Kia's 'EcoDynamics+' mild hybrid system which features in the MHEV 1.0 T-GDI 118bhp model works as these kinds of set-ups usually do. It supplements the engine's torque output with power from a compact 48-volt lithium-ion polymer battery and extends engine 'off time' with a Mild-Hybrid Starter-Generator (MHSG) unit. The MHSG is connected by a belt to the engine's crankshaft and switches seamlessly between 'motor' and 'generator' modes. In 'motor' mode, under acceleration, the MHSG provides electric power assistance to reduce engine load and emissions. As the car decelerates, the MHSG has the ability under certain conditions to switch to 'generator' mode, recuperating energy from the crankshaft to recharge the battery. As a result, impressive WLTP-rated returns are possible - up to 52.3mpg on the combined cycle and up to 122g/km of CO2. Even the conventional 1.0 T-GDI 99bhp petrol engine should certainly prove to be very frugal. This base T-GDi unit manages virtually the same figures are the MHEV version - 52.3mpg on the WLTP combined cycle and 123g/km of WLTP-rated CO2. The base 1.25-litre model manages 49.6mpg and 128g/km. All variants get an Idle Stop & Go (ISG) system that cuts the engine when you don't need it, stuck at the lights or waiting in traffic. As with all Kias, the Rio is covered by a seven-year, 100,000-mile warranty that's longer than any other car in the same class. Servicing should be affordable and the various pre-paid servicing packages you can buy will further help manage costs in this regard, with 'Care-3' or 'Care-3 Plus' packages offering retail customers fixed-cost, inflation-proof servicing for either three or five years. Should you sell the car in this period, the remaining scheduled maintenance allocation can be passed on to the next owner.