How NYC is Phasing Out Heavy Heating Oils

Michael Tobias
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    In 2011, the NYC Department of Environmental Protection published a rule to phase out heating oils No. 4 and No. 6, the two most polluting fuels used for space heating in the city’s buildings. These two fuels produce large amounts of particulate matter below 2.5 microns (PM2.5), associated with around 3,000 annual deaths in NYC at the time when the DEP published the new rule. Fine particulate matter affects the lungs and heart, and can also induce asthma attacks.

    The NYC DEP established a separate deadline to phase out each type of heating oil. In the case of No. 6, which is the most polluting, the deadline was established for June 30, 2015. As a result, its use in NYC is now very rare, and is in fact against the law! The established deadline to phase out No. 4 heating oil is January 1, 2030, since its causes less pollution than No. 6. However, if any boiler or burner using No. 4 heating oil is replaced before the deadline, conversion to a cleaner fuel is mandatory during the project.

    When the NYC DEP mandated the phase-out of No. 4 and No. 6 heating oil they were only used in 1% of buildings, but were responsible for 86% of soot pollution in the city. The NYC Clean Heat program was created in 2012 to guide the transition to cleaner fuels, resulting in more than 6,000 heating system conversions and a 65% reduction of PM2.5 emissions by 2015. The NYC Clean Heat program is now part of the NYC Retrofit Accelerator, which provides assistance with building upgrades in general, in addition to heating fuel conversions.

    Which Heating Fuels Are Allowed by the NYC DEP?

    After 2030, only three types of heating fuel will be allowed in NYC: ultra-low sulfur #2 oil (ULS 2), biodiesel and natural gas. Of course, property owners can also use alternatives that don’t require burning any fuel in the building, such a using Con Edison’s district steam service, or installing electric heat pumps.

    ULS 2 is the cleanest heating oil available in the market, reducing particulate emissions by more than 95% when it replaces heavy oils. ULS 2 is compatible with most boilers that use No. 4 heating oil, making it the most affordable upgrade option in most cases. The project only becomes expensive if a new oil tank is required. Compared with heavy heating oils, ULS 2 generally improves boiler efficiency while reducing maintenance costs.

    Biodiesel is a renewable fuel created from agricultural waste, used cooking oil, and other similar types of organic waste. Biodiesel users get a state tax credit in NYC, which is deductible from personal income tax or corporate tax. Conversion from No. 4 fuel oil to biodiesel is not as straightforward as using ULS 2, and the new system must be specially designed for it.

    ULS 2 and biodiesel blend is also allowed as a heating fuel in NYC, since it combines two accepted fuels. In addition, using the blend provides the advantages of both options: it is compatible with many boilers that use No. 4 heating oil, while getting the biodiesel tax credit. In fact, all ULS 2 oil in NYC is a blend to a small degree, since it is legally required to contain at least 5% biodiesel.  This requirement will be gradually increased to 20% by 2034.

    Natural gas is considered the cleanest fuel overall, producing even less emissions than ULS 2 and biodiesel. In addition, gas-fired systems have lower operation and maintenance costs. However, conversion from heating oil to natural gas is a more complex project than simply upgrading from No. 4 to ULS 2 oil. Consider that natural gas is delivered as a utility service by pipe, while heating oil and biodiesel are delivered, so you will likely require a new gas service entrance, or expanding the existing one to meet the added demand of a gas-fired boiler.

    Heating Options That Don’t Require a Boiler On-Site

    NYC buildings can meet their heating needs without using heating oil, natural gas or biodiesel directly. They can also rely on Con Edison’s steam service, an electric heat pump, or a solar thermal water heater.

    Steam is a special case. It can be an attractive upgrade option for property owners with boilers fired by No. 4 heating oil, who also happen to be located in a district with the Con Edison steam service. To phase out the oil-fired boiler, they just have to discard it and and connect to the district steam piping network.

    • If you already have hydronic piping and an oil boiler that uses No. 4 heating oil, there is no reason to go back to steam. The best solution is to keep hot water piping, while upgrading to a better boiler or a heat pump.
    • In new buildings, the best option is also hydronic heating, using either natural gas boilers or high-efficiency heat pumps.

    Solar thermal can be cost-effective for buildings with an ample roof that is free from shades. The advantage of solar thermal heating is that it consumes zero fuel while producing zero emissions. There may be a small pumping cost associated with taking hot water to the roof, but it is small compared with the cost of heating the water with fuel combustion or electricity. Just keep in mind that solar thermal systems are often unable to meet the full heating demand of a building, and serve better as backup for other domestic hot water systems.

    Solar thermal water heating is eligible for a 30% federal tax credit and a 25% state tax credit. If the system replaces an electric resistance heater, it can also get a rebate of up to $4,000 from the NYSERDA (New York State Energy Research and Development Authority).

    Electric heat pumps run on electricity, which is very expensive in NYC, but they compensate by using it very efficiently. As a result, the running cost of a heat pump is comparable to that of a natural gas boiler. There are two main types of heat pumps:

    • Air-source heat pumps have a typical coefficient of performance of 2.5
    • Ground-source heat pumps have a typical COP of 4

    In addition to operating with zero emissions, heat pumps can also help property owners consolidate equipment. Most models feature reversible operation, allowing them to take over space cooling loads in the summer. In other words, a heat pump can assume the role of both a boiler and a chiller.


    If your building uses No. 6 heating oil, it is unlawful and an upgrade must be carried out as soon as possible. On the other hand, if you use No. 4 heating oil there is still time until 2030, but you will be required to perform an early fuel conversion if you carry out any boiler upgrade. There are many upgrade options available, so getting in touch with a qualified engineering firm is highly recommended - they can help you determine what works best for your property.

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    Tags : Sustainability Building Code new york

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