USai 3.0

A complement for Lesosai

USai 3.0 is a software developed by E4tech Software SA since 2008. USai 3.x is, as its name suggests, the third version.

USai was born from the software Lesosai (, with the objective of giving customers a simple tool to calculate the U-value of the constructions. As the months and the requests from clients, USai was developed to get to version 3.x that allows, among other (free version):

  • Manage projects of buildings (facades, ceilings, floors, doors)
  • Calculate the coefficient of transmission of heat (SIA180, EN ISO 6946)

And in the paid version:

  • Take into account the dynamic characteristics according to the standard EN ISO 13786 (factor of depreciation, dynamic heat transfer coefficient, thermal admittances)
  • The calculation of the risk of internal condensation and water condensed according to EN ISO 13788, EN ISO 6946 and SIA180
  • Calculate grey energy CO2 equivalent UBP (ecopoints) from the list KBOB (an extract of the Ecoinvent database), and data from manufacturers, according to the technical specification SIA2032. The same method is used for Minergie - ECO® 2011.
  • Integrate Meteonorm® monthly to obtain weather data from around the world for the calculation of condensation
  • Use the official climate stations Swiss according to SIA2028
  • Allow to calculate the annexes of the standard EN ISO 6946, fixing mechanical, empty of air
  • Results can be used in the " " Program buildings climate cent "or fill in the form-2A "


Assistance in decision of investment

Thanks to its features, USai 3.0 helps greatly in the decision on the appropriateness of a investment in the restoration of a building. Taking quick and our efficient after-sales service guarantee you a fast and reliable result and a real saving of time and money.

In addition, USai is connected to the database of several large producers of materials thanks to the platform .


Information and order on the site of the software USai :