I’ve had my car for less than a year. During the Winter, I often had on the heat and the rear defroster. Come springtime, I found out just how much gas those two were guzzling. I’m now getting close to seventy (!) miles more per tank when there’s just a vent or the windows are rolled down. That’s a savings of around $5 every tank. If we assume I fill up every week, it’s a savings of $260 every year. Plus or minus depending on milage driven and gas prices, but still a good chunk of cash.
So would you forgoe the comfort of heat or AC to save that cash? If not, how long would you last? Me, I think summertime would be no problem. Wintertime I’d probably need the heat on, but maybe turning the knob all the way to the right. Maybe I could last all Winter, but it seems that $5 isn’t that much to spend to stay comfortable.
No a chance in this environment (Jacksonville, FLA) Despite what the Chamber of Commerce says about our “average” temps, it is common for there to be several days in a row of 90-95+ temps with 90-95+ percent humidity. After your car has been baking on an asphalt parking lot all day, driving without A/C is a health risk. Sorry.
On the other side, winter lows sometimes get into the 20’s, usually 30’s. With appropriate gloves and coat, I could probably tough it out.
I almost never use AC when driving, no matter how hot it is. The only exception is if it’s 95°+ and I have to wear a suit & tie and have a snazzy hairstyle (i.e. I’m going to court) then maybe. Otherwise I let the 95° wind blow through my hair as I drive, so what if I perspire a little.
I could understand constant use of AC if you have respiratory conditions or sit in b-b traffic and don’t want to breathe smog for 20 miles, but not “just because it’s there”.
So I would answer this from a different angle- I would not turn on the AC (or heat) because I don’t need it as much as others seem to, and because I don’t want to burn up any more fuel than necessary.
Ender, if you are getting much better mileage without using the heat, something’s wrong. Unless you own a Corvair or old-style Beetle with a gasoline-fired heater, using the heat doesn’t make that much of a difference.
Automotive heaters in cars with liquid-cooled engines scavenge heat for the passenger compartment by running the coolant used by the engine to keep from overheating during operation through the heater core (a mini radiator) on the cowl. The heat is distributed by circulating air through the core to the interior of the car via a blower. Although the blower is electrically powered, it doesn’t draw enough electricity to deplete your driving range by seventy miles. And there’s no extra fuel used to create the heat; it’s waste heat from the engine that would be expelled through the radiator if you didn’t divert it for use in the passenger compartment.
If you have a grid-style defroster (as opposed to a blower for the rear window), it draws electricity to create resistance in the painted-on window grid which generates heat to defrost the glass. However, it shouldn’t draw so much electricity that its use would cut your mileage like that.
Have you done any maintenence on your car lately? A recent tune up and/or inflating your tires to the correct pressure will improve your mileage (although not that dramatically, I’d think). But if your car is using that much more fuel in colder weather I’d have it checked out.
Just my $.02. . .
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For the record I use the heat or A/C whenever conditions demand it. Although it’s nice to drive around with the windows open, a 2% mileage reduction is a small price to pay for comfort and quiet IMO.
“On the other side, winter lows sometimes get into the 20’s, usually 30’s. With appropriate gloves and coat, I could
probably tough it out.”
I don’t mean to mock your pain but if winters here were that warm I’d consider wearing shorts.
Ender - Your fuel mileage in the winter decreases because there is more warm up time than when the temeratures are warm, running the heater should have no effect unless you have a gas heater as Zappo described.
On the other hand, the AC draws significantly more power as the belt is attached to the crankshaft pulley. Fire up the AC while your car is in motion and you can often feel it drawing a few HP.
I don’t find that I lose that much mileage running the AC in my car as I have an automatic thermostat, the AC will turn itself down on it’s own once the interior hits the preset temperature. The fact that the interior of my car is compact makes a difference in that it doesn’t take long to cool things down.
Our van takes a long time to cool down due to the size of the passenger compartment and the amount of glass area. With small children the AC is essential, it makes them so much happier to not be baked as we travel. I lose a little mileage but it’s worth it to be comfortable.
Zappo, you’re right. There’s a good chance that there’s something wrong with my car. Last year I was getting around 260. When Winter hit I was lucky to get 240. Now that Spring is here I’m easily getting 300 with room to spare. I have no clue why this is so but I assumed it was the heat and defroster (grid style).
My car is a 2001 SC2 Saturn and it’s supposed to get 25/35 MPG on an 11 gal tank. That’s why I’ve been quite upset with 220-240 miles/tank. 300 is much better, but I’m dreading next Winter.
Ender, how many miles do you have on your car? Your winter mileage sounds a bit low, but the current mileage seems pretty decent. Feynn is right about the mileage being lower in the winter because the engine takes longer to warm up. Your mileage will vary a little bit due to weather conditions. The difference between your range last year and over the winter sounds normal, but a 7 MPG spread between winter and spring is a bit too wide unless you’ve just quit driving with a lead foot or removed your brick collection from the trunk. My experience has been that mileage per gallon drops about 1-3 MPG during the winter.
IIWY, I’d take the car in to the dealer and ask them what’s going on. Have them check the car out and while it’s there have them do the recommended service. Tell them that you’re happy with the car but the increase in mileage seems a bit drastic to you. At the very least, you’ll get the car back washed and vacuumed.
BTW, if the 25/35 MPG figure is what appears on the window sticker and/or in the literature don’t take it too literally. Those numbers are generated using the EPA’s test standard, which involves running the car on a dynamometer in a “programmed test loop” that resembles real driving only in that both involve the operation of motor vehicles. YMMV (literally!) and is usually 10-15% less than what the carmaker posts on the sticker.
In our area, they add ethanol to the gasoline in the winter, and change back to their ‘regular’ formulation in the spring, supposedly to alleviate pollution in the winter. It’s been somewhat controversial, because of the reduced gas mileage of the winter formulation. Do they mandate that in your area, Ender? That could contribute to your mileage discrepency as well.
I don’t notice an appreciable difference in mileage through the year (vehicle most often driven: 1995 Nissan extra cab pickup, 96K.) I do know that driving at highway speeds with the window down creates drag & reduces mileage; how this compares to using the AC, I don’t know. Also, when it’s cold, warming a car up for a looong time before driving it is not only unecessary, but pollutes & over the long term can be bad for the car (am I right, Zappo?) I’ve always heard best to let it warm up by driving gently for the first several miles.
As to the OP: Heat when it’s cold out…absolutely. AC? I don’t mind heat, so often don’t use it. However, I’m in construction. When I’ve spent all day doing physical labour on ladders & roofs in the hot sun, you bet your ass I’m enjoying the AC on the way home! A couple of hundred bucks a year is a small price to pay.
Right on the money, Carina. It’s not necessary to warm up the car for a long period if you’re driving a modern fuel-injected vehicle. Usually, a minute or so is long enough to get oil to the top end of the engine and get things freed up. Beyond that you’re just wasting gas. On cold mornings start the car first and then let it run while you buckle the seat belt, check the mirrors, turn on the radio, etc. After that, driving gently for the first several miles allows the car to warm up gently and gets things going.
The old “start it and let it run for awhile” rule is good advice for older cars with non-electronic carburetors. Allowing the car to sit still and warm up in that case gives the choke time to lean out the fuel mixture. That way you aren’t driving with an overrich fuel mixture, which can hurt your mileage and is rough on the engine. Modern fuel injection systems don’t need time to do this because they use computers to adjust the fuel mixture faster and more often than a mechanical choke can.
I’m with Zappo on this one. I have a plain carborated engine, and when it’s 0 degrees out the car has to warm for five minutes to drive above 25 MPH without a lot of wasted gas.
You have to warm up the car in the winter long enough to get the window defroster hot enough. You can leave with the windows clear as soon as you start the car. One block down the road and the wind blowing over the clear window combined with the moisture in the air. will frost the window over. Zero visablity on unplowed roads at pre-dawn is a big problem. You then pull off the road, and wait 5 minutes on the shoulder as the defroster warms up. I don’t know if people in other areas have this problem? It’s below freezing and there is fog in patches on the roadways. Your windows ice up right away unless hot air is blowing on them.
I just remembered the warm-up instructions in “Idiot’s Guide to Volkswagen Repair.” Start car. Roll a cigarette (nudge nudge wink wink). By the time you’re done rolling it, the car is sufficiently warmed up to drive off slowly. Being a VW, slowly is a given…
A pet peeve of mine is people who leave cars idling for 10-15 minutes on cool mornings. I run my dogs in the morning, and hate having to breathe the nasty fumes as one or two cars are idling away on every block. I’m in Denver, so it’s not like we often get bone-chilling cold. I have a '67 Plymouth that needs a minute or two to warm up before driving, otherwise it will die at the first several intersections. I never knew it was because the carburetor needed to adjust, thanks Zappo.
Harmonious, I imagine if it is below freezing and humid & foggy, that could warrant longer warm-ups! It’s so dry in Colorado, this is rarely a problem.
You’re welcome, Carina. A '67 Plymouth, huh? I knew you were a person of refined taste and good manners. Now that you’ve learned something new, take the rest of the day off. Tell 'em I said it was OK.
Yep, humidity and fogging require longer warm-ups. It doesn’t hurt the car, it just leaves you getting 0 MPG because the car is idling. I live in Pennsylvania, where our cold days are often damp. If I’m driving one of my cars that’s been outside overnight it has to run awhile so that the defroster can heat up enough to keep the windows clear once I get underway. It’s no big deal, usually I just start the car and then scrape the ice and frost off the windows while the car idles. It only takes a couple of minutes, and once you’re done with that the car is usually ready to go.