[gambiting]

But......EVs do work in cold weather? You lose a bit of range, but so what? My ICE car also gets worse mileage in winter.

And if you're talking about extremes - then there's a reason why block heaters with external power connections are very common in certain places - even the best ICE struggles to start in -40C or less.

[letitbeirie]

At those temperatures you're up against the flash point of gasoline, which is already the lowest of any (liquid) fuel I can think of.

[BenjiWiebe]

Remember that compression raises the temperature.

[simfree]

18Mpg becomes 10Mpg or worse in the winter in my experience. EV driving can be more efficient if you don't let your battery cold soak for hours, or equally inefficient if you do leave your car unplugged overnight.

[TedDoesntTalk]

I live in place that routinely goes below freezing in winter. I’ve never noticed gas mileage change because of temperature. I would definitely notice a difference of 8 MPG. Where do you get that info? Is it personal experience? If so, where do you live?

[gambiting]

I easily notice the difference in my car, it goes from about 8L/100km in summer to 10L/100km in winter. That's on the same tyres in both seasons.

[bch]

Driving through snow?

[gambiting]

No, just driving on the motorway, at a solid 140km/h. Did the exact same drive in winter and in the summer just this year and that was the difference in consumption(I want to add that I can see the difference in daily use too, but I just happened to do the exact same 700km drive where the only different factor was the season of the year, so it gave me a very good reference point for specific numbers).

[adrianN]

It's even worse for city drivers doing short trips. The engine doesn't have time to heat up properly before you reached your goal. Fuel efficiency is abysmal and the exhaust treatment systems barely work.

[kevin_thibedeau]

Cold air is denser. Pushing it out of the way saps more energy and drops the effective work done. You're oblivious to it because a motor vehicle has so much available power on tap. It is very noticeable on a bicycle at high speeds.

Conversely. Sailboats get more efficient in cold temperatures because more energy is imparted on the sail.

[bumby]

>Cold air is denser. Pushing it out of the way saps more energy

ICE mpg tends to drop in cold weather, but this isn’t why. It’s usually because it takes longer to reach optimal operating temp or due to changes in fuel composition. Cold air can produce more drag but that problem exists irrespective of ICE or EV.

The pumping efficiency is unaffected as any losses on the exhaust side will be offset by increased pressure on the intake side.

[scott_siskind]

> It is very noticeable on a bicycle at high speeds

Huh? I've been cycling for 15 years, many of those years doing 15k km a year, all year round. Mountain biking on mountains at -15C, down to urban cycling in 38-40C scorching summer heat. I've never noticed speed, effort, stamina changing with temperature as you suggest.

And I've done lots of road cycling at constant 35-40km/h, descents of up to 70+km/h.

[pastage]

I am not really contradicting you here. Just want clarification from GP. My reaction was Huh? As well.

With N=15 years of gps data and 40-70 of those days per year below zero very few below -10°C. I can say that I ride slower on cold days on avarage.

I am not fit and do not track that at all. I can barely keep my avarage above 25km/h in city traffic for 15km, very few conflict points maybe twenty but not comparable to road cycling. So a km/h decrease of avarage speed during winter is common but not a given. I do not count bad road conditions, but Stockholm has really good maintanance during winter, ice free asphalt all year.

[Lio]

I definitely ride slower in winter too but I always assumed that was due to my body having a harder time in the cold rather than air density changes.

That seems to be born out by using better (read more expensive) winter riding gear. I naturally run a bit cold so spending on low temperature tights, base layer and jersey/jacket has made a massive difference for me.

[LargoLasskhyfv]

More wind chill? More weight by thicker clothing?

[bennyelv]

Interesting! I’m also a long time high volume cyclist, and I see a clear effect of slower rides in winter. I’m talking about around specific routes and training sessions where the point is to go as fast as possible. With the same power I seem to go more slowly when it’s cold.

Obviously there could be many reasons for this: less aerodynamic clothing, more cautious cornering etc etc, but the effect is very noticeable to me.

[kevin_thibedeau]

Track your time on a consistent route on paved, snow free roads. I guarantee you'll see a dip in winter.

Scorching heat with high humidity has an opposite effect. H2O drops the density of air and you can go measurably faster than in drier air.

[Manuel_D]

Colder air's increased density and bigger temperature gradient also improves the efficiency of internal combustion engines.

Increased rolling resistance from displacing snow is a far bigger cause of winter driving inefficiency.

[trentgreene]

Hmm, I wonder if the increased resistance is overcome by the fact that ICEs can put out more power with colder denser oxygen rich air.

This is why performance cars sport cold air intakes. This is also why your car won’t hit its quoted 0-60 time in a warmer environment — those tests are normally performed or normalized to cold air conditions + 0% humidity. Just what counts as cold depends on manufacturer / reviewer.

Anecdotally, I track efficiency and drive consistent routes, and don’t notice a diff.

[bumby]

I wonder if the increased resistance is overcome by the fact that ICEs can put out more power with colder denser oxygen rich air.

Not likely, as an increase in air is going to be accompanied by a corresponding increase in fuel. Unless your fuel mapping is all messed up, it will give you more power, but not likely better fuel economy.

[eldaisfish]

this is the textbook definition of confidently incorrect.

Winter fuel efficiency is worse because of a winter fuel mix, not because of air density.

[dgacmu]

And if you don't pump up your tires to compensate, the lower pressure from cold temps will increase your rolling resistance. Not a 40% drop but enough to notice if you're tracking mpg.

[thaumasiotes]

> You're oblivious to it because a motor vehicle has so much available power on tap.

Dropping from 18 mpg to 10 mpg would increase your cost of fuel by 80%. It'd be hard to be oblivious to it.

[Gordonjcp]

> Cold air is denser. Pushing it out of the way saps more energy and drops the effective work done.

That makes absolutely no difference at all.

[sokoloff]

> That makes absolutely no difference at all.

That would be very surprising if it were true, given the very large effect density altitude has on airplane performance (engine and wing).

[maxerickson]

It's gonna make some difference, but air resistance goes with square of speed and the change in density due to temperature isn't that large.

[Gordonjcp]

Over what sort of range of height and pressure?

It's just about observable with very light and very aerodynamic aircraft at ground level if you can get them cold enough.

[simfree]

Here in the Pacific Northwest, driving both last winter in BC and currently in the mix of snow, freezing rain and slush. I'm using the same three peaks rated all season tires as I was using in the summer, and driving the same routes as well.

[marginalia_nu]

In colder climates, it's common to have an engine block heater, which to some extent mitigates this. A significant chunk of the lost "mileage" is from cold starts.

[BenjiWiebe]

Something must be wrong with your vehicle. I've tracked every tank of fuel I've put in either of my vehicles, and the efficiency does drop in the winter, but nowhere near that amount.

I actually just looked at my economy graph, and I can't tell how much winter affects it. The variance is less than the variance of my driving habits. So less than 20%.

[kevin_thibedeau]

Got it. So just make sure your vehicle is constantly consuming energy and you'll never have an issue... unless the power is out for an extended period of time.

[tshaddox]

If the power is out for an extended period of time you’ll find gasoline hard to come by as well.

[EdwardDiego]

Want to see how quickly the petrol supply line breaks down in an emergency? We had severe shortages for a month after an earthquake. People hoarding fuel contributed significantly, at least you can't hoard electricity.

Also, electricity supply isn't prone to supply shocks when Russia invades Ukraine, or the Saudis want to flex their muscles.

[gambiting]

You never started your car and just let it warm up before setting off in winter? How much energy do you think that uses?

[simfree]

Letting the car consume a small amount of constant electricity to keep the battery above freezing is thankfully not very expensive compared to a standard space heater (usually 1.5kW at 720 hours a month, costing $150 a month in Seattle).

Defrosting and toasting the cabin to 92F in freezing conditions usually burns about 1.2kWh to 3kWh while plugged in, but that is just a few tens of cents (or free depending on the charger) to get nearly instantly toasty and ready to drive.

[alphabettsy]

$150/mo just to keep it ready to drive? That doesn’t sound right.

[simfree]

No, I was trying to convey that it costs significantly less than keeping a space heater running 24/7 (which would cost about $150 a month at 14 cents per kilowatt hour).

$10 to $30 a month in power use to keep your battery toasty in the dead of winter isn't too bad a price IMO

[kevin_thibedeau]

No. That's a waste of a useful resource. It's also illegal in various places.

[simfree]

Driving with an iced over window impairing visibility is illegal in most places, you have to address this with defrosting and perhaps scraping before moving the vehicle.

Idling combustion vehicles is bad, but sometimes it's a necessary evil to ensure visibility so the driver can avoid harming other road users.

[avar]

> Idling combustion vehicles is bad.

Not really, you're spending a fraction of the fuel you'd use per minute if you were driving.

So, in terms of pollution it's no worse than taking a short detour to wherever you were going.

[gambiting]

Well, I envy wherever you live then, must be nice in winter!

[kevin_thibedeau]

It's 13F right now. I can afford clothing.

[skhr0680]

In city driving my ICE gets 6-8km/L in summer and 8-10 in winter. On the highway it gets 10-12 in either season

[midasuni]

18mpg is 21mpg with U.K. gallons. My fairly large Skoda gets 45-50 in the real world, maybe dropping to 42 if I’m pushing it to 85mph on the motorway.

Even back when I owned a mid 80s Nissan around 2000 I was getting 25mpg (us gallon).

Why is US mileage so awful?

[simfree]

Large SUVs with overcooked engines to meet emissions requirements (lower PM2.5 emissions at the cost of slightly worse fuel economy) get bad mileage.

Having all wheel drive or 4 wheel drive, high ground clearance, a poor aerodynamic design (driving 70mph or 80mph sounds bad in many of these cars) also hurts efficiency.

[Scoundreller]

Even when it comes to cars, often the US base model has a larger engine than the EU base model.

No idea why: speed limits are often higher in EU and often with more hills.

[avar]

It's because in addition to fuel being cheaper in the US, many EU countries tax you on engine displacement, CO2 emissions, fuel economy etc.

[gambiting]

Well yes, but watching American car reviews(as European) leaves me puzzled - reviewers often describing 3.0L V6, 200bhp engine as small and low power, and discussing if it's not dangerous to merge on the highway with it, while over here you get a 1.0L 110bhp engine in a large family SUV and it isn't even brought up as an issue. In my last car the base option was 90bhp, and the "high performance" model was 160bhp. I guess in US that would be described as a horse cart. That's despite the fact that even the 90bhp model had no issue keeping up with 80mph traffic.

[SamBam]

18mpg would generally be a pickup truck. You'd be hard-pressed to find a regular sedan that has mileage that bad.

[lelanthran]

> 18Mpg becomes 10Mpg or worse in the winter in my experience.

That sounds like nonsense. What were you driving that had such a reduced mileage?

[jhoechtl]

Yeah additional electric heaters and stiff oil reduce mileage but Nowhere in that range.

Your car must be faulty.