steam that travels through the piping to radiators.
Boilers can be fired by different fuels. In our area, older systems are commonly natural gas or oil-fired, although the heating system itself may have been installed many decades ago. The boiler is also only one part of the heating system. Depending on the system, there may be radiators, baseboard, circulator pumps, expansion tanks, valves, controls, thermostats, vents, a chimney or other venting system, and miles of piping throughout the building. Replacing the boiler doesn't necessarily mean the rest of that system needs to be replaced.
And despite the terms sometimes being used interchangeably, a boiler is not a furnace. A boiler heats water or produces steam and distributes that heat through piping. A furnace heats air and distributes the heated air through ductwork.
Today, some property owners are choosing to remove older boiler systems altogether and replace them with modern HVAC or heat-pump systems. That can be a viable option, but removing a boiler and changing the way a building is heated involves more than simply taking the old equipment out. The existing piping, radiators, chimney, gas or oil equipment, electrical requirements, and applicable permits all have to be considered.
NYSHot Water Heaters
Not every home has a separate water heater. In many older homes, particularly those with oil-fired boilers, domestic hot water may be produced by a heating coil inside the boiler. This means the boiler may need to operate year-round—even in the middle of summer—just to provide hot water.
Some homeowners choose to separate the two systems by installing an independent water heater, allowing the boiler to provide heat while the water heater handles the domestic hot water.
Traditional gas-fired water heaters remain very common. They store a supply of heated water in a tank and use a gas burner to maintain the desired temperature. Because they burn gas, proper installation and venting are extremely important. The products of combustion, including carbon monoxide, must be safely vented outside the building.
Other homeowners are choosing to switch from gas to electric water heaters. Electric water heaters don't require a gas connection or combustion vent, but there are other things to consider, including the building's electrical capacity, operating cost and recovery rate.
What is recovery rate?
Recovery rate is how quickly a water heater can heat new cold water after the stored hot water has been used. It is generally measured in gallons per hour (GPH) at a specified temperature rise.
For example, let's compare two hypothetical 50-gallon water heaters from the same manufacturer:
A 50-gallon gas-fired model with a typical 40,000 BTU burner might recover approximately 42 gallons per hour at a 90°F temperature rise.
A comparable 50-gallon electric model with standard 4,500-watt elements might recover approximately 21 gallons per hour at the same temperature rise.
Same size tank. Very different recovery.
The gas-fired water heater can recover hot water at roughly twice the rate of the conventional electric model. That's something to consider in a home with several occupants, multiple bathrooms, or periods of heavy hot-water use.
Choosing a water heater isn't simply about whether the tank says 40, 50 or 75 gallons. Fuel source, recovery rate, household demand, gas availability, electrical capacity, venting and operating costs should all be considered.
The equipment examples and performance figures above are provided for general educational and comparison purposes only. Josephine The Plumber does not endorse or recommend any particular water-heater manufacturer based on this example. "The Water Heater Company" is a fictitious name used to illustrate the difference between comparable gas and electric water heaters.
Tankless Hot Water Heaters
A traditional gas-fired water heater stores 40, 50 or more gallons of hot water and maintains that water at the temperature selected on the thermostat. A tankless water heater works differently. There is no large tank of hot water waiting to be used. When you open a hot-water faucet, the unit senses the flow, fires the burner and heats the water as it passes through the heat exchanger. When the water stops flowing, the burner shuts down. That's why these units are commonly called on-demand water heaters. With a tankless water heater, there isn't a 50-gallon tank being continually maintained. You heat the water when you need it. How much gas can it save? Usually 30-40%. The difference in energy consumption can be substantial. That does not mean every homeowner will reduce their gas bill by 40%. Actual savings depend on how much hot water you use, how often you use it, incoming-water temperature, gas rates and the equipment being replaced. Does tankless mean endless hot water Essentially, yes—but endless doesn't mean unlimited capacity. A tankless water heater doesn't run out of stored hot water because there is no tank to empty. But every unit has a maximum amount of water it can heat at one time. That's especially important in New York. The colder the incoming water, the harder the unit has to work to bring it up to the desired temperature. Tankless equipment therefore needs to be sized according to both flow rate and temperature rise. It's Not Always a Simple Swap Replacing a conventional gas water heater with a tankless unit isn't necessarily a matter of removing the old tank and hanging a new unit on the wall. Tankless water heaters can have a much larger BTU input, so the existing gas piping needs to be evaluated to determine whether it can supply the additional load. Venting must be installed correctly, and condensing units require proper condensate disposal. The hot-water demand of the house also needs to be considered. Two showers running at the same time are very different from one shower. Add a dishwasher, washing machine or another fixture, and the demand changes again. Tankless can use considerably less energy, provide continuous hot water and eliminate the need to keep a tank hot around the clock—but it still has to be properly sized and properly installed
Energy StarCombination Units (Combi-Boilers)
A combination boiler, commonly called a combi boiler, combines two appliances into one compact unit. Instead of having a separate boiler and water heater, one appliance handles both jobs. It provides both space heating for the home and domestic hot water for showers, faucets and appliances.
When the house needs heat, the combi operates like a boiler. When you open a hot-water faucet, the unit produces domestic hot water on demand, much like a tankless water heater.
With a combi unit, there isn't a separate 40- or 50-gallon water heater continually maintaining a tank of hot water. You heat your domestic hot water when you need it.
One of the biggest advantages is space. A wall-hung combi can replace both a floor-mounted boiler and a conventional water heater, freeing up a considerable amount of room in a basement or mechanical room.
It can also eliminate the standby heat loss associated with a conventional storage water heater. Modern condensing combi boilers are designed to re-capture the exhaust heat instead of sending it up the chimney.
The amount of energy required to heat your house can be very different from the amount required to provide domestic hot water. A house may have a relatively small heating load but require considerably more capacity when two showers or several hot-water fixtures are operating at the same time. The combi therefore has to be selected for both the building's heating requirements and its domestic hot-water demand. Bigger isn't necessarily better. The goal is the right equipment for the building.
Like a tankless water heater, a combi doesn't have a storage tank to empty. It can continue producing domestic hot water as long as the demand remains within the unit's capacity. But endless doesn't mean unlimited. Every combi has a maximum flow rate, and New York's colder incoming water temperatures can significantly affect how much hot water the unit can produce.
Replacing a conventional boiler and water heater with a combi may require changes to the gas piping, venting, condensate drainage, heating piping and controls. Combi units can have substantial BTU inputs, so the existing gas piping must be evaluated to determine whether it can supply the additional load. The existing heating system—including radiators, baseboard, circulators and zone controls—also needs to be considered.
A combi can provide heating and domestic hot water from one compact, high-efficiency appliance—but just like a tankless water heater, it needs to be properly sized and properly installed.
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