Illinois street multifamily project is a new 3 story, 12 unit apartment building with 1 additional ADU located in San Diego, CA. Each apartment unit is a 1 bedroom, 1 bathroom and approximately 500 sqft. The mechanical system consisted of ductless split system heat pumps for each unit along with exhaust fans and supply fans for ventilation air. The plumbing system consisted of a central heat pump water heater located on the roof, complete with a hot water return piping scheme for on demand hot water.