Dual temperature buildings utilize a hydronic loop for both heating and cooling and typically rely on steam boilers or utility steam and steam-fed chillers. These buildings typically use at least 20% higher energy use indexes (EUIs) with 15% higher carbon emissions than similar buildings that lack central cooling. Dual temperature buildings will need a capital plan for complying with LL97, which requires 88% reduction of carbon emissions through 2050. We will present case studies that showcase best practices and HVAC design considerations, carbon, energy, and cost savings data, and construction hurdles and outcomes. Our presentation provides a framework to make sustainable and cost-effective decisions when investing in carbon-reduction upgrades to dual-temperature buildings under the lens of LL97 and its carbon-reduction goals.