Our free calculator uses recent, trusted data to estimate costs for your Window Casing Installation project. For a basic 125 linear feet project in zip code 47474, the benchmark cost to Install Window Casing ranges between $2.98 - $5.71 per linear foot.To estimate costs for your project: 1.Set Project Zip Code Enter the Zip Code for the location where labor is hired and materials purchased.or a basic 125 linear feet project in zip code 47474, the benchmark cost to Install Window Casing ranges between $2.98 - $5.71 per linear foot.