Calculated coefficients: Uw, Ro, Rw, Sw, SHGC and LT

The Uw heat transfer coefficient is the key indicator of the thermal insulation of the windows you produce. It is a value that directly affects the energy efficiency of the structure - a lower Uw value means better insulation properties. Stolcad^® Professional precisely calculates this coefficient using a standardized formula and user-defined data. The results of the calculations of the Uw coefficient for windows and doors are automatically inserted in the prepared offers.

For users with the additional modules, these values can also be included in documents such as declarations of performance, energy passports, or finished product labels. The module not only provides precise calculations but also allows for easy sharing and presentation, which is the key element of offering for the window industry.

The Ro coefficient, also known as the Ro norm of windows, refers to the heat transfer indicator through windows, which is expressed in thermal resistance values. It is a measure of a material's ability to resist heat flow. The higher the Ro value,

the better the thermal insulation of the window, which means less heat loss from the room to the surroundings. Standards for the Ro coefficient may vary depending on national or regional regulations and are significant in assessing the energy efficiency of buildings.

The average Uw factor for an order can be calculated when dealing with the supply of different types of windows for one project. In such cases, each window (or group of windows with the same parameters) has its individual Uw factor. The average Uw factor for the entire order (project) is calculated as a weighted average of these individual values, where the weights are the surfaces of the individual windows. Information about the calculated average Uw factor is then placed in the offer summary or another designated place.

The extension offers a precise calculation of the Rw factor, which is the key indicator determining the level of sound absorption of the window construction. With this module, you can provide clients with detailed information about the acoustic properties of the windows being designed, enabling them to choose a product that best meets their acoustic needs. In this process, the user of the software first manually enters data about the glass characteristics, which are based on technical specifications provided by the glass manufacturer. Then, the module automatically calculates the level of sound absorption for the window constructions, taking into account the changing sizes of the

window surfaces during the design. Dynamic adjustment of the Rw factor value, depending on the sizes of the constructions selected by the user, guarantees the achievement of ideal acoustic properties that fully meet the expectations of customers. The result of the Rw factor calculations is automatically included in the prepared offers. For users with additional modules, there is an option to place this data also on declarations of performance or finished product labels. Such action significantly facilitates the presentation of the product, enabling efficient sharing of the key information.

This module allows for the precise calculation of the solar factor Sw of windows, also known as the solar light transmission coefficient. This important parameter reflects the ability of a window to transmit solar energy into a building, directly affecting the energy efficiency of the structure, its natural lighting, and the thermal comfort of the residents. The Sw value depends on many factors, including the thermal insulation parameters of the entire window structure, i.e. the Uw factor, as well as the insulation of the glass itself. The general rule is that the more solar heat is transmitted through a window, the higher the Sw factor.

The colour of window profiles is also crucial. Darker profiles heat up faster under the influence of solar rays, resulting in a bigger heat transfer to the interior. Windows characterized by a high Sw factor can help reduce heating costs in the winter season by utilizing solar heat. However, in the summer they can also lead to unwanted increases in indoor temperatures, which in turn increases the need for cooling rooms. Therefore, it is important that the selection of the Sw value is closely adapted to the climate of the region where the building is located and to its orientation relative to the cardinal directions.

Different requirements are typically set for light transmittance for windows installed on opposite sides of buildings. For this purpose the Light Transmittance (LT) coefficient is commonly used. It represents in percentage how much natural light passes through the glass into the interior. This parameter largely depends on the thickness of the glass and the type of material.

On the US market, the commonly used coefficient related to light is SHGC (Solar Heat Gain Coefficient). The module allows entering the SHGC values. This coefficient reflects the efficiency of a window in terms of the amount of solar heat and sunlight that passes into the interior. The choice of whether a window with a high or low SHGC value is better depends on the location of the investment.