Thermal insulation: a basic requirement combined with our security performances
In an era of growing environmental awareness and the fight against climate change, the energy efficiency of buildings has become a priority for businesses, institutions, and individuals. In most European countries, it is even a legal requirement. Proper thermal insulation of joinery (doors, windows, glazed partitions) helps reduce heat loss, improve indoor comfort, and lower energy consumption.
Standards EN 10077-1 and EN 10077-2 define the methods for assessing the thermal performance of joinery. These are essential to ensure compliance with current regulations and to select products that meet the thermal requirements of construction and renovation projects. We naturally offer thermal insulation as a comfort feature that can be combined with our security performances such as burglary resistance, bullet resistance, fire protection, detention-grade solutions, and more.
Thermal insulation of joinery: understanding standards EN 10077-1 and EN 10077-2
The main objective of these European standards is to determine the thermal transmittance coefficient Uw (W/m²·K), which measures the ability of a joinery element to limit heat loss.
- EN 10077-1 specifies the calculation method for the thermal transmittance of doors and windows.
- EN 10077-2 describes numerical simulation methods for a more precise assessment of thermal performance.
The lower the Uw value, the better the thermal insulation.
Calculation method according to EN 10077-1
Joinery is classified based on its thermal insulation capacity:
The European standards EN 10077-1 and EN 10077-2 establish a classification in seven classes, labeled from T0 to T6, based on the Uw values (overall thermal transmittance coefficient) of the elements. Here are the classes and their corresponding values:
Tests and simulations assess the overall thermal performance of joinery, taking into account several elements:
- the frame (Uf): thermal transmittance coefficient of the structural material
- the frame surface area (Af)
- the glazing (Ug): thermal insulation performance of the glass
- the glazing surface area (Ag)
- the linear thermal bridge coefficient (Ψg): heat losses at the spacers between glazing and frame
- the visible glazing perimeter (Lg)
The final result is expressed by the Uw coefficient, which is calculated using the following formula:
Classification of the thermal performance of joinery
| Class | T0 | T1 | T2 | T3 | T4 | T5 | T6 |
|---|---|---|---|---|---|---|---|
|
Value Uw (W/m²K) |
> 3,5 |
≤ 3,5 |
≤ 3,0 |
≤ 2,5 |
≤ 2,0 |
≤ 1,5 |
≤ 1,0 |
It is important to note that, depending on local regulations, minimum requirements may be imposed.
Factors influencing the thermal performance of joinery
The thermal insulation of a door or window depends on several combined factors for an optimal result:
- Frame material and profile type: steel or aluminium with thermal break
- Glazing type: double or triple glazing with argon or krypton gas
- Sealing gaskets: limiting air leaks for better insulation
- Spacer quality: materials with low thermal conductivity
- Proper installation: to avoid thermal bridges
The importance of high-performance thermal joinery
The thermal insulation of doors and windows is essential to:
- Reduce energy costs
- Improve the thermal comfort of occupants
- Ensure compliance with environmental standards
Are you an architect or a design office?
We support you in selecting suitable thermal solutions.
Are you a general contractor or installer?
Our joinery is compliant and ready to be installed.
