If complete black out is needed, we recommend ordering outside mount. An inside mount shade will have small gaps between the shade or blackout blinds and the window sill where light will filter through. If inside mount is needed, we have our EcoTrack products that are built with inside side tracks that will close that gap between the shade fabric and the window sill.
*Shades must be ordered with blackout liner option to be made as blackout shades. Blackout liner is an option that can be selected while placing the order.