I'm not aware of a $1500 home improvement credit. Please explain more of what you are referring to.
There is the First Time Home buyer credit of $8,000, there is energy efficiency credits, there is new home credits of $10,000. All have stipulations and conditions for qualifying for these. And all of these are independent credits that can be used at the same time, provided you qualify for each of the unique conditions.
What is the $1500 home improvement credit, who is offering it, and under what conditions is it offered?