This study introduces a streamlined framework designed to enhance the characterization and dimensioning of heat pumps in renovation scenarios, where data is often incomplete and conditions vary significantly from new constructions. De-tailed dimensioning methods are data-intensive and time-intensive, limiting the implementation rate of heat pumps in renovations. To address this, the research develops a framework that employs simplified dimensioning methods to assist the designer in integrating heat pumps into renovation projects. This method characterizes the current state of buildings and HVAC systems, utilizing existing tools alongside advanced research methodologies. By assessing the usability and accuracy of these simplified dimensioning methods the developed approach ensures the effective incorporation of heat pump systems, optimizing the thermal performance and energy efficiency of renovated buildings. A robustness analysis was conducted on four case study buildings to compare the simplified method with the detailed dimensioning methods. This analysis further examines the sensitivity and limitations of the proposed methods, focusing on how varying input levels of detail affect the accuracy in predicting system requirements. This research delivers a comprehensive approach to optimizing heat pump integration in renovation projects, offering practical solutions for reducing the carbon impact of HVAC systems and improving retrofit efficiency.