We purchased a new A/C unit for the house. I have a home office can I deduct the new ac there or is there another place where I will get a bigger deduction?

If you mean Central Air, first determine if it qualifies for an energy-efficient tax credit. An energy credit may be available:

https://www.energystar.gov/about/2016_federal_tax_credits

If so, enter under Federal Taxes (or Personal in some versions of Self Employed)- Deductions and Credits- Your Home- Home Energy Credits.

If you qualify for this, you may literally receive (up to) a $300 tax credit. If you do, reduce your cost by the amount of the tax credit when entering under the Home Office section.