The credit expired at the end of 2016 so it's not on the tax form. The credit was extended to the end of 2017, retroactively, in the Feb 8, 2018 budget bill, but the IRS has not yet announced how they will be handling it. (I would expect they will put it back on the form, but since so many people file early, there's a chance they will allow the 2017 credit to be claimed on next year's return.) After the IRS announces how they will handle the changes, it will likely be a month or more for them to update their computers and then authorize tax software companies to make the changes as well.
At this point you can either file without the credit and maybe have to amend later, or wait and see what happens.
Also, "Energy star" does not necessarily indicate the unit is qualified for the tax credit. An air conditioner must be in the highest efficiency tier as established by the 2009 International Energy Conservation Code as in effect (with supplements) on February 17, 2009. This might or might not coincide with Energy Star certification, but you would have to ask the manufacturer to be sure.