Many cities have prohibited natural gas for space and water heating in new commercial buildings to reduce greenhouse gas emissions. Electrification and decarbonization polices will dictate electric heating. Electric boilers and resistance heat are inefficient and expensive to operate. Air-source heat pumps will provide much of the heat in milder climates, but they are not suited for colder climates (<0F). Capacity declines at low temperatures will require multiple units, increasing costs, and there may not be sufficient roofspace in dense urban areas. A new system that combines air-source heat pumps, water-source heat pumps, and ice storage tanks will provide an efficient solution. Water in the ice tank is 32F. Freezing that water removes 144 Btu/lb. That energy is transferred to the condenser, and it can provide 100F-120F HW for space heating. This will be used for morning warm up when it is coldest outside. The ice will be melted later in the day using internal loads and ready the tanks for heating the following day. Using the 32F water as an energy source is much more efficient than using air at 0F.