Generally speaking, the entry for Energy Efficient Home Improvements should be on the Deductions and Credits page under "Your Home." You may have to click something like "show me all options" or "show me more" if you don't see it.
For windows, they must meet Energy Star version 6.0 or higher, per the instructions for form 5695 line 19d. Also, there is a maximum lifetime credit for energy efficient building improvements of $500 and a maximum lifetime credit for windows of $200, so if you have used the credit before, it may not be allowed now. Also, the credit is 10% of the product cost not counting installation, so if you are audited, you will be at risk of losing the deduction unless the cost is listed separately on your invoice.
