Heat2O® is a cold-climate heat pump water heater designed to provide Domestic Hot Water (DHW) in high-demand commercial applications while reducing environmental impacts. DHW accounts for roughly 25% of annual energy use in multifamily buildings. Boasting a coefficient of performance up to 4.52, Heat2O® cuts on-site carbon emissions and offers energy savings of up to 70% compared to electric-resistance water heaters. We design energy-efficient heat pumps like Heat2O® with consideration for existing codes and standards and future requirements, further contributing to sustainability.