Athermal windshield: what is it and why is it needed in a car?

In the summer, the car interior can be unbearably hot, and in the winter it can be cold, despite the working heater. This is usually due to windshield, which transmits up to 80% of solar heat. The solution to the problem is athermal windshield - an innovative coating that blocks infrared rays, maintaining a comfortable microclimate. But what is it really? Is it worth overpaying for such glass or is this a marketing ploy?

Many car owners confuse athermal coating with tinting or sun protection film. In fact, these are fundamentally different technologies. Atermalka does not obscure the view, does not violate light transmission laws, but at the same time effectively reflects heat. In this article we will look at how athermal glass works, what its pros and cons are, how to choose and install it.

What is an athermal windshield and how does it work?

Term "athermal" comes from Greek athermos - “not heating up.” This is glass with a special coating that reflects infrared (heat) rayswithout letting them into the salon. At the same time, visible light passes through almost without loss - light transmission remains at the level of 70-85%, which corresponds to GOST.

The technology is based on the application of a thin metallized layer (most often of metal oxides) between layers of triplex. This layer acts as a mirror for IR radiation, but remains transparent to the human eye. Unlike tinting, athermal does not change the color of the glass - it remains colorless or slightly greenish (depending on the manufacturer).

Efficiency depends on the amount and composition of the spray. For example, glass with double silver plated (like Saint-Gobain Sekurit) block up to 50% of heat, and models with triple layer (for example, Pilkington Optitherm) - up to 65%. At the same time, ultraviolet radiation (UV) is also partially delayed, which protects the leather and interior plastic from fading.

• 🔬 Example of work: In the heat of +30°C, ordinary glass heats the interior up to +50°C, and athermal glass only up to +35-40°C.
• ☀️ UV protection: Blocks up to 99% of ultraviolet radiation (for comparison: ordinary glass - only 30-40%).
• 🚗 Legality: Does not require approval from the traffic police, as it does not change light transmission.

Advantages of athermal glass: why is it beneficial?

The main advantage is reduction in interior temperature by 10-15°C in summer. This means that the air conditioner will turn on less often, and fuel (or battery power for electric vehicles) will be used more economically. According to tests ADAC, athermalka reduces the load on climate control by 20-30%.

The second key advantage is protecting the interior from burnout. UV rays destroy plastic, leather and seat fabric, causing cracks and discoloration. Athermal glass extends the life of the upholstery and dashboard. For example, in cars Toyota Camry and Volkswagen Passat With the factory seal, the interior remains like new even after 5 years of operation.

Additional advantages:

• ❄️ Winter comfort: The glass cools down more slowly, which reduces the formation of ice from the inside.
• 🔇 Noise insulation: The multilayer triplex structure dampens external noise by 10-15%.
• 💰 Savings: Less air conditioning consumption = less wear on the compressor and less freon refilling.
• 🛡️ Security: In the event of an accident, the fragments remain on the film without scattering throughout the cabin.

⚠️ Attention: Athermal glass does not replace tinting! It does not hide the interior from prying eyes and does not protect from the blinding sun (for this you need curtains or sunglasses).

Disadvantages and myths about athermal glass

Despite the obvious advantages, the technology also has disadvantages. Main - price. Factory-made athermal glass (for example, on Skoda Octavia or Hyundai Tucson) costs 30-50% more than usual. Installation of an after-sales option will cost 15-30 thousand rubles, depending on the car model.

The second disadvantage is difficulty of replacement. Not all workshops undertake the installation of athermal glass due to the risk of damaging the coating. Requires special cutting equipment and high adhesion adhesive. For example, when replacing with Audi A4 craftsmen often refuse to give a guarantee if the glass is not original.

Common myths:

• 🚫 "Athermalka completely blocks heat" - in fact, it reduces heat, but does not eliminate it completely.
• 🚫 “Such glass transmits light worse” — light transmission remains within GOST (not lower than 70%).
• 🚫 "Athermalka interferes with the operation of radar detectors" — the metallized layer is too thin to affect the signal.

⚠️ Attention: Cheap athermal glass (for example, made in China) may have a non-uniform coating, which causes optical distortions - “waves” or blur when viewed at an angle. Always check the quality certificate!

How to distinguish athermal glass from regular glass: 5 ways

If you are buying a used car or doubt that you have an automatic transmission installed, there are several ways to check. The easiest one is to look at marking in the corner of the glass. Usually it says:

• ATHERMAL, AT, IR-CUT - a clear sign of athermal coating.
• UV-CUT or SOLAR - can mean both athermal and UV protection without heat reflection.
• Lack of markings - most likely ordinary glass.

Other methods:

1. Lighter test: Bring the flame to the glass from the inside. Regular glass will heat up quickly, but athermal glass will remain cool.
2. Reflection check: Look at the glass at a 45° angle. Atermalka gives a slight rainbow tint (due to the metallized layer).
3. IR thermometer: Heat the glass with the sun and measure the temperature on both sides. A difference of 10°C or more indicates an athermal coating.
4. Ultraviolet lamp: Illuminate the glass with a UV lamp. Regular glass will allow the violet glow to pass through, but athermal glass will not.

Verification method	Regular glass	Athermal glass
Marking	None or standard (E1, DOT)	ATHERMAL, AT, IR-CUT
Heating with a lighter	Heats up quickly	Stays cool
Reflection at an angle	Neutral	Rainbow shade
IR thermometer (temperature difference)	Less than 5°C	10°C or more
UV lamp	Transmits violet light	Blocks UV radiation

Top 5 manufacturers of athermal glass: which one to choose

Not all athermal glass is created equal. The quality depends on the spraying technology, the number of layers and the brand. The market leaders are European and Japanese manufacturers, but there are also worthy Chinese analogues.

Top Brands:

• 🥇 Saint-Gobain Sekurit (France) - double silver coating, blocks up to 50% of heat. Installed on Renault, Peugeot, Citroen from the factory.
• 🥈 Pilkington (UK) - technology Optitherm with a triple layer, efficiency up to 65%. Popular in premium cars (BMW, Mercedes).
• 🥉 Asahi Glass (AGC) (Japan) - glass Suntek with an ultra-thin coating that does not distort the view. They bet on Toyota and Lexus.
• 4️⃣ Guardian (USA) - a budget option with good UV protection, but poor thermal insulation (up to 30%).
• 5️⃣ FYG (China) - inexpensive glass for Chinese cars (Geely, Changan), but the quality of the coating is unstable.

When choosing, pay attention to:

• 📜 Certificate of Conformity (must be in accordance with GOST R 51757-2001).
• 🔍 Guarantee (minimum 2 years coverage).
• 🚗 Compatibility with car brand (some glasses require modification of the fastenings).

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Before purchasing, check to see if there is a manufacturer's service center in your area. For example, glass Sekurit officially serviced only in 20 cities of Russia.

Installing athermal glass: step-by-step instructions

Replacing your windshield yourself is a risky undertaking. Installation errors will lead to leaks, squeaks or peeling of the coating. It’s better to entrust the work to professionals, but if you decide to do it yourself, follow the algorithm:

1. Removing old glass: Remove the seals, disconnect the wipers and rear view mirror. Carefully cut off the sealant with a knife or a special string.
2. Cleaning the opening: Remove any remaining adhesive and rust (if present). Treat the surface with a degreaser.
3. Trial installation: Try on the new glass without glue, check the alignment of the holes for the sensors.
4. Application of sealant: Use 3M PU 590 or SikaTack Drive — these adhesives are compatible with athermal coating.
5. Installation and fixation: Carefully lower the glass, secure with tape and leave for 12-24 hours to cure.

⚠️ Attention: If your car has a rain sensor or camera ADAS, additional calibration is required after glass replacement! Without it, driver assistance systems (Lane Assist, Adaptive Cruise Control) will not work correctly.

What happens if thermal glass is installed incorrectly?

Poor installation may result in:

- Water leaks into the interior (if the sealant is applied unevenly).

- Peeling of the coating (due to aggressive degreaser).

- Distortion of the view (if the glass was deformed during installation).

- False alarms of sensors (when the camera or sensors are displaced).

Caring for athermal glass: do's and don'ts

Athermal coating is sensitive to abrasives and chemicals. To avoid damaging it, follow the rules:

• ✅ Washing: Use soft sponges and ammonia-free shampoos (e.g. Sonax Glass Cleaner).
• ❌ Prohibited: Ice scrapers, hard brushes, products with acetone or alcohol.
• ⚠️ Caution: When cleaning rain sensors, do not rub the glass in this place - the coating is thinner!

To protect against scratches you can apply ceramic coating (for example, Ceramic Pro Glass), but only after consultation with the master - some compositions react with the metallized layer.

In winter:

• 🔥 Do not direct the flow of hot air from the stove directly onto the glass - a sharp temperature change can cause microcracks.
• ❄️ To remove ice, use special sprays (for example, Liqui Moly Anti-Ice), not a scraper.

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Athermal glass requires careful care - no abrasives or aggressive chemicals!

FAQ: Frequently asked questions about athermal glass

Is it possible to tint athermal glass?

Yes, but with reservations. The tint film is applied outside (on the outside of the glass) so as not to damage the athermal coating. Interior tinting may reduce the effectiveness of heat reflection. Also consider the law: light transmission must remain at least 70%.

How long does athermal glass last?

The service life depends on the quality of the coating and care. European brands (Sekurit, Pilkington) guarantee 10+ years without loss of properties. Cheap analogues can degrade after 3-5 years (stains appear, heat reflection decreases).

Does thermal exposure affect the operation of a radar detector or GPS?

No, if the glass is high quality. The metallized layer is too thin to shield radio waves. However, some owners Hyundai Solar and Kia They complain about a weak GPS signal - this is not due to the heat, but to the location of the antenna under the glass.

Can I apply athermal coating myself?

Theoretically yes, but in practice it is almost impossible. Industrial spraying occurs in a vacuum at high temperatures. "Spraying" from cans (for example, Nano-Ceramic) gives an effect of no more than 5-10% and wears off quickly. It is better to buy ready-made glass.

Is it true that cold weather impairs visibility at night?

Myth. High-quality athermal glass does not distort the view. However, cheap glass with a non-uniform coating can create glare from the headlights of oncoming cars. If you notice “light spots” - this is a defect, request a replacement under warranty.