Tax Credit Amount: 10% of the cost, up to $500, but windows are capped at $200.

Must be ENERGY STAR qualified.
You do not have to replace all the windows/doors/skylights in your home to qualify.
And it doesn't need to be a replacement either - installing a new window where
there wasn't one previously (like in an addition) qualifies.
Tax Credit does NOT include installation costs.

Get your Manufacturer's Certificate here.

Learn how to file here.