This dataset shows values of air temperature and relative humidity in two houses that were monitored for 3 years. The houses are side by side in a village in the Litoral Mountain range of Tarragona (Spain). The houses have the same orientation (east-west), an equivalent position in the village and an equivalent configuration, but different architectural construction systems. Five TESTO 175 H1 data logger were used to take measurements of air temperature and relative humidity each 20 minutes in different spaces, starting at the o’clock. The dataset also includes the values of outdoor temperature, relative humidity, and irradiation in the same village. The data was obtained from a weather station located close to the houses. The collection of data started in September 2019 and finished in September 2022. The format is a set of 6 calculation sheets including all measurements in house1, house2 and outside. It is valuable for those who want to compare the thermal performance of two types of building construction during a long period of time, in use and under similar operation conditions.