Honda’s Econ button is a clever way to force you to control your throttle response, shift pattern, and AC for maximum fuel economy.
If you’re a Honda owner with a car newer than model year 2008, you’ve probably used that green button labeled “Econ” in hopes of using less fuel to save money.
In newer Hondas, Econ is a dedicated driving mode.
You’ve probably also noticed, with “Econ” mode on, sluggish throttle response, early shifts, and an air conditioner that cycles less and blows not as strong.
This is all by design to achieve, in Honda’s controlled study, up to 9.5 percent reduction in fuel used compared with the button off.
But what exactly happens behind the scenes of “Econ” mode to achieve those fuel economy gains?
Honda initially developed Econ mode for the MY 2009 Honda Insight and have since transferred that same technology to the rest of its lineup.
Honda actually wrote a research paper titled, “Technology for Increased Fuel Efficiency in New INSIGHT” that goes into great detail how Econ mode works.
According to their paper, here’s exactly how Econ mode works.
Optimized CVT and transmission shift patterns
It’s common sense, a car uses more fuel as engine RPM increases.
Treating the accelerator pedal aggressively also causes early transmission up-shifts, which increases engine load and RPM as you speed up and uses more fuel.
Honda illustrated transmission efficiency is inverse to RPM (as RPM increases, transmission efficiency decreases.)
If Honda’s ECU can force you into a shift pattern that maximizes fuel economy, despite hard stomps or repeated presses of the accelerator pedal, fuel efficiency gains can be achieved.
Keeping in mind the previous statement on efficiency, the most gains are found keeping you in the lower RPM range as much as possible until you reach your desired gear.
So with ECON ON mode,
“The shift response coefficient is reduced, thus reducing the speed at which a down-shift occurs when the accelerator is depressed.
This helps prevent the engine speed from inadvertently rising when the driver depresses the accelerator roughly, thus facilitating high fuel economy driving.”
What this means for the driver is in the lower RPM range, if you aggressively stab the gas pedal, with ECON mode on, you won’t immediately downshift.
When you press the accelerator pedal you are mechanically or electronically opening the intake throttle from 0% (closed) to up to 100% (open aka wide open throttle)
From there, your ECU determines how much fuel to give. More air, more fuel, more power.
If you can be forced into a throttle percentage range, despite large and rapid depresses of the gas pedal, fuel efficiency gains can be achieved.
Honda illustrated that most gains of fuel efficiency come from quick accelerator operation as opposed to slow accelerator operation.
If you depress the gas pedal slowly, with ECON mode on or off, there’s no difference in throttle control.
It’s only when you do “Quick accelerator operation” does Econ mode come into play.
In the Insight’s case, even if you stab the accelerator pedal quickly to a 40% position, with Econ mode on, the throttle will only open half as much.
What this means for the driver is throttle response will be dulled significantly in high-power situations (merging, overtaking, passing etc.)
Air conditioner control
AC compressors exert an engine load, more so at lower engine speeds and when outside temperatures are extremely high.
Econ mode controls Air Conditioning by limiting how long an AC compressor runs, how hard it runs, and how many times it’s engaged, thus reducing AC use and fuel.
Honda’s Econ mode achieves this by,
- When outdoor temps are high, internal circulation and air intake load by controlling fan speed is reduced.
- Reduction in the frequency of the air conditioner clutch.
For the driver this means, with Econ mode on it’ll take longer to achieve lower in-cabin temps but you’ll save a bit of fuel.
Since this paper was published, it looks like Econ mode now includes fuel injection control.
There is a margin of fuel that needs to be injected under different circumstances to allow your vehicle to perform properly. Pressing the Econ Button reduces the fuel injected inside your engine to the lesser of the margin, which effectively helps to use less fuel.
Real world fuel economy gains examples
With Econ mode on, Honda claims a 9.5 percent reduction in fuel used for the Honda Insight. But what about other cars?
2022 Honda Civic – “In Econ mode, I got about 38.6mpg. Normal driving I got around 35.6mpg. So 3mpg benefit, which let’s just round it off and say it gets you about 10% efficiency boost if you play it right. That’s actually a very impressive gain, that just pressing a button gives you a 10% benefit.”
2018 Honda Ridgeline – “ECON ON: 21.0 mpg ECON OFF: 20.6 mpg. Projected savings with ECON over one year: $3 gas, 15K miles under the same conditions, $42”
2018 Honda Accord Hybrid- “Now, 10.2 miles is not enough to be really certain about the difference between ECON (55.0 mpg) and NORMAL (54.1 mpg).”
2017 Honda CR-V Touring- “I consistently average 29-31 mpg in normal driving – a mix of mostly around town with some highway driving. I noticed the mileage seemed to drop when I engaged ECON. Last fill-up, I turned ECON on and my mileage dropped to just over 25mpg.”
Honda Econ mode reduces frequent, on-demand up shifts, dampens throttle response, reduces AC load, and reduces the amount of fuel injected under certain high-performance situations.
Keep in mind Econ mode can become a safety issue if you need power (e.g. if your commute requires lots of freeway merges, you need to speed up quickly often.) In those cases, keep Econ mode off.
Looking at real world examples, there are MPG gains to be made.
It looks like most of those gains come from city driving as opposed to highway. If you’re a level-headed driver who mostly drives around town, Econ mode CAN save you a couple bucks in the long run.
If you take frequent out-of-town trips, commute long distances daily, or rely on power as much as possible (carry lots of loads, the school run) keep Econ mode off.