Yes! OptiMiser has passed Bestest, the industry standard test for accuracy in residential building energy modeling.
OptiMiser is also RESNET HERS accredited. The full HERS accreditation requires passing accuracy test for HVAC and DHW systems in addition to the BESTEST suite, which only tests heating and cooling loads.
The modeling engine is constantly evolving, but we routinely run it against the BESTEST suite of tests as well as the various systems tests in the full HERS accreditation series. We have not submitted our current version for accreditation because we are waiting on RESNET to resolve of an inconsistency in the latest revision of the HERS Standard. We also are not currently marketing OptiMiser for HERS ratings, though we may in the future.