This paper aims to study the required solar panel tilt angle, area, and investment payback period for achieving zero-energy heating in historically significant courtyard-style residential buildings. The retrofitting approach involves positioning solar panels on the main building of the structure using four supports, each located at the corners, elevated from the ground and not in direct contact with the building. This approach does not alter the external envelope structure of the building, thereby preserving the authenticity of the cultural heritage. Using BESI software, we simulated the heating energy demand of the sample building. We integrated a solar heating system within the building and analyzed the optimal solar panel layout area, installation angle, and payback period for achieving zero-energy heating. This allowed the building to meet the zero-energy heating requirements. Taking the Hu Family Courtyard heritage conservation building as an example, we proposed the optimal layout plan for solar energy retrofitting.