As the temperatures drop in cold regions of the country, so will average miles per gallon.
It’s a fact of physics, what cold does. According to the EPA a conventional internal combustion powered car that gets 30 mpg in 77 degree (F) weather will see it drop 12 percent to about 26 mpg in 20 degree weather. For the first 3-4 miles before it warms up it can get 22 percent less efficiency, or as low as 23 mpg.
For battery dependent hybrids, the EPA says a 31-34 percent decrease is not uncommon. That would mean a Camry Hybrid that might ordinarily get 41 mpg could drop to as low 26-29 mpg in 20-degree weather. And that’s assuming you are not slipping and sliding on snow, which would waste more energy.
As always your results will vary, there are a few things you can do to at least compensate, but before we get to that let’s talk a little more about mechanical realities.
Like humans, cars like it balmy. The combined effect on the car’s components all add up to decreased energy efficiency.
For example, engines and transmissions experience increased friction when the oil and other drivetrain fluids are not warmed up.
Engines operate best at a certain temperature range, and cold means it will take longer to reach that ideal.
Just using the heater, defroster, or accessories like heated seats takes energy, and affects mpg.
Even wind resistance increases, especially at higher speeds. Cold air is denser, and it has a marginal influence as well.
That same dense air also can reduce the pressure inside tires, and this in turn yields increased rolling resistance.
And last but not least, batteries don’t favor the cold, and for conventional vehicles this means the alternator has more work to do, and hybrids’ regenerative braking has less effect.
What to do
If not there already, you could move to some place like Florida, the south coast of Texas, California, or another place with less severe winters.
If that’s not a good solution for you, a few pointers following may help. They should be considered additions to basic economical driving practices you’d normally want to do.
While these are primarily for vehicles with gas engines, including hybrids, plug-in hybrids, and conventional vehicles, some details apply to EVs as well.
Combining trips, and planning your route will mean fewer miles traveled, and less gas or energy use.
Keep Vehicle Warm
If staying in and drinking hot cocoa is not an option, having the car parked in a warmer place like a garage will help – assuming the garage is warmer than outside.
This means the engine warms up quicker and the interior of the vehicle also does not have to be brought as much up from frigid temperatures by your heater.
Don’t Warm Up Overly Long
Some people may start their vehicle and leave it running with the defroster and heater blasting in freezing weather, but that uses energy while delivering 0 mpg.
Check also with your vehicle owner’s manual, but most manufacturers say a quick 30-second or maybe longer warm-up will get things circulating, then an easy start will warm things faster.
As things warm faster, the heat from the also-warming coolant will work better sooner as well.
Reduce Frictional Losses
If you have a kayak or bike rack, or the like, and aren’t planning on doing your sport in freezing weather, remove them. These and ordinary roof racks increase wind resistance and sap energy.
Checking tires periodically to ensure they are to proper pressure is also important.
Plug-in hybrids and electric cars will save energy if preheated while still plugged in.
Seat warmers usually take less energy than warming the entire cabin with the heater.
Watch That Snow
Slipping on snow or ice will also mean the powertrain provides energy to spin the wheels faster than the rate of travel, so that too means decreased mpg and increased emissions.
If you have selectable all-wheel drive, that will increase fuel consumption as well. Using it only when needed is advisable.
Be Mindful of Oil an Gas
Changing the engine oil to a viscosity recommended by the manufacturer, as applicable, will help.
Winter grades of gas however do have somewhat less energy value than summer grades, so this right here may mean a slight mpg decline you may or may not notice.
The Cold Facts
As you can see, short of staying home, some realities are unavoidable, but they can be mitigated somewhat.
Hopefully these tips may help, and stay safe!