Amount qualifying for credit which was 10% of film
cost up to maximum total credit of $500 is increased
retroactively for qualifying window film installations
to January 1, 2009, to 30% of film cost (does not
include any labor cost for installation) up to
maximum total credit of $1,500.  This credit is in
addition to any credit used in previous years.

The tax credits for qualifying window film
installations have been extended through the end of
2010. However, the new standard for compliance for
films will be the 2009 International Energy
Conservation Code (IECC) have changed and are
more stringent. In order to take advantage of this tax
credit you must obtain certification from the window
film manufacturer in order to qualify for the Federal
Tax Credit for Energy Efficiency.  The window film
installed must be certified by the manufacturer to be
an Eligible Building Component Envelope in your
geographic area.  Houston and surrounding area are
in zone 2.

The tax credit is dollar for dollar in the amount of
taxes you pay, not just a tax reduction from income.  
However, it is only the 30% cost of the film itself up
to $1500 and does not include any labor cost for
installation.  
The truth about the Federal Tax Credit For
Energy Efficiency