The notice intentionally does not identify HUD-approved tools as the field is changing regularly. This is the pertinent language in the notice:
“The energy consumption model must, at a minimum, take into account specific factors including, but not limited to, unit size, building orientation, design and materials, mechanical systems, appliances, and characteristics of the building location. Second, the
utility estimates must be calculated by either (1) a properly licensed engineer or (2) a qualified professional approved by HUD.”
One example, however, is the CUAC tool, which is available for use in California, from the website of the Tax Credit Allocation committee. For the specific question regarding approval by HFAs, O/As would need to contact the relevant HFA directly.