If you perform energy models, you may learn that some firms focus entirely on 179D sometimes called EPACT.  A full energy model isrequired to claim the greatest tax incentive. However, an energy model is not required, as you can take a partial rebate by evaluating any single item or combination of the envelope, the lighting, or just the HVAC equipment.

Section 179D of the Internal Revenue Code is a tax incentive for commercial building owners and tenants to improve the energy efficiency of their buildings. Depending on the current law, it allows for a tax CREDIT of up to $1.80 per square foot (it may change each year depending on Congress and you will need to check with a qualifed tax professional). This money helps cover the cost of installing energy-efficient systems and equipment in a commercial building.

It is worth noting that many 90.1 or LEED certified buildings qualify for this tax incentive and sometimes the LEED model is used to obtain the 179D credit.

To qualify for the 179D tax deduction, a building must meet certain energy efficiency standards set by the Department of Energy (DOE). These standards vary depending on the type of building and the systems and equipment being installed. The DOE also provides guidance on how to calculate the deduction, which is based on the cost of the energy-efficient improvements and the amount of energy they are expected to save.

The 179D tax deduction can be a valuable tool for building owners and tenants who are looking to reduce their energy costs and improve the sustainability of their buildings. It can also be an incentive for building designers and contractors to incorporate energy-efficient features into their designs and construction projects (because designers or contractors can claim the tax credit or part of it)