Next time you get into a brutally hot vehicle that's been sitting in the sun, be sure to thank the inventor of car air conditioning. It's an amazing system that effectively creates comfortable cabin temps, but we all have that one friend or relative that refuses to use air conditioning since "AC lowers my fuel mileage."
Does AC use fuel?
This question has an easy answer. Yes, air conditioning, and anything else that draws power from the engine, uses fuel. The less easy question is: Why?
Air conditioning uses fuel because it is a system directly connected to the vehicle's engine. Anything that draws a load from the engine, such as spinning the water pump, alternator or AC compressor pulleys pulls engine power, in the form of additional fuel, to operate the accessory. In this way, think of everything from your radio and headlights to your AC system as using fuel. There's no easy way to say exactly how much fuel the AC system uses without precise testing. Factors that will determine how much fuel the AC system uses are the age of the vehicle, condition and previous maintenance of the AC system, and the load setting used (the maximum setting obviously requires more energy than the minimum setting). Even among vehicles of the same class, manufacturers might use entirely different AC equipment.
Tips for improving fuel consumption (even with the AC on)
There are several ways that may help maintain or improve your fuel mileage, even while you're making it cold inside your car.
- Check your tyre air pressure
If that low tyre pressure warning light is on and you keep driving, you're burning money. Reduced tyre pressure lowers fuel economy by 2% to 3%, with more impact at lower speeds. Low pressure also increases wear on the tyres, and results in negative handling and stopping ability.
- Use the recommended engine oil
If your owner's manual recommends 5W-30, and you pour in heavier 10W-30, your fuel economy will suffer by 1% to 2%.
- Get an alignment when you get new tires/wheels
Any time you notice symptoms of misalignment. The camber, caster and toe all determine which direction the wheels are going and being even a few degrees out of spec can negatively impact fuel economy by as much as 10%. Yes, this one also wears out the tyres early if you don't keep up with proper alignment specs.
- Have a pro apply window tint
Sign up for free AllAfrica Newsletters
Get the latest in African news delivered straight to your inbox
This thin layer of film provides heat and UV reflection, so the heat doesn't enter the cabin in the first place. A vehicle with quality tint can reduce cabin heat by 43% and won't need to use as much AC to stay cool.
- Plan your trips for higher speeds
AC at idle uses noticeably more fuel than at highway speeds. If your route has highway and city streets available, aim for higher speeds and reduced AC fuel consumption.
- Drive with the windows down for the first minute
- This quickly evacuates the hot air from the cabin, putting less demand on the AC system.
Nelson Xavier Ssenyange
Team Leader
Germax Autos, Spares & Garage Ltd
Lukade Road, Naalya
0779250886/0752088734
