Roof box vs rear mounted box – Which saves more fuel?

Adding extra storage to your car often raises one big question: how will it affect fuel efficiency? The answer comes down to one key factor – aerodynamics.

The problem with roof boxes

Roof boxes sit on top of your car, breaking up its natural airflow. This creates drag – the resistance your car has to push through as you drive.

Up to 40% more drag: A roof box can increase aerodynamic drag dramatically, which means your engine (or electric motor) has to work harder.
Higher fuel consumption: More drag = more fuel burned.
Range reduction for EVs: For electric cars, that extra resistance can mean noticeably fewer kilometers per charge.
Noisy rides: Roof boxes often create turbulence, leading to constant wind noise at higher speeds.

Why rear mounted boxes are more efficient

A rear mounted cargo box like IXTAbox is placed at the back of the car, following its natural shape and allowing air to flow more smoothly.

Up to 5% drag reduction: Properly mounted, IXTAbox actually improves aerodynamics compared to driving without a roof box.
Fuel savings: Less drag means lower fuel consumption on long journeys.
Longer EV range: EV drivers especially benefit from keeping every extra kilometer of battery life.
Quieter driving: With less turbulence, the cabin remains calm and comfortable, even at highway speeds.

More space, less cost

With up to 390 liters of storage capacity, IXTAbox lets you carry skis, snowboards, camping gear, or everyday luggage – all without sacrificing efficiency. Instead of paying more at the pump or stopping to recharge more often, you can enjoy the trip with peace of mind.