Heating buildings is a pressing issue in the UK given the UK's commitment to achieving net zero emissions targets. To solve this problem, a building strategy to effectively reduce energy consumption by simulating and modifying window size parameters is developed. This study mainly uses computer simulation experiments to evaluate the impact of optimizing window size on energy consumption during building renovation. For this purpose, a detached building located in Nottingham, UK was chosen as a model. The results of the study show that the south side of the building has the most significant impact on energy consumption. Therefore, by increasing the size of the south-facing windows, the overall energy consumption of the building can be significantly reduced. The study showed that the ideal window size increase was 1.6 times the original size, resulting in a window-to-wall ratio of 7.86% compared to 4.91% of the original size. When the technology of changing the window size is combined with multi-layer glass windows filled with xenon and Low-E vacuum windows, the building energy consumption can be better reduced, which can reduce the total energy consumption by 2.65% and 4.14% respectively. On the contrary, the study highlights that the presence of north-facing windows has a negative impact on the building's energy consumption. The findings have important implications for window reconstruction in British buildings. The research methodology and results can provide a valuable reference for architects and engineers seeking to optimize window design to minimize energy consumption in various types of residential buildings. By applying a similar window optimization approach, it is possible to determine optimal values for reducing energy consumption in different types of residential structures. The research demonstrates the potential to improve the energy efficiency of buildings and contribute to the UK's wider efforts to achieve net zero targets. Implementing these findings in building renovations could pave the way for a more sustainable future and promote energy awareness in the building industry.