Background: Buildings account for a high share of U.S. energy use; therefore, the construction industry is a key player in enabling U.S. national decarbonization and grid demand reduction. Objective: This review makes a systematic and thematic synthesis of quantitative evidence regarding the implementation of green building technologies in buildings deployed in the U.S. from 2011-2025, with an emphasis on metered or validated (through simulation) energy performance metrics. Methods: Using a structured process for screening studies, selecting eligible studies, and evaluating design, 22 eligible studies were identified covering U.S. single-family homes, commercial offices, K-12 (including school campus) learning facilities, federal facilities, military bases, and campus case studies. Interventions were grouped either under HVAC/mechanical systems, building envelope retrofits, certification systems impact, renewable integration, and validated energy modelling. Results: HVAC and control system upgrades, including packages validated by Lawrence Berkeley National Laboratory, were proven to have the highest and most consistent HVAC energy reductions (unit level at 57 - 61%). Residential Deep Energy Retrofits, evaluated by Less and Walker (2024), achieved an average net-site energy savings of 47% by making large airtightness improvements. Targeted envelope upgrades (storm windows, interior glazing, internal test surfaces, installation, etc.) were tested in Seattle historical homes and offset 22% of the HVAC load. In contrast, studies that measured LEED certification indicated high levels of predicted vs. actual performance variability, negligible average source-energy savings in federal and Chicago benchmarking cohorts, and, in some instances, 17% higher consumption in LEED-certified schools. Modelling studies by the National Institute of Standards and Technology Net Zero Energy Residential Test Facility confirmed that over-prediction errors as large as 25% were due to occupancy assumptions. Conclusion: Targeted, metered, and commissioned technologies provide the most reliable energy-efficiency payback in high-performance construction in the United States. Certification, in the absence of sub-metering and commissioning, and ongoing validation, merely assures expectations but does not assure results.