The reality of energy efficiency in tempering furnaces

The reality of energy efficiency in tempering furnaces

In the world of glass processing technology, particularly when it comes to tempering furnaces, we all agree on one point: energy saving is no longer an option, but an absolute priority. And it is an issue that cannot be approached with simplifications or purely strategic and commercial aims: energy consumption is an important technical issue.
 

When it comes to energy and glass, you cannot cheat: physics dictates the rules.
 

The physical principle before marketing
Before going into detail, it is important to clarify a technical point: in the past, the electric heating of tempering furnaces was by radiation only, with a control based on simple ON-OFF contactors, with obvious limits in terms of energy efficiency. Today, all new-generation hardening furnaces on the market adopt an advanced radiation control system. Thanks to the use of precision thermocouples and the use of solid-state relays (SSR) or, even better, silicon-controlled rectifiers (SCR zero crossing), electrical control is more stable and responsive, greatly improving energy management and, consequently, the overall efficiency of the system.
 

It is essential to remember that in every tempering furnace, the temperature of the heating chamber fluctuates between 680 °C and 700 °C, depending on the heating cycle, and that the glass must leave the heating chamber with a temperature between 630 °C and 640 °C to be properly tempered.
 

Real data, not promises

We at Keraglass design and manufacture tempering furnaces with a clear objective: concrete performance, real numbers, measurable and certifiable results. We cannot and will not hide behind misleading numbers or communication shortcuts.

Let us take a concrete example: tempering a 1 m² sheet of glass with a thickness of 4 mm requires at least 1.9 kWh of energy. A figure based on a real physical calculation:
 

E = ΔT × c × m,
 

where E is the energy required to heat the glass, ΔT the temperature change, c the specific heat capacity of the glass, and m its mass.
This value is a reference independent of the brand or technology of the furnace, and can only increase slightly depending on a few other factors such as: the number and type of thermocouples installed, the quality of the thermal insulation of the heating chamber,
the dispersions due to the construction of the furnace. Those who promise significantly lower energy consumption often do not tell the truth.
 

Efficiency is measured in productivity
The reduction of energy consumption must always be related to the final cost per square meter of processed glass, measured with appropriate instrumentation and evaluated in relation to thickness and real productivity.
Often, an apparent “saving” comes from reduced loads, slow cycles or plants operating under speed. But at what price? More time, less glass produced, lower margins.
At Keraglass, we prefer to talk about real profitability: furnaces designed to work at full load, with fast cycles, consistent productivity and constant quality.
This is how a plant becomes a real productive investment. This is demonstrated by our machines installed all over the world, which every day guarantee continuous production, optimised consumption and tangible results.
Our data is certified by independent tests and supported by real production: no simulations, no ideal scenarios. Just the reality of the industry.
 

Forward-looking technology
There is another aspect that is indispensable today: sustainability.
Choosing an efficient oven means saving energy, reducing emissions, limiting waste and contributing to a more responsible production model. For us, innovation also looks to the future of the planet. With Keraglass, you choose transparency, innovation and certified performance. Because a tempering furnace must not only consume less: it must make you earn more, without shortcuts. Choose those who guarantee real results, today and over time. Choose the truth.
 

Choose the technology that works better for you.