kinda vague there, 5.25 or not, window or not etc etc... dust filters kill airflow. just clean it more often. built in one of these, it was good: https://www.newegg.com/Product/Product.aspx?Item=N82E16811139089 these are decent: https://www.newegg.com/Product/Product.aspx?item=N82E16811119314 you have LOTS to choose from https://www.newegg.com/Product/Product.aspx?Item=N82E16811139089
While unlikely to have the airflow of a complete mesh fronted case, this is the one that caught my eye when looking for a budget case... and gets high praise in reviews: Phanteks Eclipse P300 I didn't have a lot of luck finding in depth reviews of this one (at least not the X variant) but the side intake and the optical drive bay interested me: Cougar MX330-X
Check out these prices https://slickdeals.net/newsearch.ph...earcharea=deals&searchin=first&sort=relevance