We begin this exercise with the blazing summer heat blanketing the Renault Duster and Tata Sierra. The ambient temperature at our test site on the outskirts of Mumbai peaked at 42.2deg C. It wasn’t just the high temperature that would put these climate control systems through their paces but the high humidity as well. Having said that, here’s how these two midsize SUVs fared in our AC performance test.
Explore full specs, features and a price breakdown in our Duster vs Sierra comparison.
Autocar India’s testing methodology
In preparation for the test, each car is parked under direct sunlight for two hours with its engine switched off and windows rolled up. Sunroof shades are kept closed, but rear window shades are rolled away. Once a car is ‘soaked’, a two-member team enters the vehicle quickly to minimise heat loss – our job is to simulate a worst-case scenario. Each car is equipped with sophisticated test gear provided by Zen Microsystems. Five thermocouple sensors read ambient temperature, cabin temperature, vent temperature (capturing how cold the air is), front-seat temperature (measured near the driver’s ear) and rear-seat temperature (measured at the rear centre armrest).
Front vents are directed at the driver’s face, while rear vents are aimed at the occupant seated in the centre. As the car is switched on, climate control is set to recirculation mode, maximum blower speed and the lowest possible temperature. Temperature readings are recorded after a minute of idling and then at five-minute intervals (up to 15 minutes) while driving on a fixed route at 50-60kph. A final reading is taken after another minute of idling.
A key disclaimer: Ambient temperatures and humidity have a big bearing on cooling performance. Hence, our results are from vehicles tested on the same day, and these may vary for you based on your location and ambient conditions.
Renault Duster vs Tata Sierra AC test
1. Renault Duster front and rear AC performance
The thermocouple sensors installed in the Renault Duster’s cabin recorded a peak temperature of 51.2deg C at the start of our AC performance test. A minute after turning on the Renault SUV’s two-zone automatic climate control system, its front cabin temperature fell by 5.7deg C. The drop in temperature accelerated as we began driving the Duster, with the mercury falling by 12.3deg C in just 5 minutes. The lowest temperature recorded at the front of the Duster’s cabin was 30.5deg C, marking a drop of 20.7deg C since the beginning of this test. However, during the last minute of idling, the temperature up front rose by 4deg C.
The highest temperature recorded at the rear of the Duster’s cabin was 50deg C. The rear cabin temperature fell 5.5deg C after one minute of idling, and it dropped to 31deg C 16 minutes into our test. Accounting for a 2.5deg C increase in temperature towards the end of 17 minutes, the overall drop in rear cabin temperature was 16.5deg C. It was clear that the Duster’s AC performance got stronger as the speed built up.
2. Tata Sierra front and rear AC performance
The Tata Sierra’s dual-zone automatic climate control system lowered the front cabin temperature by 9.2deg C in one minute of idling. At the end of 5 minutes of driving, the Sierra’s cabin temperature at the front fell by another 6.5deg C – a total drop of 15.7deg C since the test commenced. By the end of 16 minutes, it was 18.2deg C cooler than at the start.
The rear cabin temperature at the beginning of this AC performance test was already lower than the front by 5.2deg C. Over the next minute, with the climate control system set to its coldest setting, the cabin temperature at the back fell by 6.3deg C. After 5 minutes on the road, the rear cabin got cooler by 4.9deg C since the one minute of idling that preceded it. The lowest recorded temperature at the rear of the Sierra’s cabin was 31.5deg C, indicating an overall drop of 13.5deg C since the start of this test. We also noticed that the blower strength was good, spreading cool air throughout the Sierra’s cabin effectively.
*Front seat temperature measured near the driver’s ear; rear seat temperature measured at the centre armrest.
Dipan Sur
Uday Singh
Saptarshi Mondal
Viraaj Bhatnagar
