# How much fuel does an air to fuel ratio controller save on a Panipat boiler or thermic fluid heater?

Canonical: https://senseible.earth/answers/panipat-air-fuel-controller-8-14-percent-saving

The Panipat survey by The Energy and Resources Institute (TERI) prints a saving of 8 to 14% of fuel from an air to fuel ratio controller on a boiler or heater, with a payback of 8 to 12 months. A controller trims the air so less heat is blown up the chimney.

## Why the amount of air matters

Fuel needs air to burn. Think of a gas stove. Too little air and the flame smokes. Too much air and the flame is cooled, and the extra air carries heat away. A boiler is the same: air beyond what burning needs is called excess air, and every bit of it leaves hot.

A thermic fluid heater is a furnace that heats oil instead of water. Textile units pump the hot oil to the stenter, the machine that stretches and heat-sets cloth, and to the printing section, like a hot-oil radiator for the machines.

## What TERI found and proposed

- Existing: estimated excess air of 110 to 160, based on design, with no control on combustion air. The table prints no unit; excess air is normally quoted as a percent, which is our reading.
- TERI notes boilers have no monitoring or control for flue gas temperature, steam pressure at the point of use, or the air to fuel ratio.
- Proposed: an air to fuel ratio controller with closed loop feedback of flue gas readings. Flue gas is the hot gas leaving the chimney. Closed loop means a sensor in the chimney gas reads the oxygen level and the controller adjusts the air by itself, like a thermostat.
- Energy saving potential: 8 to 14%. Simple payback: 8 to 12 months.

## What the controller is made of, per TERI

The survey lists a variable frequency drive (VFD) on the induced draft fan and the forced draft fan, working from the oxygen level and temperature of the flue gas. A VFD is a speed control for a motor, like a dimmer for a light. The forced draft fan pushes air in. The induced draft fan pulls gas out.

## How it fits our other pages

Our Pali page shows flue gas at 15 to 17% oxygen on pet coke boilers, which is far too much air, and a saving of about 98 tonnes of pet coke a year per boiler. That is a different cluster and a different report. The direction agrees with Panipat: more air than needed wastes fuel. The figures are not interchangeable.

## Example: a heater burning 20 tonnes of pet coke a month

- Saving at 8%: 20 × 0.08 = 1.6 tonnes a month, 19.2 tonnes a year
- Saving at 14%: 20 × 0.14 = 2.8 tonnes a month, 33.6 tonnes a year
- Carbon dioxide (CO2) at 3.17 tonnes for each tonne of pet coke: 1.6 × 3.17 = 5.1 and 2.8 × 3.17 = 8.9 tonnes a month
- A year: 19.2 × 3.17 = 60.9 up to 33.6 × 3.17 = 106.5 tonnes of CO2

Example only. Pet coke is a hard black fuel left over from refining oil, counted here at defaults from the Intergovernmental Panel on Climate Change (IPCC). Your own invoices and a before and after test decide your figure.

## What Senseible does here

Senseible reads your fuel invoices into monthly records, so the tonnes of pet coke or wood you buy each month are on file to compare before and after a controller goes in. It does not read a boiler or heater or measure the air, so those records come from your own invoices.

- [Green loan readiness check](https://senseible.earth/green-loan-check)
- [Pali pet coke boiler: automatic excess air control](https://senseible.earth/answers/boiler-excess-air-control-petcoke-saving)
- [Boiler fan drive saving](https://senseible.earth/answers/boiler-fd-id-fan-vfd-saving)
- [Panipat fuels and carbon](https://senseible.earth/answers/panipat-textile-cluster-fuels-and-carbon)

Sources: [TERI, Energy Profile: Panipat Textile Cluster, 2016 (SAMEEEKSHA)](https://sameeeksha.org/pdf/clusterprofile/PanipatTextileCluster.pdf), [IPCC, 2006 Guidelines for National Greenhouse Gas Inventories, Volume 2, Energy](https://www.ipcc-nggip.iges.or.jp/public/2006gl/vol2.html)

Last reviewed 2026-11-07. Figures are from the Panipat survey of 2014-15, published in 2016. The survey table prints each saving as a range with no boiler size, fuel tonnes or equipment cost. Check a current quote and your own fuel records before you rely on any payback.