SearchEmail UpdatesContact UsResidentsBusinessVisitorsGovernmentOffice of the always open

Stay Connected

tumblr  facebook  Twitter

Ask for Clean Heat


NYC Clean Heat has transitioned into the NYC Retrofit Accelerator, New York City's new one-stop resource for energy and water efficiency. Larn more at


See below for answers to frequenty asked questions about completing a heating oil conversion.

For questions about the NYC Retrofit Accelerator or how to implement a wide range of energy and water upgrades, visit the Retrofit Accelerator FAQs page or contact the NYC Retrofit Accelerator directly to find out more.


What is Heavy Oil?

There are three grades of heating oil burned in New York City: No.6, No. 4, and ultra-low sulfur No. 2 (ULS 2) oil. The heaviest grade, No. 6 oil, resembles tar or asphalt. It is often referred to as a residual oil because it literally comes from "the bottom of the barrel" of the petroleum refinement process. No. 4 oil, a combination of No. 6 and ULS No. 2 oil, is also a heavy heating oil. For more information, see The Problem.

Why is it important to use cleaner fuels?

It protects your health. Because of its high sulfur content, burning No. 6 and No. 4 oil releases significant quantities of fine particulate matter (PM 2.5) in chimney exhaust, which is harmful to our health. NYC Clean Heat has already reduced PM 2.5 emissions by over 65%, which, combined with overall pollution reduction in New York City, is estimated to prevent hundreds of deaths and thousands of emergency room visits and hospitalizations from lung and cardiovascular diseases annually, compared to 2008.

It can save you money. Converting to cleaner fuels and increasing heating system efficiency can help buildings save money. The more efficiently the heating system is running, the less fuel a building needs. For more information, see The Problem.

How do I find out if my building burns No.6 or No. 4 oil?

Check out our Spot the Soot tool. Enter your address to see if your building burns heavy heating oil.

When will my building need to convert?

All Certificates to Operate No. 6 oil expired on or before July 1, 2015 and therefor all buildings using No. 6 oil are out of compliance and must convert immediately. Buildings that burn No. 4 oil have more time to convert, but why wait? For more information, see Regulations.

I want my building to convert to a cleaner heating fuel. How do I get involved?

See our page on What You Can Do and tell your building manager or managing board to contact the NYC Retrofit Accelerator, New York City's one-stop resource to help building owners and operators complete energy and water upgrades in their buildings.

What fuel options do I have besides heavy oil?

There are several fuel options, and the NYC Retrofit Accelerator can help you navigate the choices. Cleaner fuel choices include:

What are the financing options if a building does not have enough reserve funds to pay for the conversion?

See our page on Financing for information about the resources available to your building.

What is required to start the conversion process for my building?

Many buildings will be able to switch to one of the cleanest fuels using their existing equipment. Others may need to replace or upgrade components of their systems. Contact the NYC Retrofit Accelerator to answer any questions.

  • Know when you need to switch
  • Understand your conversion options
  • Consider energy efficiency
  • Obtain costs estimates
  • Contact your utility if necessary
  • Evaluate Incentives and Financing Options

For more detail, see the Steps to Conversion.

What is a firm gas rate?

Firm gas rates apply when a building burns natural gas only. Firm gas service will not be interrupted because of weather or other conditions. Rates are established by the New York Public Service Commission and tend to be slightly higher than interruptible gas rates. Firm gas customers are entitled to 100 feet of free gas main and 100 feet of free service to their building from their natural gas utility. 

What is an interruptible gas rate?

Interruptible gas rates are for customers who can burn either natural gas or oil. When required by the gas utility, interruptible customers agree to switch to oil or another energy source based on the gas utilities’ pre-established criteria. The interruptible gas rate may change from month to month, and may be lower than the firm rate. The upcoming month’s interruptible rate is published on the company website at the end of each month. Interruptible customers need to maintain 10 days of supply of ULS 2 oil.

What is a dual fuel firm gas?

Buildings that currently burn at least 70,000 gallons of oil annually can inquire with their gas utility about dual fuel firm gas. Buildings that maintain a dual fuel system pay the firm gas rate. They are also required to burn a minimum amount of gas each year with that amount set by the utility. The construction costs for bringing the gas main and service to the building are rendered through a “Revenue Test” which determines if the anticipated revenues from the building can offset the cost to bring service to the building. For more information, see our page on converting to Natural Gas.

What is an underground/buried tank?

The NYS Department of Buildings considers a tank to be a buried tank if the bottom of the vessel is beneath or in contact with the ground. Having the vessel in contact with the ground can lead to advanced corrosion and potential leaks that could remain undetected.

Is there a risk of gas explosion when natural gas is used for heating?

Most NYC buildings already have gas for cooking and dryers and use it without event. Risk of explosion due to natural gas is very small. Gas that is piped to buildings is also injected with an odorant so it can be easily detected.  Notify your gas utility if odors are evident.

Does the chimney need to be lined when switching to gas?

Masonry chimneys typically need to be lined with a stainless steel liner (10 or 20 gauge) as a result of the exhaust products generated from the burning of natural gas containing moisture which can destroy the mortar between the bricks. Buildings should work with a qualified professional to see if a chimney liner is needed. Chimney liners can cost in the range of $5,000 to $10,000 per floor.

Does the boiler or burner need to be replaced when switching to gas?

Replacement of the existing boiler will most likely not be required unless a licensed professional determines that the boiler needs to be replaced. Single fuel burners will need to be replaced, but very few buildings have them. Dual fuel burners are capable of burning both gas and oil. For more information, see our page on converting to Natural Gas.

Where can I find more information about additonal energy upgrades for my building?

During summer 2015, NYC Clean Heat transitioned into the NYC Retrofit Accelerator, which was announced in One City: Built to Last as the City’s flagship program to reduce GHG emissions from privately-owned buildings. The Retrofit Accelerator builds on the City’s Greener, Greater Buildings Plan (GGBP), which requires all buildings over 50,000 square feet in floor area to benchmark their energy use annually (Local Law 84 of 2009) and conduct energy audits and retro-commissioning once every ten years (Local Law 87 of 2009). The program provides outreach and technical assistance to help building owners use this information to identify energy and water conservation opportunities in their buildings and undertake a broad range of energy efficiency, water conservation, and clean energy investments. In addition, all of the services that have been provided through NYC Clean Heat to help building owners convert away from heavy heating oils and to cleaner energy alternatives continue to be available through the Retrofit Accelerator.