Can we claim the cost of energy efficient windows and glass sliding doors, as well as low flow toilets, that were professionally installed in our home in 2019?

Windows and doors that meet the energy standards set forth in the tax code or eligible for a 10% credit, of the cost of materials only not including installation, up to a lifetime maximum of $200 per taxpayer. I can’t tell you what the standards are, you will have to check with the door and window manufacturer.  And, if your bill does not break out the cost of materials and labor from your contractor, then you may have a hard time substantiating your claim for a credit if you are audited. (The IRS does not have to award any deduction that you can’t prove to their satisfaction.)  

Discredit his claimed on the energy efficient property credit on form 5695, and you can access the interview on the deductions and credits page. The lifetime maximum for this credit is $500 for all types of improvements and a lifetime credit maximum four doors and windows is $200, so you will have to be aware if you claim does credit at any time in the past, going back to 2006 when it was first added to the tax code.

Low flow toilets are not eligible for any tax credits.