Adler — THERMAL BREAK

A key to reduce heating and cooling energy consumption
Do you have any questions?
Ask us by filling out the form below
By submiting my data I agree to be contacted
Global warming is accelerating; weather conditions get extreme. Many countries are trying to reduce greenhouse emissions, along with country authorities are making strategic efforts to reduce energy consumption by applying enhanced insulation standards to new and renovated buildings, building zero-energy houses.

Aluminum glass facades bring light to the building; they are lightweight and highly durable. Furthermore, they can be excellently resistant to fluctuations in temperature and humidity if thermal insulation is effectively developed.

The thermal performance of the glass facades and windows is one of the factors that greatly influence the heating and cooling energy consumption of buildings.

Effective thermal insulation is a key factor when it comes to a comfortable and energy-efficient living environment.

Global warming is accelerating; weather conditions get extreme.  Country authorities are trying to reduce emissions and making strategic efforts to reduce energy consumption by applying enhanced insulation standards to new and renovated buildings.

The thermal performance of the glass facades and windows is one of the factors that greatly influence the heating and cooling energy consumption of buildings.
Effective thermal insulation is a key factor when it comes to a comfortable and energy-efficient living environment.
Thermal Insulation
Aluminium window and facade profiles are durable and resistant to any physical stress but unfortunately are highly heat conductive – which means easily transfer heat between the internal and external environment of a building.

Thermal insulation is the method of preventing heat transfer between objects in thermal contact. Its purpose is to reduce or even eliminate heat conduction between the internal and the outside environment of the building.

If the metal frames are not thermally separated, heat penetrates from the outside into the inside of the building and the opposite, consequently this results in high energy losses.

There is an isolation zone in thermally insulated windows which separate the highly conductive metal frames. It consists of various insulating components of windows which balance temperature fluctuations and influence the thermal performance of the window system in totality.
Thermal separation
So, what is heat: Heat is the form of energy that is transferred to or from thermodynamic systems or objects with different temperatures, heat always flows towards where the temperature is lower.

Heat transfer is generally described as including the mechanisms of heat conduction, heat convection, thermal radiation.

Thermal conduction: transfer of heat within a body or between two bodies in direct contact. No material is physically moved during this type of transfer.

Heat convection: transfer of heat between the surface of a solid, a liquid or a gas. This type of transfer involves movement via circulation, for instance, air circulation in a heated room.

Heat radiation: transfer of heat by radiation between two bodies at different temperatures.

The flow of heat can be greatly reduced through correspondingly optimised thermal insulation. For efficient insulation tailored to the particular requirements, the combination and fine adjustment of individual influential components in the insulation zone is required.

When designing aluminium systems, in order to reduce the thermal transmission coefficient of the highly conductive metal frame (Uf value), we need to separate the external aluminium profile from the internal one with a specific plastic barrier. This separation should be throughout the entire surface, not only at certain points. These insulating thermal barriers made from engineering plastics, for example ADLER Thermal Breaks, are inserted between the metal profiles and interrupt heat dissipation via aluminium. This is call thermal separation.
Through this separation, an insulation zone is integrated in the interior of the frame assembly.

The design engineer has a variety of options and material available, when designing this zone, for optimising the thermal insulation and bringing about a desired Uf value using construction measures.
Thermal break
Thermal break or insulating bar is an element of low thermal conductivity made of engineering polymer. It is placed between highly conductive aluminium frames to reduce or even prevent the flow of thermal energy. ADLER Thermal Break is made of Polyamide 66 has a heat transfer coefficient of 0,3/Wt and reinforced with glass-fibre for even better resistance to any physical impacts.

The application of polyamide 66 for thermal break strips:

  • Polyamide 66 has low thermal conductivity coefficient 0,3/Wt., which is 500 times lower than aluminium. However, it has thermal expansion coefficient similar to aluminium at the same time.

  • It has good resistance to high temperatures, which make it suitable for coating up to 200 C and allows the production of by-colour aluminium profiles.

  • It is highly resistant to ageing, corrosion and to the majority of chemical products like cleaning and processing agents.

  • Polyamide thermal breaks do not emit salt acid gases in case of fire, the residues produced from burning lack toxicity and are not harmful to the atmosphere.

  • Foremost this material is recyclable and environmentally friendly.

The reduction of wall thicknesses and increase in insulation depths of these insulating profiles are further possibilities for keeping the heat transfer through transmission at a low level. ADLER Thermal Breaks can be produced with wall thickness up to 1 mm which allows heat transfer coefficient to comply with stringent technical requirements.

A reduction in the size of the hollow chambers within the insulation zone minimises air circulation. Profile shapes with hollow chambers or geometries with flags generate such smaller convection cells.

The range of ADLER Thermal Breaks consist of different shapes and insulation depths, and a variety of system groups of geometries with different elements for required function zones. They are made of solid polyamide 66 and reinforced with glass-fiber, consequently they are the right choice in terms of functionality and cost-efficiency.
How to evaluate the thermal performance of a window?
Thermal performance of a window refers to the heat transfer between the metal window and space it is in. It is an approximate rate that is concerned with how well a system responds to heat flow between the outdoor and indoor environment.

Thermal performance measured in terms of heat loss. The U-value is a measurement of heat loss.

The U-value for the whole window (Uw) combines: the U-value for the window frame (Uf) and the U-value for glass (Ug).

Uw-coefficient shows the flow of heat through the window in W / m2K. For every Kelvin heat difference and every m2, this much (Watt) heat transfers through the window. The lower the number, the better the insulating performance of the window and the less energy needed to heat or cool the interior.

The Uf-value depends on:

  • Design of the frame profile

  • The material used

  • The type of insulation zone

  • The insulation depth and number of chambers in the profile and the type of thermal break used.
Combining the Uf- and Ug-values will give a Uw-value which is a measure of heat loss for the whole window or façade system.

There are various tests to measure the thermal performance for window and doors systems, but the best way to measure it is by using either the guarded hot box or calibrated hot box method.
How to decrease Uw coefficient or How to improve thermal insulation of the window system
Heat isolation technologies for aluminium facades have seen various improvements from multilayer glass to argon gas, PVC spacer, and etc. Certainly, all components of the metal window system play an important role in the improvement of system heat transmission, but since aluminium has the highest heat transfer coefficient of all of the components it needs to be minimised.

To improve the thermal performance of the whole window system and to achieve a more favourable thermal transmission coefficient (Uw value) we need to decrease the Uf value of the window frame at first.

As we said above, The Uf-value depends on the design of the frame profile, the number of chambers in the profile, the technical characteristics of chosen isolation components and its elements.

To reduce the heat transfer coefficient of the metal frame (Uf value) where aluminium has high thermal conductivity λ = 160 W / (m )K), we separate the external aluminium shell from the internal one by inserting a low conductive polyamide Thermal Break which cut the thermal bridges perpendicular to the heat flow direction, as a result, direct heat dissipation via the aluminium is interrupted.

The conductivity of thermal breaks measures lambda value in units of W/mK. If lambda is lower, heat transfer due to conduction gets lower. Lambda of ADLER thermal barriers which are made of special thermoplastics with a thermal conductivity as low as λ = 0.3 W/(mK)
The thickness of the walls and depth of the thermal break profile are other factors to decrease heat transfer due to conduction. Thicker profiles conduct more. ADLER Thermal Breaks wall thickness can be produced down to 1 mm.

On our standard catalogue, we have various profiles with a depth of 14.8mm to 57 mm, they correspond to insulation depth when combined with aluminium profiles. The bigger the ADLER thermal break profiles, the more energy and costs can be saved.
Benefits of Polyamide Thermal Break
  • Low thermal conductivity coefficient, 500 times lower than aluminium.

  • A thermal expansion coefficient is similar to aluminium.

  • Good resistance to high temperatures. Suitable for coating (up to 200°C) which allows the production of by-colour aluminium profiles.

  • Resistant to physical impact, to ageing and corrosion, thanks to the 25% glass fiber content.

  • Resistant to UV radiation due to its black carbon content and the polymer intrinsic properties and the process method.

  • Resistant to the majority of chemical products, cleaning and processing agents.

  • Polyamide profiles do not expose salt acid gases in case of fire. The residues produced from burning lack toxicity and neither are they harmful to the atmosphere.

  • Fewer draughts and no chill sensation close to windows, savings on heating and air conditioning costs. It also prevents condensation and mould.

  • Comply with statutory energy-saving requirements and carbon emissions.

  • Recyclable. Environmentally friendly
Thermal Insulation
Aluminium window and facade profiles are durable and resistant to any physical stress but unfortunately are highly heat conductive – which means easily transfer heat between the internal and external environment of a building.

Thermal insulation is the method of preventing heat transfer between objects in thermal contact. Its purpose is to reduce or even eliminate heat conduction between the internal and the outside environment of the building.

If the metal frames are not thermally separated, heat penetrates from the outside into the inside of the building and the opposite, consequently this results in high energy losses.

There is an isolation zone in thermally insulated windows which separate the highly conductive metal frames. It consists of various insulating components of windows which balance temperature fluctuations and influence the thermal performance of the window system in totality.
Thermal separation
So, what is heat: Heat is the form of energy that is transferred to or from thermodynamic systems or objects with different temperatures, heat always flows towards where the temperature is lower.

Heat transfer is generally described as including the mechanisms of heat conduction, heat convection, thermal radiation.

Thermal conduction: transfer of heat within a body or between two bodies in direct contact. No material is physically moved during this type of transfer.

Heat convection: transfer of heat between the surface of a solid, a liquid or a gas. This type of transfer involves movement via circulation, for instance, air circulation in a heated room.

Heat radiation: transfer of heat by radiation between two bodies at different temperatures.

The flow of heat can be greatly reduced through correspondingly optimised thermal insulation. For efficient insulation tailored to the particular requirements, the combination and fine adjustment of individual influential components in the insulation zone is required.

When designing aluminium systems, in order to reduce the thermal transmission coefficient of the highly conductive metal frame (Uf value), we need to separate the external aluminium profile from the internal one with a specific plastic barrier. This separation should be throughout the entire surface, not only at certain points. These insulating thermal barriers made from engineering plastics, for example ADLER Thermal Breaks, are inserted between the metal profiles and interrupt heat dissipation via aluminium. This is call thermal separation.
Through this separation, an insulation zone is integrated in the interior of the frame assembly.

The design engineer has a variety of options and material available, when designing this zone, for optimising the thermal insulation and bringing about a desired Uf value using construction measures.
Thermal break
Thermal break or insulating bar is an element of low thermal conductivity made of engineering polymer. It is placed between highly conductive aluminium frames to reduce or even prevent the flow of thermal energy. ADLER Thermal Break is made of Polyamide 66 has a heat transfer coefficient of 0,3/Wt and reinforced with glass-fibre for even better resistance to any physical impacts.

The application of polyamide 66 for thermal break strips:
  • Polyamide 66 has low thermal conductivity coefficient 0,3/Wt., which is 500 times lower than aluminium. However, it has thermal expansion coefficient similar to aluminium at the same time.
  • It has good resistance to high temperatures, which make it suitable for coating up to 200 C and allows the production of by-colour aluminium profiles.
  • It is highly resistant to ageing, corrosion and to the majority of chemical products like cleaning and processing agents.
  • Polyamide thermal breaks do not emit salt acid gases in case of fire, the residues produced from burning lack toxicity and are not harmful to the atmosphere.
  • Foremost this material is recyclable and environmentally friendly.

The reduction of wall thicknesses and increase in insulation depths of these insulating profiles are further possibilities for keeping the heat transfer through transmission at a low level. ADLER Thermal Breaks can be produced with wall thickness up to 1 mm which allows heat transfer coefficient to comply with stringent technical requirements.

A reduction in the size of the hollow chambers within the insulation zone minimises air circulation. Profile shapes with hollow chambers or geometries with flags generate such smaller convection cells.

The range of ADLER Thermal Breaks consist of different shapes and insulation depths, and a variety of system groups of geometries with different elements for required function zones. They are made of solid polyamide 66 and reinforced with glass-fiber, consequently they are the right choice in terms of functionality and cost-efficiency.
How to evaluate the thermal performance of a window?
Thermal performance of a window refers to the heat transfer between the metal window and space it is in. It is an approximate rate that is concerned with how well a system responds to heat flow between the outdoor and indoor environment.

Thermal performance measured in terms of heat loss. The U-value is a measurement of heat loss.

The U-value for the whole window (Uw) combines: the U-value for the window frame (Uf) and the U-value for glass (Ug).

Uw-coefficient shows the flow of heat through the window in W / m2K. For every Kelvin heat difference and every m2, this much (Watt) heat transfers through the window. The lower the number, the better the insulating performance of the window and the less energy needed to heat or cool the interior.

The Uf-value depends on:

  • Design of the frame profile
  • The material used
  • The type of insulation zone
  • The insulation depth and number of chambers in the profile and the type of thermal break used.
Combining the Uf- and Ug-values will give a Uw-value which is a measure of heat loss for the whole window or façade system.

There are various tests to measure the thermal performance for window and doors systems, but the best way to measure it is by using either the guarded hot box or calibrated hot box method.
How to decrease Uw coefficient
Heat isolation technologies for aluminium facades have seen various improvements from multilayer glass to argon gas, PVC spacer, and etc. Certainly, all components of the metal window system play an important role in the improvement of system heat transmission, but since aluminium has the highest heat transfer coefficient of all of the components it needs to be minimised.

To improve the thermal performance of the whole window system and to achieve a more favourable thermal transmission coefficient (Uw value) we need to decrease the Uf value of the window frame at first.

As we said above, The Uf-value depends on the design of the frame profile, the number of chambers in the profile, the technical characteristics of chosen isolation components and its elements.

To reduce the heat transfer coefficient of the metal frame (Uf value) where aluminium has high thermal conductivity λ = 160 W / (m )K), we separate the external aluminium shell from the internal one by inserting a low conductive polyamide Thermal Break which cut the thermal bridges perpendicular to the heat flow direction, as a result, direct heat dissipation via the aluminium is interrupted.

The conductivity of thermal breaks measures lambda value in units of W/mK. If lambda is lower, heat transfer due to conduction gets lower. Lambda of ADLER thermal barriers which are made of special thermoplastics with a thermal conductivity as low as λ = 0.3 W/(mK)
The thickness of the walls and depth of the thermal break profile are other factors to decrease heat transfer due to conduction. Thicker profiles conduct more. ADLER Thermal Breaks wall thickness can be produced down to 1 mm.

On our standard catalogue, we have various profiles with a depth of 14.8mm to 57 mm, they correspond to insulation depth when combined with aluminium profiles. The bigger the ADLER thermal break profiles, the more energy and costs can be saved.
Benefits of Polyamide Thermal Break
  • Low thermal conductivity coefficient, 500 times lower than aluminium.
  • A thermal expansion coefficient is similar to aluminium.
  • Good resistance to high temperatures. Suitable for coating.
  • Resistant to physical impact, to ageing and corrosion.
  • Resistant to UV radiation.
  • Resistant to the majority of chemical products.
  • Do not expose salt acid gases in case of fire.
  • Fewer draughts and no chill sensation, also prevents condensation and mould.
  • Comply with statutory energy-saving requirements and carbon emissions.
  • Recyclable. Environmentally friendly.
Blistering and foaming on the insulating strips
Polyamide is a hydrophilic thermoplastic which absorbs moisture from the environment over time. The humidity intake is a property of the material; it is normal and unavoidable. However, the rate and degree of moisture-absorption are dependent on the ambient temperature and ambient humidity.

The humidity equilibrium at 23°C and 50% is around 2%. If the profiles are stored in a hot and/or humid area, humidity uptake is more than 2% and this increases the probability to see bubbles during coating.

In the case where the polyamide thermal break profile is subjected to high temperatures after having absorbed moisture (and if it especially has more than 2% relative humidity), this moisture is converted into the vapour phase. This change of state is accompanied by an increase in volume, which can result in blistering or foaming of the insulating strip.

To prevent blistering and foaming of ADLER thermal break profiles, please ensure the following:

  • Dry storage of insulating strips

  • Rigorous drainage of composite insulated profiles during coating and anodization

  • The uniform temperature in drying and baking ovens.
The importance of good knurling and assembly
Assembling of ADLER insulating profiles in aluminium profiles

Assembly should be carried out under room temperature and normal humidity levels. The stages of assembling insulated aluminium window profile are as follows: Knurling, insertion and pressing (curling, crimping, rolling)

The importance of the knurling of the aluminium profile cavity.

In order to achieve a quality assembly with great mechanical features, a professionally executed knurling is vital. Both noses of the aluminium cavity should have been knurled sufficiently. Then ADLER thermal break profile is inserted, the pressing wheel presses the jagged noses into our plastic insulating profile. As a result of the pressure, the teeth of the knurled edge ‘bite’ deeply into the ADLER thermal insulating profile on both sides. The hammer must penetrate to the foot of the insulating strip.

The assembly produced in this way must be able to withstand diverse stresses over a long period. For example, withstanding the high temperature during powder coating or later, the stresses resulting from heat and cold. TS EN 14024 lays down the minimum requirement relating to the shear strength of these frame assemblies.

  • The effect brought about by sharp-toothed knurling makes a crucial contribution to the long-lasting high shear strength of the assembly. Inadequate knurling occurs as a result of a worn knurling wheel, keep in mind to change it if needed.