# How much power do eco ventilators save in a foundry shed compared with exhaust fans?

Canonical: https://senseible.earth/answers/foundry-eco-ventilators-replace-exhaust-fans-kwh

In the Batala, Jalandhar and Ludhiana foundry report, six 1 HP exhaust fans replaced by 36 wind-driven eco ventilators save 22.5 MWh a year in a typical unit, shown as 18.2 tonnes CO2. Installation takes 3 to 4 days of downtime.

## What was replaced

- 6 exhaust fans, 1 HP each, 0.75 kW per fan: 4.5 kW in all.
- Running 5,000 hours a year: 4.5 x 5,000 = 22,500 kWh.
- 36 eco ventilators, six for each fan, which need no power.

## How an eco ventilator works

Wind spinning the vanes, with the pull of hot fumes rising, draws air out of the shed. A flywheel effect keeps it turning when the breeze drops. It suits plants with a shed structure.

## What it does not do

It saves only what the fans used. A furnace that needs forced extraction at the hood still needs it. The saving assumes the fans can be switched off for good.

## Downtime

The report allows 3 to 4 days to fit the ventilators.

## Worked CO2 from the report's numbers

- Saving: 22,500 kWh a year.
- The report shows 18.2 t CO2, about 0.81 t per MWh.
- At the FY 2025-26 grid factor of 0.675 kg CO2 per kWh: 22,500 x 0.675 = 15,187 kg, or 15.2 t.

The report dates from 2011; use the grid factor for the year of your bills.

## What Senseible does here

Senseible reads electricity bills into a monthly kWh record, so a saving like this shows up as a lower line on the same bills.

- [Spectrometer saving in the same cluster](https://senseible.earth/answers/foundry-spectrometer-molten-metal-power-saving)
- [Induction foundry kWh per tonne by size](https://senseible.earth/answers/induction-foundry-kwh-per-tonne-by-size)
- [Carbon calculators](https://senseible.earth/calculators)

Sources: [SAMEEEKSHA and BEE, DPR: eco ventilators in place of exhaust fans, Batala, Jalandhar and Ludhiana foundry cluster](https://sameeeksha.org/pdf/dpr/Batala_Jalandhar_Ludhiana_foundry_cluster/Installation_of_eco_ventilators_in_place_of_exhaust_fan_Batala_Jlndr_Ludh_Fdry_Cluster.pdf)

Last reviewed 2026-11-03.