The Gebäude-Energie-Spar-Check app by Viessmann is a free Android app that aims to help users determine the efficiency of their heating systems. The app offers a simple and quick way to analyze the performance of the heating system without much effort. Additionally, the app provides a proposal for the modernization of heating systems up to 60 kilowatts. By entering some parameters of the old heating system, the app generates a modernization proposal.

The app provides users with information about how much energy, money, and CO2 they can save after modernizing their heating systems. Users can also request additional information or professional advice from the developer. The app is a useful tool for anyone who wants to save money and reduce energy consumption by improving the efficiency of their heating systems.