A hydraulic elevator uses a hydraulic cylinder (jack) driven by a hydraulic power unit to raise and lower the elevator car. The pump pressurises hydraulic fluid into the cylinder to lift the car, and a controlled valve release lowers it under gravity. Hydraulic elevators are ideal for low-rise buildings (up to 6–8 floors), offer smooth operation, and do not require a structural overhead machine room. They have lower installation cost but higher energy consumption compared to gearless traction elevators, and require regular hydraulic fluid maintenance.