residential clean energy credit - how do I enter 2 air condensers

The Energy Efficient Home Improvement Credit is only available for a home in the United States and used by the taxpayer as the taxpayer's principal residence. Therefore, only one air conditioning unit installation would be allowed for the credit. If more than one was installed in the same property, you can combine the total of the two, but the credit is limited to $600.

What type of residence is required for the credit?

Air conditioners do not qualify for the Residential Clean Energy Credit. Qualified expenses include the costs of new clean energy property including:

• Solar electric panels
• Solar water heaters
• Wind turbines
• Geothermal heat pumps
• Fuel cells
• Battery storage technology (beginning in 2023)

Used (previously owned) clean energy property is not eligible.

Residential Clean Energy Credit

However, they may qualify for the Energy Efficient Home Improvement Credit, which is limited to $600 for air conditioners. They are reported on line 22a of Form 5695. Per the IRS:

Residential energy property that meets or exceeds the Consortium for Energy Efficiency (CEE) highest efficiency tier, not including any advanced tier, in effect at the beginning of the year when the property is installed qualifies for a credit up to $600 per item. Costs may include labor for installation.

Qualified property includes new:

• Central air conditioners
• Natural gas, propane, or oil water heaters
• Natural gas, propane, or oil furnaces and hot water boilers

Oil furnaces or hot water boilers can also qualify through other efficiency criteria.

Costs of electrical components needed to support residential energy property, including panelboards, sub-panelboards, branch circuits, and feeders, also qualify for the credit if they meet the National Electric Code and have a capacity of 200 amps or more. There is a limit of $600 per item.

@agnesjane1 

The maximum credit is $600 per year, not $600 per unit.  If they were both installed on your main residence, combine the prices.