Installation of solar PV is a measure that can contribute to great climate benefits when renovating buildings. This report, which is the final report of the project "Optimized renovation for efficient PV roofs" (short called EST), describes how property owners can contribute to increased climate benefits by considering the possibilities with PV installations when planning to renovate a building. The focus of the work has been PV installation in connection with roof renovation, but facades, which are increasingly mentioned in PV discussions, are also treated and we also touch on solar shading and balcony fronts that are potentially interesting for solar PV integration. Climate benefit means a minimization of the greenhouse gas emissions that occur through the energy use in the building and in the production of the building's constituent building materials, and that the excess solar exported from the plant can replace fossil-based power production, see sections 2.1 and 2.2. Section 2.3 “Well-planned solar PV renovation” gives an overall picture of the challenges facing those who want to achieve the greatest possible climate benefit, challenges that are discussed in the following sections. In the project, we have investigated different ways of maximizing the size of a photovoltaic system based on what the roof of a building can accommodate, which means that the size is optimized with regard to the climate benefits. In general, this gives a different result than an economic optimization where the latter results in significantly smaller systems. The reason is that the sale of larger electricity production surpluses in this segment is currently not as profitable as replacing the electricity you buy, with self-produced electricity. Most research reports and guidelines on the topic of optimal plant size also stop at economic optimization, often without even mentioning the possibility of going further to increase climate benefits. In this project, we have basically done the opposite, without turning a blind eye to economic realities. In section 3, we deal with architecture, planning and permit issues and argue that the strategy we advocate also leads to better architectural solutions than state of the art. The focus has been on presenting several concept solutions that aim to maximize the utilization of the available roof space, see sections 4 and 5 and Appendix 2. Our motives for this are partly a feeling of high importance when it comes to accelerating the introduction of renewable energy production in the built environment. Another is a hope and a belief that politics and the market both contribute and will continue to contribute to a development that makes maximized climate benefit a much better deal for the plant owner than it is today. Section 6 briefly discusses a few different measures to increase the own use of the solar electricity one can produce, which enables building a larger facility while maintaining good finances. One of these measures — collective measurement of the apartments' household electricity - is dealt with in more detail in Appendix 3, which is a guide aimed at property owners. The project's initial hypothesis was that simultaneous renovation of roofs and installation of solar PV was an optimal approach. The results from more in-depth investigations of, for example, contract forms and tender documents in section 8 and from the seven case studies presented in section 9, have led to a more nuanced picture: • It may sometimes be better to install solar cells after the roof or facade renovation has been completed, but even if it is expected to take place later, there is every reason to take this future work into account when planning a renovation. Conversely, there are good reasons to think through your renovation needs if you are considering investing in a solar PV system. • In addition to renovating the climate shell of a building, renovation of the ventilation and electrical systems can also have a major impact on the technical and economic potential of a future PV system. • City planning and the building permit requirements for building-integrated solar cell solutions can sometimes be a major challenge when you want to maximize the solar PV surface on a roof in connection with renovation or extension, which is dealt with in section 3. In section 10, we finally discuss the experiences and results that the project has led to. We also describe four projects that in different ways pave the way for the continued introduction of solar PV in buildings and describe how the work in the EST project can be taken further in future projects.