Including Custom Post Types in search results generally has a minimal impact on your site’s performance, especially if you are using a well-optimized theme and have a good hosting environment. However, the performance impact can vary depending on how many CPTs and posts you have, as well as how complex your search queries are. To minimize performance issues, make sure to optimize your database and use caching plugins where appropriate. If you’re using plugins for search functionality, choose ones known for their performance and efficiency.