Software for the heat flow evaluation of the nearly-zero houses

The windows in a building are the weakest part for energy saving and reduced consumption. In particular, the choice of window frames and glazing systems directly influences the amount of heat loss through a houses envelope. The paper will show the results of a work developed by PADesign srl company (Accademic Spin off of the Università degli Studi di Palermo). This is a software tool that allows a rapid comparison about the windows thermal performances, by calculating the global thermal transmittance and by showing the trend of the heat flow. The tool has a simple graphical interface that allows the users to select the climate data, the window typologies, the geometric features and the materials of window frames and glazing system. The tool calculates the global thermal transmittance and checks the compatibility with the limits set by Italian law. The possibility of immediately view the heat flow through an envelope of the selected combination allows you to identify the possible thermal bridges. It also allows to try out other combinations of the envelope stratigraphy, in order to optimize the choice of components providing the most suitable thermal performance. The tool can be implemented for all typologies of frames and glazing systems. Moreover, the software tools for evaluating energy efficiency and sustainability in buildings are very important to meet the restrictive requirements of thermal transmittance, provided by national and international regulations, and according to the Europa 2020 goals. It was developed in Java language to ensure portability across platforms. It uses a software library split that implements a self-contained, server less transactional SQL database engine. To generate outputs, the tool uses data and results provided by “LBNL WINDOW” and “LBNL THERM” software, for which we hold the commercial license. The software is aimed at a wide audience cause it does not require specific technical skills.