What does insulation paint on a rotary furnace shell save in furnace oil?
In the Bureau of Energy Efficiency (BEE) report for foundries in Batala, Jalandhar and Ludhiana, paint on a 5 square metre rotary furnace shell cuts its skin from 120 to 60 degrees C and saves 715 litres of furnace oil a year, Rs 20,029, for Rs 21,284. Payback is 1.06 years.
How the saving is worked out
- The shell measured 120 C against 40 C ambient, with the air around the furnace at 80 to 90 C. The report expects the paint to bring the skin down to 60 C.
- Surface 5 square metres. Heat loss falls from 4,371 to 794 kilocalories (kcal) an hour, 3,577 less.
- At 10,000 kcal a litre and 2,000 hours a year (8 hours, 250 days): 874 litres lost before, 159 after, 715 saved.
- At Rs 28 a litre that is Rs 20,029 a year.
What the Rs 21,284 buys
- Primer Rs 4,875 (6.5 litres at Rs 750), top coat Rs 5,400 (4.5 litres at Rs 1,200), thinner Rs 787.50.
- Tax Rs 221.25 and Rs 10,000 for other costs. The paint itself is Rs 11,062.50.
- The report puts the paint's life at 3 to 5 years.
Check it on your furnace
Measure the shell with an infrared thermometer before and after. The 60 C is the report's prediction. Count furnace oil as oil bought plus opening stock minus closing stock, so the saving shows against your invoices.
The sum, and carbon dioxide (estimate)
- Heat saved: 3,577 kcal an hour / 10,000 = 0.358 litres an hour; x 2,000 hours = 715 litres
- 715 litres x Rs 28 = Rs 20,020 (the report rounds to Rs 20,029)
- Cost over saving: 21,284 / 20,029 = 1.06 years
- Carbon dioxide at 2.97 kg a litre: 715 x 2.97 = 2.12 tonnes. The report says 2.29 tonnes, about 3.2 kg a litre
Furnace oil at 2.97 kg carbon dioxide (CO2) a litre, an estimate from Intergovernmental Panel on Climate Change (IPCC) carbon content. Other figures from the Bureau of Energy Efficiency (BEE) report.
What Senseible does here
Senseible reads fuel invoices and electricity bills into monthly records with carbon dioxide equivalent (CO2e), so the months before and after the paint sit side by side. A small saving like this is easy to lose in a month's noise. The green loan check shows what a lender asks for.
- Green loan readiness check
- Oil fired rotary furnace to induction
- Reheating furnace insulation and fuel saving
- Kiln insulation and petcoke saving
Sources: BEE, Detailed project report: insulation paint on the outer surface of a rotary furnace, Batala, Jalandhar and Ludhiana foundry cluster (SAMEEEKSHA), IPCC 2006 Guidelines, Volume 2 Energy, Tables 1.2 and 2.3
Last reviewed 2026-11-04. Report figures are from a Bureau of Energy Efficiency (BEE) Small and Medium Enterprises (SME) programme project report; costs and paybacks are at the report year's prices. Check today's prices and a current quote before you rely on the payback.