Perceived Value = Actual cost x 3
In renovation, perceived value means the value worth that a physical change has in the mind of owners or buyers.
Actual cost is the cost spent making the change.
The perceived value added to a property will also depend on a number of other factors including the actual value of the property to begin with (low, medium or premium value property), the location, the environment, the changes made and the quality of the changes.
A cosmetic or structural renovation is a realistic way to increase property value. Any intended changes should have some strategic thought and careful planning. No matter how much or how little the change of property, changes must be highly visible in order for someone to see a real difference in the before and after status of the property. From my experience, in the most optimised situation, the perceived value will be the 3 times of the actual cost. Always remember, the aim when renovating is to get the biggest bang for your buck at the least cost possible.
Example of Apartment having good renovation:
http://www.morris-property.com/post/136720466642/
When comparing to:
http://www.morris-property.com/post/136184394692/
(The above samples are taken on the same floor of a building in centre part of Kowloon, Hong Kong to reflect the rental value difference based on the renovation and decorations)