Window grids can increase property value if they are aesthetically pleasing and complement the architecture of the property. If you have a colonial style property or if your façade has Tudor influences, putting window grids can enhance the appearance and thereby increase the value of the property. Victorian homes also look stately with window grids. However, if you have a modern styled house or a split-level or ranch styled home, its best to steer away from window grids as they create a boxed-up appearance and can considerably reduce the value of the property. Grids also do not add any visual enhancement to Mediterranean and Spanish or stucco themed properties.