Effects of climate change on a cold attic performance are considered. The hygro-thermal responses of the attic to different climate data sets are simulated numerically using different weather data sets for the period of 1961-2100 in four cities of Sweden. The weather data sets, which are the results of climate simulations, enclose different uncertainties. The uncertainties related to differences in spatial resolutions, global climate models (GCMs), CO2 emission scenarios and initial conditions are considered here. Analysis of the long term climate data demands suitable statistical methods. Nonparametric and parametric methods have been applied for analyzing the data. Using suitable statistical methods helps in understanding the importance of different uncertainties in the weather data and their effects on the attic simulation.