Where do I enter the tax credit for having a qualified air conditioning system installed in our home in 2016?

Your energy-efficient central air-conditioning system may qualify for an energy credit. You'll enter the cost of the AC system under Tell Us How Much You Paid for Energy-Saving Improvements as an Energy-Efficient Building Property. (Click the screenshot below for reference.)

To enter your energy-efficient property in TurboTax:

• Open (continue) your return in TurboTax Online. (If your return isn't open, you'll need to sign in, click Take me to my return, then click Pick up where I left off.)
• Click My Account (top right of your screen).
• Select Tools.
• In the pop-up window, select Topic Search.
• In the search bar, type 5695.
• In the results box, highlight 5695, residential energy credit, then click GO.
• Follow the onscreen instructions to complete this section. Enter your AC system as an Energy-Efficient Building Property. (Be sure to click the Learn more links if you have any questions.) 
• After you enter the cost of your air-conditioning system and answer the corresponding questions, TurboTax will determine if you qualify for an energy credit.  

Note: If using the TurboTax CD/Download software, you'll use the Find function (instead of "My Account") to search for the topic.

The Nonbusiness Energy Property Credit has a lifetime total combined limit of $500 ($200 of which may be for windows), so if you have claimed the credit in a prior year your 2016 deduction may be reduced. See IRS Instructions for Form 5695, Residential Energy Credits for more information.

The FAQ below has links to websites where you can see if your energy-efficient property qualifies for a tax credit.  https://ttlc.intuit.com/replies/3300639