Outstanding Quality


Outstanding Quality

Better Quality, Higher Safety

TOSTEM is committed to developing the best products to meet customers’ requirements. Detailed inspections are carried out during design and testing stages to assess criteria such as basic performance, durability, weather resistance, and such. Only designs that pass strict quality-control tests are made into products for delivery to customers.

TOSTEM windows are thoroughly tested on all basic performance parameters such as:

Why performance is importance to us?

TOSTEM windows undergo a variety of other tests which increase the overall reliability and hence the value of the window. Some of these tests include:

  • Opening-closing durability tests
  • Strength tests
  • Sound insulation tests
  • Thermal insulation tests
  • Light exposure tests (UV resistance performance)
  • Environmental tests
  • Surface treatment tests

TOSTEM Performance Assurance

Wind Loading Resistance Performance

It indicates the pressure of wind which the window can sustain safely. The purpose is to ensure that the selected windows can resist a level wind load in area height without any loss, cracking or breakage.

When the wind blows is blowing, it generates pressure (Wind pressure) against the surface of any structure obstructing its movement. The intensity of this pressure is the wind load. The unit of measurement of wind load is Pascal (Pa).

Here is a quick reference relating wind speed to wind load and its effect.

*TOSTEM products have a wind resistance range of 800 Pascal to 2000 Pascal.

Water Tightness Performance

It indicates the rate of pressure at which a window can prevent the infiltration of water into a room. The purpose is to help select a watertight window that can prevent interior damage due to water intrusion into a room.

During the Indian monsoon, when there is rainfall along with heavy winds, water tends to experience blow-back from the conventional windows with no or badly designed drainage system.

*TOSTEM windows have the range to resist the water with heavy winds pressure of 150 Pascal to 300 Pascal.

Air Tightness Performance

It indicates how much air can pass through the gaps between the frame and the panels. The purpose is to evaluate the air coming into a room from outside.

When we use a window that stops air leakage, we prevent the intrusion of dust inside the home: the efficiency of the air conditioning unit improves and the sound insulation property of the window also improves drastically.

*TOSTEM windows have been tested to perform a permissible air leak of 8 m3/m2/hour to 10.7 m3/m2/hour.

Noise Insulation Performance

It indicates the level of sound blocked out from outside to the inside of the room. The purpose is to measure the level of sound that can be insulated by a window.

Sound insulation is very perceptive and varies among individuals. A sound can be harsh to someone and pleasant to others. Also, it is said that when the sound level is reduced by 10db, people feel that the noise level is halved.

*TOSTEM windows can help reduce the sound by 25 Decibels with 6 MM single glass, and this insulation level can further improve with the increased glass thickness.

Apart from the above, TOSTEM windows assure performance on other secondary indicators, like:

Resist rusting and irregular fading under environmental conditions.

It indicates the resistance of products to adverse effects of various climatic conditions such as moisture, dust, sunlight and pollution. Rainfall in coastal areas is saline in nature which can corrode many metals much faster than what happens in dry climate. Also, heavy air pollution turns the mist and fog(smog) into light acid which can react with surfaces and cause blemishes and fading.

Operate easily under standard conditions

As the panel size and glass thickness increases, the panels gains weight and hence become more and more difficult to use. At TOSTEM, we test our product so that it should be easy to operate for everyone residing in the house be it a young child or the old age person. All our windows are tested so as to take less than 5Kgs of force to operate in standard sizes.

Better air & water sealing!

Japanese windows are designed for far better performance against air and water which is very important for comfortable living. This is achieved by:

  • Rubber gaskets are used instead of wool-pile. This provides better sealing against dust, noise, and water.
  • Gaskets help in the smooth operation of the window and have a longer life.
  • Precision nano-tech gaskets are used at frame corner joints to stop water ingress. It is not necessary to fill joints with silicon which is common practice with traditional windows.
  • Water entry is stopped through the use of a one-way drainage valve. Also, the frame is designed to create a water-head between inside & outside. Using a common rule of thumb, wind pressure up to 10 times of water head can be sustained without the entry of water inside.


The TOSTEM window is very unique as the section thickness is higher in the transverse direction to sustain higher wind load. Also, the thickness is higher at points of screw fixing. The aluminum alloy used is 6063 with T5 tempering which has more strength. The corner is joined at 90º and does not require cleats, which are less strong. The TOSTEM window is stronger and has a longer performance life as compared to other window materials.

Designing into Every Details

L-Fit is a handle design that “fits” in with “living life.” This standardized design for the handles of windows and entrance doors creates a sense of uniformity and comfort in living space.

Greater safety with crescent lock

A crescent lock is sturdier and far safer as compared to a push lock. It can only be locked in one position and it is easy for the user to see if the lock is in place. A secondary lock stops crescent lock from inadvertently getting opened.

*Performance parameters will depend upon the size and design of the window.

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