This is a practical challenge for many long‑established manufacturers. Industrial electricity and gas prices have risen substantially over recent years. Many old furnaces installed a decade ago feature poor thermal insulation and imprecise temperature control, consuming more than 20% extra energy compared with new‑generation furnaces. Replacing them with brand‑new units requires an investment of hundreds of thousands, which many enterprises are reluctant to bear. Yet without upgrades, they suffer from painful monthly electricity and gas bills.

Two scenarios should be considered. If the old furnace suffers from corroded and deformed steel structure, crumbling refractory materials, and severe furnace body distortion that damages product yield, building a new furnace makes more economic sense. Modern newly‑built furnaces come with inherent energy‑saving designs, cutting energy consumption by over one‑third versus furnaces from ten years ago. If the furnace structure remains sound but suffers from high energy consumption and sub‑standard emissions, retrofitting is far more cost‑effective, costing only 1/5 to 1/3 of new‑build expenditure.

Payback period depends on the scope of retrofitting. For medium‑sized furnaces with only refractory lining and sealing components replaced, the investment is around 100,000‑200,000, and energy savings can offset costs in roughly one year. If combustion system upgrading is included, overall energy‑saving rate can reach 25%‑40%, with payback commonly achieved within two years. Among retrofitting projects I have handled, the fastest payback took 8 months and the longest 18 months. For furnaces running continuously over 12 hours per day, savings from retrofitting will quickly recoup capital outlay, generating pure profit afterwards.