These days systems for housework automation become more and more popular, as well as a trend of intelligent households develops. This paper deals with description of problems while creating a mobile application intended to facilitate the household care in area of drying clothes. The application uses technology of acquiring user’s location by GPS or Wi-Fi module and communication with a web service. This paper focuses particularly on fundamental application functionality, which is a recommendation, whether it is advisable to hang outside clothes that just have been washed and for how long. The calculation of the time when the laundry will be dry depends on many variables, including detected weather in the given area. The problem was solved using a calculation of absorbing water into air, which unwinds of formulas for calculation of water vapour pressure. Therefore the result of the project is an application using the abovementioned calculations for practical simplification of household care.