Buying guide · Glass Tempering Furnaces · Updated August 2026
Glass Tempering Furnaces: The Buying Guide
A tempering furnace heats flat glass close to its softening point, then chills the surfaces fast with high pressure air. The surfaces go into compression and the core goes into tension. The result is safety glass that is several times stronger than the sheet you started with, and that breaks into small blunt pieces.
The furnace is usually the largest single purchase in a flat glass plant. It sets your bed size, your daily output and much of your power bill. This guide covers the types, the figures that decide the choice, and what a quote must contain. Every number comes from the machine data published on GlassMachines.net. No manufacturer here publishes a price, so request pricing for your bed size and glass mix.
What a tempering furnace does and where it sits on the line
Tempering is the last thing you do to the glass itself. Once a sheet is tempered you cannot cut it, drill it, grind it or notch it. Every hole, every notch and every edge has to be finished before the glass enters the furnace. That is why the furnace sits at the end of the cold line.
The normal order is cutting, breakout, edging or seaming, drilling and milling, washing and drying, then the furnace. After the furnace the glass ships as monolithic toughened glass, or moves to an insulating glass line, a laminating line or a heat soak furnace.
Two things upstream decide your yield. The first is edge quality, because a chipped edge starts a break in the quench. The second is washing, because dirt bakes onto the surface. The Fuchong FC-PG Series states that its output meets GB15763.2, GB9656, ECER-43 and ANSI Z97.1, but only clean, well finished glass gets there.
- Before the furnace: cutting, edging or seaming, drilling, washing and drying
- In the furnace: heating, oscillation, optional bending, quenching, cooling
- After the furnace: heat soak testing, insulating glass, lamination, shipping
Types and configurations
The first split is the heating method. Radiation furnaces heat with electric elements alone, like the Jinglass Infrared Radiation Tempering Furnace, which covers beds from 1250 x 2500 up to 4000 x 10000 mm. Forced convection furnaces blow hot air onto the surface as well. Convection is what lets you temper coated glass, because a Low-E coating reflects radiant heat. Many machines combine both, and the Yuntong PG Series Flat Tempering Furnace mixes boosted radiation, forced convection and contact conduction.
The second split is single chamber against double chamber. A double chamber preheats in one section and finishes in another. The Yuntong S Series states that this reduces heat shock to the glass and the equipment, and gives a production rate 15 to 100 percent higher than comparable single chamber lines. The Fuchong FC-SQPW Series uses the same idea on the FC-PG platform.
The third split is batch against continuous. In a batch furnace the load oscillates back and forth, then moves to the quench. In a continuous furnace the glass only ever moves forward. The Fuchong FC-LXPG Series uses a long chamber with an ascending temperature setting for this. Continuous lines suit thin glass in high volume.
The fourth split is flat against bent. Bending furnaces form the glass with pressing rollers just before the quench. Rigid shaft machines such as the Jinglass Horizontal Concave/Convex Bending Furnace bend across the rollers. Flexible shaft machines such as the Jinglass Longitudinal Concave/Convex Bending Furnace bend along them. Some machines do both, including the Fuchong FC-PWG / FC-QPWG range.
Automotive glass uses its own machines. The Jinglass Automotive Front Window Press Bending Furnace forms windshields with a servo-controlled press, and the Fuchong FC-LXWG Series is a continuous line for car side windows. Heat soaking is a separate machine again.
How it works, step by step
First the load is set out on the loading table. Layout matters, because a badly packed bed wastes heating capacity. The Jinglass Vulcan Intelligent Tempering Furnace uses machine vision to recognise the layout automatically.
Second the load enters the heating chamber and oscillates on ceramic rollers. Elements sit above and below, and on a convection furnace blowers push hot air through nozzles onto the glass. The Yuntong D Series uses a double outlet fan so the air stream reaches the surface directly. The Yuntong PG Series Flat Tempering Furnace was the first of its kind to use matrix-type heating control zones.
Third, on a bending machine, the pressing rollers close and form the arc while the glass is still soft. Fuchong states that its arc adjustment is automatic and needs no mould.
Fourth the load moves into the quench. High pressure air hits both surfaces through nozzle grids. This is where most of the installed power goes. The Yuntong T Series splits the quench into bays at different pressure, so the glass passes through the high pressure bay without stopping and the large fans run only briefly.
Fifth the glass cools, then leaves on the unloading table. Cycle time sets your loads per hour, and that figure changes with thickness and with coating.
The figures that decide the purchase
Compare furnaces at the thickness and glass type you actually run. Output at 4 mm clear glass tells you nothing about 10 mm Low-E.
Loads per hour is the figure buyers get wrong most often. On the Mappi International S.r.l. FOX Series and the Mappi International S.r.l. ATS 4.0 Series, clear glass at 3 mm runs at 25 loads per hour and 4 mm at 24, but Low-E at 10 mm drops to 7. On the Mappi International S.r.l. MTH Series, clear glass at 4 mm runs at 22, 6 mm at 16 and 19 mm at 4.
Power demand decides your transformer. The Mappi FOX Series averages 115 to 233 kW per hour at 4 mm, the ATS 4.0 Series 232 to 469, and the MTH Series 595 to 764. Yuntong quotes a minimum power demand per model, from 22 kW at 3 mm on the smallest bed to 2500 kW at 6 mm on the largest.
| Figure | Range across the machines listed | Why it matters |
|---|---|---|
| Loading area | 305 x 610 mm up to 4000 x 10000 mm, and 3300 x 20000 mm on the longest lines | Fixed for the life of the furnace |
| Minimum glass size | 100 x 260 mm to 150 x 280 mm on flat lines | Small parts will not track |
| Glass thickness | 1.6 mm on continuous lines, 2.2 mm on batch lines, up to 25 mm | Thin glass needs quench pressure, thick glass needs heating time |
| Loads per hour | 4 to 63 batches, by thickness, coating and chamber count | The only output figure that matters |
| Continuous capacity | 260 to 2224 m2 per hour on solar and appliance lines | Compare on square metres, not batches |
| Heating method | Radiation, forced convection, or a combination | Convection is required for soft-coat Low-E |
| Installed power | 85 kW on a test furnace up to 5600 kW on a large double chamber line | Sets the transformer and the supply contract |
| Energy per square metre | 2.5 to 2.8 kWh per m2 on continuous thin glass lines | The clearest way to compare running cost |
| Line footprint | 4.4 x 2.4 x 2.6 m up to 63 x 6.7 x 2.8 m | The building often decides the furnace |
Choosing by what you produce
Architectural flat glass with Low-E. Buy forced convection. The Jinglass Mid-Infrared Forced Convection Conjoined Double Chamber Furnace and the Jinglass Matrix Mid-Infrared Forced Convection Single Chamber Tempering Furnace both process single, double and triple silver Low-E at emissivity of 0.015 and above. The Yuntong S Series quotes a minimum emissivity of 0.01.
Insulating glass and laminated work. Flatness is what you are buying. A distorted pane will not seal well and will not pair with a matched sheet. Bent and tempered output from the Yuntong Z Series can be laminated or made into insulating glass afterwards.
Solar and photovoltaic glass. Use a continuous line. The Jinglass Solar Glass Horizontal Continuous Tempering Furnace handles 1.6 to 4 mm glass at up to 2224 m2 per hour. The Fuchong FC-LXPG Series covers 2.5 to 10 mm at 260 to 1030 m2 per hour and quotes 2.5 to 2.8 kWh per square metre.
Appliance and furniture glass. Beds are smaller and glass is thinner. The Yuntong L Series Continuous Tempering Line starts at a 610 x 1220 mm bed.
Automotive glass. Windshields need the Jinglass Automotive Front Window Press Bending Furnace or the Fuchong FC-ZLW Series. Side windows need the Jinglass Automotive Side Window Tempering Furnace or the Fuchong FC-WG Series. Bus side windows have their own machine in the Fuchong FC-SSWG Series.
Fire-rated glass. The Fuchong FC-HQPG Series is a convection furnace configured for hollow, laminated and coated fireproof glass from 6 to 12 mm, up to 2800 x 7000 mm.
Bent architectural glass. The Yuntong H Series covers radii from 180 mm out to 45 metres and the Yuntong Z Series reaches 3300 x 20000 mm. For complex shapes, the Jinglass Multi-Curve Bidirectional Bending Furnace works spherical, J-shaped, S-shaped and saddle-shaped curves.
Structural and overhead glazing. Add a heat soak furnace. The Handong Heat Soak Furnace holds 260 plus or minus 7 degrees C for one to eight hours and takes 3 to 25 tonnes per load.
What a quote should include
Ask for a line by line quote. A furnace quote that is one number hides the cost of what you will need in month two. Request pricing against this list from each manufacturer so you compare the same scope.
- Factory-direct machine price for the exact loading area, listed by model code
- Heating method and chamber count, stated as radiation, convection or a combination
- Guaranteed loads per hour at your thicknesses, for clear glass and Low-E separately
- Installed power, minimum power demand and the transformer capacity required
- Control system, recipe library, quality analysis software and any yearly fee
- Loading and unloading tables, and whether they are included
- Export crating and freight, with the incoterm, packing dimensions and weights
- Installation, including foundation drawings, air ducting and the electrical connection
- Commissioning, the acceptance test and the standards the output must meet
- Operator and maintenance training, on site and at the factory
- A spare parts list covering ceramic rollers, heating elements and drive belts
- Warranty length and how long spare parts stay available
Lead times, installation and running costs
A tempering furnace is built to order. Lead time follows the bed size, the chamber count and the bending option. Ask for a written build and shipping schedule, and ask what changing the loading area does to it.
Installation is a civil works job, not a delivery. Line lengths run from 4.4 metres on the smallest bed up to 63 metres on the largest, and Mappi quotes a plant length of 25 to 28 metres for the MTH Series. You also need space for the loading and unloading tables, and room to pull rollers out sideways.
Power is the running cost. Heating power runs from 230 kW on a small radiation furnace to 1250 kW per chamber on a large conjoined line, with quenching adding 160 to 250 kW. The Yuntong T Series states that its zoned quench reduces peak current by at least 20 percent and power consumption by up to 40 percent. The Yuntong D Series states heating efficiency improved by 15 to 30 percent.
Consumables are ceramic rollers, heating elements, drive belts and quench nozzles. Ask how a roller is changed and whether the chamber has to cool first. The Jinglass Automotive Side Window Tempering Furnace supports hot-state maintenance and independent lifting of a chamber. The Jinglass Vulcan Intelligent Tempering Furnace uses a dual-U transmission wheel design that keeps running if one belt fails.
Mistakes buyers make
Five errors cost real money.
- Comparing loads per hour at 4 mm clear glass. Your order book is not 4 mm clear. Low-E at 10 mm can drop a line from 24 loads per hour to 7. Ask for the whole table.
- Buying a radiation furnace and then taking soft-coat Low-E work. Coated glass reflects radiant heat. If you expect Low-E orders, buy forced convection from the start.
- Sizing the transformer to the average and not the peak. Minimum power demand runs from 22 kW on a small bed to 2500 kW on a large one. Get the peak figure in writing.
- Forgetting the minimum glass size. Flat lines here stop at about 100 x 260 mm. Smaller parts need a smaller machine or a carrier.
- Leaving heat soak out of the plan. Glass used overhead or structurally is normally heat soaked, and that is a separate furnace with its own footprint and a cycle of one to eight hours.
Machines on GlassMachines.net
Small and mid-size flat lines. The Mappi International S.r.l. FOX Series is the smallest here, in three loading areas from 1050x2300 to 1500x3200 mm, at 25 loads per hour on 3 mm clear glass. The Mappi International S.r.l. ATS 4.0 Series is the mid-range step, in eight loading areas up to 2500x5000 mm. The Yuntong PG Series Flat Tempering Furnace is the general purpose line, from a 305 x 610 mm bed up to 3050 x 6100 mm.
High output flat lines. The Mappi International S.r.l. MTH Series is the largest Mappi line here, in four loading areas from 2500x6000 to 3300x6000 mm. The Yuntong S Series uses a double heating chamber and reaches 63 batches per hour on 3 mm glass, with beds up to 3300 x 20000 mm. The Jinglass Mid-Infrared Forced Convection Conjoined Double Chamber Furnace runs the full Low-E series and can temper glass up to 2700 x 10000 mm in conjoined mode on a 2700 x 5000 mm furnace.
Continuous and thin glass. The Jinglass Solar Glass Horizontal Continuous Tempering Furnace handles ultra-thin photovoltaic glass from 1.6 mm at up to 2224 m2 per hour. The Yuntong B Series is the thin glass option among batch furnaces, tempering from 2.2 mm using pass-through quench zones that concentrate air pressure.
Bending and heat soak. The Jinglass Horizontal Concave/Convex Bending Furnace does flat and bend tempering on one line across 28 sizes. The Handong Heat Soak Furnace homogenises tempered glass at 260 plus or minus 7 degrees C, in eight sizes from 3 to 25 tonnes per load.
Specs to compare, in one list
- Loading area
- It is fixed for the life of the furnace and caps the largest panel you can toughen.
- Heating method
- Only forced convection heats soft-coat Low-E evenly enough to temper it.
- Loads per hour at your thickness and coating
- Output can fall from 24 loads per hour on clear glass to 7 on thick Low-E.
- Glass thickness range
- Thin glass needs quench pressure and thick glass needs heating time.
- Minimum glass size
- Parts below about 100 x 260 mm will not run on a normal flat line.
- Installed power and minimum power demand
- It sets the transformer, the supply contract and most of the running cost.
- Bending capability and radius range
- The minimum radius decides which curved jobs you can quote.
- Line length and plant footprint
- Lines run from about 4 metres to 63 metres, so the building often decides the furnace.
Questions buyers ask
What is the difference between a radiation and a convection tempering furnace?
A radiation furnace heats the glass with electric elements alone. A convection furnace also blows hot air onto the surface. Coated glass reflects radiant heat, so convection is what makes even heating of Low-E possible. The Jinglass Infrared Radiation Tempering Furnace is a radiation line for facade, window and furniture glass. The Jinglass Matrix Mid-Infrared Forced Convection Single Chamber Tempering Furnace processes single, double and triple silver Low-E at emissivity of 0.015 and above.
How many loads per hour will a tempering furnace produce?
It depends on thickness, coating and chamber count. Clear glass at 3 mm runs at 25 loads per hour on the Mappi International S.r.l. FOX Series and the Mappi International S.r.l. ATS 4.0 Series. Clear glass at 19 mm runs at 4 loads per hour on the Mappi International S.r.l. MTH Series. Double chamber lines go higher: the Yuntong S Series reaches 63 batches per hour on 3 mm glass. Ask for the full productivity table.
What is the thinnest glass a furnace can temper?
Batch furnaces here go down to 2.2 mm on the Yuntong B Series, and 2.5 mm is offered as an option on several radiation and convection lines. Continuous lines go thinner: the Jinglass Solar Glass Horizontal Continuous Tempering Furnace handles photovoltaic glass from 1.6 mm. Thin glass needs concentrated quench pressure, so check the quench design and not just the stated minimum.
How much power does a glass tempering furnace need?
Far more than the rest of the cold line together. Installed power runs from 85 kW on a small test furnace up to 5600 kW on a large conjoined double chamber line. Average consumption at 4 mm runs from 115 kW per hour on the smallest Mappi bed to 764 kW per hour on the largest. Get the peak demand figure in writing before your electrical contractor quotes the supply.
Can one furnace do both flat and bent glass?
Yes. The Fuchong FC-PWG / FC-QPWG range is built as a double-direction furnace that produces flat and bent tempered glass on one line, and the Jinglass Horizontal Concave/Convex Bending Furnace lists flat and bend tempering in a single line across 28 sizes. Expect lower flat output than a dedicated furnace of the same bed size, and check the minimum radius against the shapes you sell.
Do I need a heat soak furnace as well?
You need one if you supply tempered glass for overhead, structural or high-rise use, where a nickel sulphide inclusion could cause a break in service. Heat soaking is a separate machine, not a furnace setting. The Handong Heat Soak Furnace holds 260 plus or minus 7 degrees C for one to eight hours, takes 3 to 25 tonnes per load, and records multi-channel temperature curves once a minute for the report.
