Could I claim a new A/C unit that I need to put on my house which was over $4000
Yes, if the unit meets the requirements. Check the Energy Star Website linked below.
This is entered in the Deductions & Credits section:
With your return open, search for energy improvements in
the program search box. (Don't search for "energy credit," as
this will take you to the wrong place in the program.)
to energy improvements in the search results.
At the bottom of the Energy-Saving Home Improvements screen,
answer Yes and
Follow the on-screen instructions.
If that doesn't work:
Go directly to the Federal Taxes tab, then Deductions & Credits,
then Your Home, then scroll to Home Energy Credits.
Tip: You can see which energy-saving home improvements qualify
for a federal tax credit at the Energy Star website.
The Residential Energy Efficient Property Credit is
what is called a "non-refundable" credit which means it
will only reduce your tax liability to zero. Any remainder can be
carried forward to the next year.