I purchased the new air conditioner. Can I claim tax credit ?

Was it a central air unit?  Or a window unit?  If it was a window unit no, if it was a central air unit, then possibly. 

The Home Improvement Energy Efficient Credit is a non-refundable credit

• Worth up to 30% of qualifying costs for a maximum combined total of $1,200 for the following:
  • Doors, Windows and Skylights
  • Insulation
  • Natural Gas, Oil Propane Water Heaters
  • Furnaces
  • Boilers
  • Central Air Conditioners ($600 maximum Credit)
  • Electrical Panel Upgrades
  • Home Energy Audit (up to $150)
• You can combine the $2,000 credit with the $1,200 credit for a total of $3,200
• This credit is a use it or lose it credit.  If you do have enough tax liability in the year you buy and install the item, you will not be able to carry the credit forward.
• NOT available for new construction.