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

In the summer, the car interior turns into a hot furnace, and in the winter the windows become covered with ice? Athermal glazing - a solution that will help maintain a comfortable temperature in the car without extra costs for air conditioning or heating. But what is it really and how does it work?

Many people confuse athermal film with conventional tinting, but these are fundamentally different technologies. If tinting simply darkens the glass, then athermal coating blocks up to 99% of ultraviolet radiation and reduces thermal conductivity without affecting light transmission. This means that the cabin will be cooler, and the view will remain as clear as with conventional glass.

Today, athermal glass is installed even on budget models - for example, on Lada Vesta or Kia Rio, but not everyone knows how to choose and operate such glazing correctly. In this article we will look at what types of athermal glass there are, how they work and what to look for when purchasing.

What is athermal glazing and how does it work?

The term “athermal” comes from the Greek “athermos” - “not heated”. In the automotive industry, this means that glass absorb or reflect infrared radiation, which is responsible for heating the interior. In this case, visible light passes through practically without distortion.

The operating principle is based on a multilayer structure of glass or special film:

1. The outer layer is usually tempered glass, resistant to mechanical damage.
2. The inner layer is a metallized or ceramic layer that reflects IR rays.
3. Protective coating - prevents scratches and extends service life.

Unlike conventional tinting, athermal coating does not obscure the view (if light transmission standards are met). For example, glass with an athermal effect can have light transmittance up to 70-80%, while even light tinting reduces this figure to 50-60%.

Interesting fact: the first athermal glass appeared in aviation, where it was necessary to protect pilots from overheating in the cockpit. Later the technology was adapted for cars, and today it is used even in premium models Mercedes-Benz and BMW.

Types of athermal glazing: factory vs. film

There are two types of athermal glazing: factory (set by the manufacturer) and film (pasted separately). Each option has its pros and cons.

Factory athermal glass built into the car at the production stage. They are a multilayer structure, where between the layers of glass there is a metallized or ceramic layer. These glasses:

• 🔹 They last longer (the service life is equal to the service life of the car).
• 🔹 Does not require additional care.
• 🔹 Meets all safety standards.
• 🔹 More expensive to repair (if damaged, the entire glass needs to be replaced).

Athermal film - a more budget option. It is glued to already installed glass. Modern films (for example, LLumar Air 80 or 3M Crystalline) are practically not inferior to factory glass in terms of efficiency, but:

• 🔹 Can be installed on any car, even if the factory did not provide athermal glazing.
• 🔹 Cheaper to replace (if damaged, only the film is replaced).
• 🔹 Requires professional stickers - errors may cause bubbles or peeling.
• 🔹 Service life - 5-10 years (depending on the quality of the material).

Important: Not all films are equally effective. Cheap analogues can not only provide poor protection from heat, but also impair visibility, especially in the dark.

How to distinguish real athermal glass from a fake?

Real athermal glass, when viewed under direct sunlight, has a slight greenish or bluish tint (due to the metallized layer). If the glass is simply darkened, but does not reflect heat, this is ordinary tinting. You can also check with an IR thermometer: athermal glass heats up much more slowly than usual.

Advantages of athermal glazing: why is it beneficial?

The main advantage of athermal glass is reducing the temperature in the cabin by 10-15°C compared to conventional glass. But this is not the only plus. Let's take a closer look at all the advantages.

1. Saving fuel and air conditioner life

When the interior doesn't get as hot, the air conditioning turns on less often. This means:

• 🔋 Less fuel consumption (the air conditioner “eats” up to 10% of the engine power).
• ❄️ Extending the service life of the climate system.
• 💰 Savings on freon refills and compressor repairs.

2. Protection of the interior and passengers from UV radiation

Ultraviolet radiation not only causes skin burns, but also destroys interior materials:

• 🪑 Prevents fading of seat upholstery and instrument panels.
• 🧴 Reduces the risk of skin cancer during long trips.
• 👓 Protects eyes from fatigue (UV rays cause irritation of the cornea).

3. Safety and comfort

• 🚗 Less glare from the sun - improved visibility.
• ❄️ In winter, the glass fogs up less and becomes covered with ice.
• 🔇 The noise level is reduced (multi-layer glass absorbs sound better).

4. Compliance with the law

Unlike tinting, athermal glass do not violate the requirements of GOST R 51709-2001, if their light transmission is not lower than 70% for the windshield and front side windows. This means that they can be used without the risk of a fine.

Athermal glass reduces the load on the engine cooling system, as the interior heats up more slowly, which means less heat is transferred to the engine compartment through the partition.

Disadvantages and myths about athermal glazing

Despite the obvious advantages, this technology also has disadvantages. In addition, there are many myths surrounding athermal glass that are worth debunking.

Real disadvantages:

• 💸 High cost (factory athermal glass can cost 2-3 times more than regular glass).
• 🔧 Difficulty of repair (if there is a crack, you will have to replace the entire glass, not just the film).
• 📉 Slight degradation of GPS and mobile communications signals (due to the metallized layer).

Common myths:

• ❌ “Athermal glass completely blocks heat” - in fact, they reduce heat, but do not eliminate it completely.
• ❌ “Such glass does not break” - they are stronger than ordinary glass, but not invulnerable.
• ❌ “Athermal film spoils glass” - high-quality film does not harm if it is glued correctly.

⚠️ Attention: Cheap athermal films can yellow or peel over time, reducing visibility. Always check quality certificates before purchasing.

One more nuance: if you install athermal film on the windshield, you may get a fine, if its light transmission is below 70%. Therefore, for front windows it is better to choose the most transparent options.

How to choose athermal glazing: expert advice

If you decide to install athermal glass or film, pay attention to the following parameters:

1. Glazing type

Criterion	Factory glass	Athermal film
Service life	For the entire life of the car	5-10 years
Cost	High (from RUB 15,000 per glass)	Medium (from RUB 3,000 per set)
Installation	Only at the service station	Can be pasted by yourself
Efficiency	Higher (up to 99% UV protection)	Below (up to 95% UV protection)

2. Light transmission

For windshield and front side windows, choose a film with light transmission at least 70%. For rear windows you can use darker options (up to 35%).

3. Film material

• 🔹 Metallized - cheaper, but can degrade the communication signal.
• 🔹 Ceramic - more expensive, but do not affect radio and GPS.
• 🔹 Hybrid - gold standard (combines the advantages of both types).

4. Brand and certificates

Give preference to trusted manufacturers:

• 🏆 3M (series Crystalline, Scotchtint)
• 🏆 LLumar (series Air, ATR)
• 🏆 Solar Gard (series Quantum)
• 🏆 Johnson Window Films (series InsulatIR)

⚠️ Attention: Before purchasing, check whether the film has a certificate of conformity GOST R 51709-2001. Without it, the film may be prohibited for use.

Ensure light transmittance ≥70% for front windows|

Check for a quality certificate |

Choose a film with a guarantee of at least 5 years|

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Installing athermal film: step-by-step instructions

If you decide to apply the film yourself, follow these instructions. To work you will need:

• 🔹 Athermal film (with a margin in size).
• 🔹 Spray bottle with soap solution (10 drops of shampoo per 1 liter of water).
• 🔹 Rubber spatula (squeegee).
• 🔹 Knife or stationery cutter.
• 🔹 Hair dryer (to smooth out bubbles).

Step 1: Preparing the Glass

Wash the glass thoroughly on both sides, remove grease and dust. Wipe the surface with a lint-free cloth.

Step 2: Film pattern

Apply the film to the outside of the glass and cut along the contour, leaving a margin of 1-2 cm. For curved glass (for example, rear glass), use the “wet” cutting method: spray the glass with soapy water, apply the film and cut to shape.

Step 3: Sticker

1. Spray the glass and the adhesive side of the film with soapy water.
2. Carefully apply the film to the glass, starting from the top edge.
3. Using a squeegee, smooth out from the center to the edges, removing bubbles and excess water.
4. Heat the film with a hairdryer (temperature 50-60°C) for a better fit.

Step 4: Finishing

Trim excess film around the edges of the glass. Do not wash the car for 3-5 days to allow the glue to dry completely.

⚠️ Attention: If small bubbles remain after the sticker, do not try to squeeze them out - they will disappear on their own in 1-2 weeks. Large bubbles mean that the film will have to be re-taped.

Comparison of athermal glazing with other methods of sun protection

Athermal glass is not the only way to reduce the temperature in the cabin. Let's look at the alternatives and compare their effectiveness.

1. Regular tinting

• ✅ Cheaper than athermal film.
• ❌ Darkens the view, may be prohibited by law.
• ❌ Does not block UV rays and infrared radiation.

2. Curtains and blinds on glass

• ✅ You can install it yourself.
• ❌ They block the view and are inconvenient to use.
• ❌ They do not protect against heat when the car is standing in the sun.

3. Sunscreen on the windshield

• ✅ Effectively reduces temperature.
• ❌ Requires installation before each parking lot.
• ❌ Does not protect side windows.

4. Climate control and air conditioning

• ✅ Quickly cools the interior.
• ❌ Increases fuel consumption.
• ❌ Requires regular maintenance.

Efficiency comparison table:

Method	Temperature reduction	UV protection	Cost	Convenience
Athermal glazing	⭐⭐⭐⭐⭐	⭐⭐⭐⭐⭐	$$$	⭐⭐⭐⭐⭐
Tinting	⭐⭐	⭐	$	⭐⭐⭐
Curtains/blinds	⭐⭐⭐	⭐⭐	$	⭐
Sunscreen	⭐⭐⭐⭐	⭐⭐⭐	$	⭐⭐

FAQ: Frequently asked questions about athermal glazing

Is it possible to stick athermal film on tint?

No, this will lead to a deterioration in light transmission and may result in a fine. If there is already tinting on the glass, it must be removed first.

How much does it cost to replace a windshield with a thermal one?

The cost depends on the car model and type of glass. On average:

• Budget cars (Lada, Renault) - from 15,000 ₽.
• Middle class (Toyota, Hyundai) - from 25,000 ₽.
• Premium (Audi, BMW) - from 40,000 ₽.

Does athermal film affect the operation of the radar detector?

Metallized films may degrade the signal, but ceramic or hybrid options (e.g. 3M Crystalline) do not affect the operation of the radar detector.

Is it possible to wash athermal glass with conventional means?

Yes, but in the first 3-5 days after gluing the film, it is better to use only water and a soft cloth. Later, you can use any car detergents without abrasives.

Is it true that athermal glass warms the interior worse in winter?

No, it's a myth. Athermal glass only blocks infrared radiation (heat from the sun), but does not interfere with the operation of the stove or glass heating.