Thermal and sound insulation are top criteria in the selection of aluminium frames because they upgrade buildings, improve the quality of life of the users and contribute to the protection of the environment.
Thermal Transmittance
Thermal transmittance defines how easily heat (measured in watts) passes through a material of a certain thickness and area of one square meter in one hour. It should be remembered that the flow of heat is always in the direction from the hottest to the coolest. In winter, heat escapes from the interior to the colder exterior, while in summer the heat is directed towards the interior of buildings. The coefficient of thermal transmittance determines the thermal insulation capacity of the building element and gives the amount of heat that is transferred.
An aluminium energy system owes its thermal insulation to the thermal break. The thermal break is the interference between the inner and outer aluminium profile, a material that is a poor conductor of heat, and is achieved by using polyamide, an insulating material that also contributes to the robustness of the frames. It is applied as a barrier to the cross-section of the profile and is essentially a thermoplastic resin. What it does in practice is to interrupt the transmission of external temperature to the inside of the window frames, as it is a poor conductor of heat. This reduces pollutants, heating and cooling operating costs.
Two important factors that have a catalytic effect on minimizing heat loss are the glazing type as well as the aluminium frame.
Type of glazing:
- Heat losses due to transmission are directly related to the surface area, so the glazing, which represents the largest part (70% – 80%) of a frame, plays an important role in the estimation of heat losses.
- Thermal insulation achieved by the glazing of the frame depends primarily on the gap between them. The thicker the glazing, the higher the sound and heat insulation as well as the security you will have.
- Additionally, in terms of safety and sound insulation, you can choose between triplex (laminated) and securit (tempered) glazing or glazing that combines both technologies (such as automotive glazing).
Type of aluminium frame
- We have heat losses not only through the glass, but also through the frame of the system. Therefore, a system with lower thermal conductivity will reduce losses through the frame. Heat transfer stops when the temperatures of the materials are equalized. This is called thermal equilibrium. The heat transferred to a material depends on its mass, its type, and the change in its temperature.
- The aim of thermal insulation materials in a building is to reduce the heat flow between materials or spaces that are at different temperatures. Thermal insulation reduces heat transfer by conduction or radiation by blocking or reflecting rather than absorbing energy.
Soundproofing
The annoyance caused by external noise degrades the quality of life and has a negative impact on health, living and communication. It is significant that the World Health Organization considers noise pollution to be the second most important environmental health risk.
Sound insulation is an important factor in the choice of frames. A frame with the appropriate sound insulation class effectively reduces the noise level within homes or workplaces.
The most important part that contributes to sound insulation is the glass pane because it occupies the largest surface area of the entire frame. Of course, in proportion to its area, the frame of the system also plays its role in the overall sound insulation.
Acoustic insulation should be one of the main features that aluminium systems should have to meet modern requirements for avoiding noise transmitted through the air.
To meet the above requirements, doors and windows should meet at least the following properties:
- Good air resistance
- High stress resistance
- Glazing and rubbers shall be of suitable materials and thicknesses.
- The assembly of the frame, but also the installation in the building to have a very good fit
Unlike thermal insulation, the sound insulation achieved does not depend on whether the glazing is double, triple, etc., but on the thickness of the glazing. Increasing the thickness of the glass pane improves the sound insulation.