Cost to Screen In Porch. The cost to Screen In Porch averages $4.74 - $6.83 per square foot in 2014. This Screened In Porch Installation cost estimate is calculated from average material costs, unit labor producitivity rates and national average hourly labor wages.To refine the estimate for your Screened In Porch Installation project: 1.he cost to Screen In Porch averages $4.74 - $6.83 per square foot in 2014. This Screened In Porch Installation cost estimate is calculated from average material costs, unit labor producitivity rates and national average hourly labor wages. To refine the estimate for your Screened In Porch Installation project: