This paper presents the personal experience of one of the co-authors through three stages of their research career: predoctoral, post-doctoral, and as a professor co-directing a Doctoral Thesis. The common thread throughout these stages was participation in two international research projects related to improving the energy efficiency of buildings at different scales: IEA EBC Annex 75 and INHAVIT. Collaborations were established with researchers from the University of Burgos, the University of Minho, and the University of the Basque Country.

During the predoctoral stage, a research stay was conducted at the University of Minho, participating in the IEA EBC Annex 75 project. Energy simulations and cost-effectiveness studies have been performed for a residential complex in Braga, Portugal. Weaknesses include a lack of prior knowledge of Portuguese regulations and limited integration with other researchers. The strengths were familiarity with energy simulation programs and previous knowledge of the country and local customs.

In the post-doctoral stage, a research stay was conducted at the Laboratory for Quality Control in Building of the Basque Government, collaborating with the University of the Basque Country in the IEA EBC Annex 75 project. Energy simulations were conducted for a neighbourhood in Vitoria/Gasteiz, Spain. Challenges include the use of different simulation software and the need for daily commuting. Strengths include pre-planning of the stay, prior experience in energy simulation, and strong integration with the host research group.

As a professor and co-director of a Doctoral Thesis, this work is being developed within the INHAVIT project, studying vernacular dwellings in Montesinho Natural Park, Portugal. Difficulties include access to dwellings and communication during remote meetings. However, previous research experience and participation in international projects facilitate collaboration and work planning, allowing for the detection and resolution of students’ training deficiencies.

Participation in international research projects is essential for learning about a research career, building relationships, and strengthening research to address global issues. The weak and strong points found at each stage serve as learning elements, leading to continuous improvement and the acquisition of useful tools for research and teaching in the future.

Keywords: Buildings, Doctoral Thesis, Energy efficiency, Energy simulations, International research projects, Research career.