Boiler upgrade incentives

This tool estimates how many Energy Savings Certificates (ESCs) your project could receive for implementing efficiency upgrades to your gas-fired boiler. The estimations come from the High Efficiency Appliances for Business (Schedules F8 to F15) method in the Energy Savings Scheme (ESS).

To use the tool, simply click on the tabs below and fill in the fields provided. If you’re interested in getting more information on how ESCs can be created for your project, please click on the next step button. This will take you to a list of Accredited Certificate Providers (ACPs) that can help you access these incentives.


An economiser is a fluid-to-air heat exchanger that recovers waste heat from a boiler exhaust stack. The heat from the exhaust gasses is transferred to a water stream, usually boiler feedwater, which reduces the amount of work that the boiler has to do.

Economisers are particularly effective on steam boilers that have a high firing rate and a high stack temperature. Hot water boilers and water heaters generally have much lower stack temperatures. You must install a condensing economiser and have a corrosion resistant stack in order to recover heat at lower temperatures.

You can estimate the potential ESCs for installing an economiser below (using ESS Schedules F12).

As a boiler generates steam, the total dissolved solids (TDS) in the water that feeds into the boiler are left behind. The concentration of TDS builds up overtime and boiler needs to get rid of the dirty water through a process called "blowdown". If you can reduce the frequency of boiler blowdown, you can reduce energy loss. This can be done by installing a controller that blows down based on continuous readings of TDS in the boiler rather than being based on a simple timer.

When blowdown water exits the boiler, it depressurises and generates flash steam. This steam can be captured in a flash vessel and injected into the boiler feedwater tank. This process recovers heat and helps to deaerate and mix the water in the feedwater tank.

Once the steam has flashed off, it leaves behind hot water, referred to as residual blowdown. Energy can be recovered from residual blowdown via a fluid-to-fluid heat exchanger which preheats a cold water stream such as boiler makeup water.

You can estimate the potential ESCs for installing a sensor based blowdown control, a flash steam heat recovery system, and a residual blowdown heat exchanger below (using ESS Schedules F13, F14 and F15).

Boiler wear and tear can lead to reduced efficiency. This coupled with advances in design and properly sizing replacement boilers can create significant savings from replacing an old boiler.

The savings factors used in High Efficiency Appliances for Business (HEAB) method are conservative. You can generate upward of 10% savings from replacing a boiler depending on the condition of the existing boiler and the quality of the replacement.

If you’re replacing a boiler with a nameplate capacity larger than 2,000kW, you might want to consider using a measurement and verification method in the ESS. The measured savings and potential ESCs will likely be much greater than what you would receive using the HEAB method for which this tool was designed.

You can estimate the potential ESCs for replacing a steam boiler, hot water boiler or water heater below (using ESS Schedules F8 and F9).

The first principle behind efficient combustion in boilers is maintaining an appropriate air to fuel ratio. Boilers tend to run with too much air which leads to unnecessary heat loss through the boiler stack. If the amount of air is too low, you run the risk of fuel building up in the combustion chamber which increases the risk of explosion. A modern digital burner accurately sets the appropriate ratio and an oxygen trim system makes minor adjustments to the setting based on continuous measurement of oxygen concentrations.

The second way in which combustion is kept efficient is through the burner being able to reduce the firing rate as demand for steam or hot water decreases. This decreases the number of times that the boiler needs to cycle off, which leads to loss of heat through purging the combustion chamber of residual fuel.

You can estimate the potential ESCs for replacing burners and installing oxygen trim (using Schedules F10 and F11).

Boiler - ESCs calculator

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Burners - ESCs calculator

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Economiser - ESCs calculator

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Blowdown - ESCs calculator

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The Office of Environment and Heritage (OEH) has compiled this tool in good faith, exercising all due care and attention. No representation is made about the accuracy, completeness or suitability of the information in this tool for any particular purpose. OEH shall not be liable for any damage which may occur to any person or organisation taking action or not on the basis of this tool. Readers should seek appropriate advice when applying the information to their specific needs.

All content in this tool is owned by OEH and is protected by Crown Copyright. It is licensed under the Creative Commons Attribution 4.0 International (CC BY 4.0), subject to the exemptions contained in the licence. The legal code for the licence is available at Creative Commons. OEH asserts the right to be attributed as author of the original material in the following manner: State of New South Wales and Office of Environment and Heritage 2018.

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Page last updated: 09 April 2018