By on June 11, 2012

That huge sunroof on top of you greenhouse could cost you more than just a few extra $$$$. It could ruin the car’s mileage, says a new report. “Automakers may be obsessed with cutting vehicle weight,” writes Automotive News [sub], “but they are happily packing on pounds in one place.” Those added lbs will mean increased gals, and not the female kind.

Cars like the 2013 Lincoln MKZ, or the Cadillac’s SRX crossover sport sunroofs that come close to the size of a Japanese starter home. “The glass can add several more pounds than steel, depending on the size of the opening,” says the report. “And an open sunroof interrupts airflow over a vehicle, increasing drag and reducing fuel economy.”

Automakers already carefully monitor the take rates of those skylights:

“If the heavier sunroofs make up more than a third of a vehicle’s production mix, the vehicle’s fuel-economy testing must include the feature.”

 

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56 Comments on “Huge Sunroofs Can Burn You At The Pump...”


  • avatar
    thehomelessguy

    Don’t know about the weight, as cars are already quite fat around the middle, but the cooling factor can definitely decrease the fuel economy. Take a car with start/stop function for example, if the AC needs to run they will keep the gas engine going when normally it would shut off. This is also true of true hybrids. I doubt you’ll see any sunroofs on electric cars/plug-in hybrids anytime soon.

    • 0 avatar
      jberger

      The Prius and Camry Hybrids are all electric accessories and provide AC or Heat even with the ICE is shut down. Stop/Start has no effect on the availability of accessories since they just pull from the battery when sufficently charged.

    • 0 avatar
      protomech

      Tesla’s Model S has an optional panoramic full-glass roof.
      http://www.teslamotors.com/models/features#/styling

      3rd gen Prius has had a moonroof since 2010.

  • avatar
    indi500fan

    When I bought my first gen SRX, I looked a long time to find one without the Ultraview. Was riding in one when it imploded, and it’s a real thrill, suddenly you have 100,000 marbles of glass in the interior.

    Then comes the fun. GM says it’s caused by a road hazard and covered by insurance, and the insurance company says it’s faulty glass and should be warranty.

  • avatar
    racingmaniac

    Haven’t owned a car with sunroof yet…actually for my current car I specifically got one without….

    Glass is heavier than steel, opening reinforcement weighs more, motor mechanism adds weight, reduced head room. And all the additional weight is on top, raising CofG…seems like a lose-lose thing to me…

  • avatar
    Felix Hoenikker

    I never get sunroofs since they interfere with the appearance of a beautiful vinyl roof.

  • avatar
    NormSV650

    What about those rear, trunk lid wings?

  • avatar
    Sundowner

    huge sunroofs suck for a number of reasons like the fact that large expanses of glass have different thermal properties than the surrounding metal, which in a moving structure, means large body gaps, creaks, leaks, poor operation, and eventual failure. Tehy also shift the car’s center of gravity up, force more metal to be put into the body structure to both carry the weight and replace the lost stiffness of the missing steel roof, and (this is a pet peeve) a lot of these monster roof panels have perforated rolling retracting shades that don’t block all of the sun, which is obnoxious on hot sunny days.

    • 0 avatar
      Caboose

      I have never had a sunroof that hasn’t eventually leaked during my ownership. I am currently really drawn to the latest Charger in part because I found out (I think) that I can get a V8, rear-driver with heated (for the wife) and cooled (for me) seats and no sunroof at all if I spec it right and if the website isn’t lying.

  • avatar

    Got to love the “take rate” trick that keeps MPG-impacting options from affecting the numbers on the window sticker.

  • avatar
    Chocolatedeath

    The big roofs dont bother me at all.. I am a sun roof lover and cant wait to see the MKZ in person. Besides what does a sun roof subtract from mileage anyway?? 1 on the hwy and city maybe. Never really seen numbers broken out like that. Sun roofs are like hybrid options they are either hated or loved by those on both sides. However Hybrids soon wont be an option but a staple in most cars in the next 15 years.

  • avatar

    The real weight increase is not the glass but rather all of the steel required to reinforce the top of the car to make it strong with the sides. Certainly this extra 100-200 lbs. is enough to impace gas mileage.

  • avatar
    npaladin2000

    The “take” rate on them is high because a lot of cars require a sunroof in order to get most of the other desirable options.

  • avatar

    People buying a $45,000 Lincoln when they could have purchased a $35,000 Ford DON’T CARE.
    It’s a mindset that says “I can afford to drop $60 a fillip on Super Premium Unleaded”.

    The option: Don’t get the roof and have less to show off.

    • 0 avatar
      highdesertcat

      Exactly! MOST Americans don’t care about the price of gas. What they do care about is to see and be seen.

      During a recent trip to NYC to visit my brother in Manhattan, I was amazed to see so many vehicles with glass roofs, not something we readily see in the sun-baked, wide-open spaces of New Mexico where I live. For one thing, a glass roof in New Mexico would facilitate you getting cooked much more rapidly while on the road.

      And these were not all luxury cars in NYC either. Many of them were just plain old everyday Joe Sixpack Ford and GM products.

      • 0 avatar
        Wheatridger

        Well, maybe in Manhattan’s concrete canyons, there’s more to see up there. Plenty of shade, too…

      • 0 avatar
        highdesertcat

        That’s what I was thinking too, although I didn’t see anything there worth seeing that held my interest.

        I guess it takes a special kind of people to live in such densely populated space. To each his own.

        And maybe that’s why I’m not surprised that so many people from ‘back East’ are cashing out and moving to the wide-open spaces of the Southwest, and buying property with some open space to keep from smelling the next person.

      • 0 avatar
        golden2husky

        Actually there is a lot to see. I’ve traveled out west for 20 plus years, primarily for skiing, and likely will retire there or New England. Once you get used to the altitude, and the brown(er) earth tones there’s a lot to like. I’d take the mountains over the beach any day. But if you are into man made scenery, you’ll be hard pressed to find a more fascinating place than Manhattan. Yeah, if crowds bug you, any large city is not for you, but people watching has its charms as well. The density of hot women is hard to beat! Just checking out the women of the Brooklyn Bridge Boot camp doing their morning training on the bridge walkways actually makes sitting in traffic pleasurable.

      • 0 avatar
        highdesertcat

        It’s brown where I live in the high-desert but the backdrop is the Sacramento Mountains, so I can experience four seasons within a half hour or thirty miles. Plenty of greenery going up the mountains.

        Trouble with all the forests and all the greenery is that it is also fuel for lightning-started forest fires. And we do have those.

        And hot women? With all the colleges and ski slopes, they come from all over.

        The people I know who came here from the East did so because they wanted to get away from crowded living and other people. Some have pursued their dreams here with fewer restrictions while others have found new, meaningful hobbies AFTER they retired from their careers.

        Some retired guys from the East started vineyards and wineries, pecan farms, horse sanctuaries, animal sanctuaries, trout farms, cherry orchards, and a bunch of other interests I can’t even recall, after they got here.

        But I would not recommend huge sunroofs in the desert.

    • 0 avatar

      Here in Manhattan, the hot women don’t really care about your luxury car unless it’s an exotic. The German cars own the streets here, but, they are all used as limos. There are like 100 S550’s per city block (makes me feel bad sometimes). When I drive my SRT8 through Times Square, I get Europeans taking pictures of me LOL. One time I had a European taking pics of my old V6 2.7L Chrysler 300 with it’s 22″ wheels.

      They TOTALLY ignore the Audi’s and Beemers.

      As for ultraview sunroofs, the sun cooking you is a problem. Fortunately they include shades to keep the sunlight out.

  • avatar
    Volt 230

    What the heck for? I rented a Sonata a few years back with a sunroof, since it was for a kind of longish road trip in hot, sunny, humid Fla Not once did I bother or even think of keeping open the thing, I tried for a minute or 2 and the noise level and wind pressure made me close it again and not bother with it

  • avatar
    gslippy

    I never buy sunroofs because they reduce headroom by 1.5 – 2.0 inches, and I need all I can get.

    I also feel less secure under them (my problem, I suppose), and I’m not interested in paying extra for this potential maintenance headache, anyway.

  • avatar
    carguy

    I like a normal size glass sun roof. They really brighten the interior of most cars – particularly if you have dark trim colors. However, the super sized all glass ceilings that some manufacturers now offer are over the top. Not only do they make the car hot in summer but they also compromise the car’s structural rigidity and roof strength.

    • 0 avatar
      mr_muttonchops

      Ha… over the top. Funny.

      I agree though: a good sunroof is nice. I had a 3rd gen Prelude with a sunroof and absolutely loved it. I didn’t notice any real loss in performance or gas mileage, it made the interior a lot nicer to be in (though it was already tan, so it was bright by default) and with how the car was shaped there wasn’t a lot of wind disturbance.

      • 0 avatar
        Contrarian

        I agree. My latest car doesn’t have a normal size sun roof (my last one did) and I miss it. For certain conditions they are very nice to have. They also vent your car differently than the side windows and can be better to open in the rain if properly designed.

    • 0 avatar
      Detroit-X

      Ditto.

      And for that matter…
      Huge wheels and tires burn you at the pump.
      Huge engines burn you at the pump.
      Lots of options burn you at the pump.
      Carrying lots of junk burn you at the pump.
      Fancy suspensions burn you at the pump.
      Dating fat chicks burn you at the pump.

      • 0 avatar
        golden2husky

        Suspensions??? And you know what they say about fat chicks…they’re like a moped…they can be fun to ride but you don’t want your friends see you doing it.

  • avatar
    mr_muttonchops

    A sunroof that huge just seems a tad much, even in today’s gee-whiz gadget conscious market. However if automakers are concerned about weight, they could always just make the smaller sunroofs out of some kind of plastic like the late Celica did, but it’s hard to say how that would get past safety standards.

  • avatar
    DC Bruce

    AFAIC, a sunroof is not a substitute for a convertible. I have two cars that have ’em, and, after the initial novelty wore off; they never get used. (Also have a roadster.) Apart from the weight penalty, they heat the car interior, which is not a plus if you live south of Canada.

    And, as gslippy says, for those of us who are pretty tall, they usually cut out an inch or more of headroom . . . which could be significant in other than an SUV.

  • avatar
    Mark MacInnis

    Waah, waah, waah. You can have my sunroof when you pry my cold, dead hands off my steering wheel.

    Dammit! Can’t we enjoy ONE thing about driving with the nanny-ninnies, insurance actuaries, greenie-weenies and ruining it for us?

    I LIKE open air motoring. OK, so I won’t have a full convertible, because, well, there is some sense that a rollover crash might be kinda dicey. I get that.

    But I’VE compromised. I’M an adult. I switched from ragtop to sunroof.

    Let me enjoy it without nagging me anymore.

    If it was up to THEM, we’d all be driving uniformly gray egg-shaped hybrids with less than >80 horsepower, 97-airbag, 100 mpg bondage mobiles (you know…”all strapped in and can’t move”) with cell-phone-and-text-zapping technology, with big yellow lights and warning sirens and internet-controlled software overrides to all controls. And zero…by God ZERO! fun.

    Makes me want to beat the [email protected] out of a regulator.

  • avatar
    Russycle

    I can’t see a sunroof making much difference on highway mpg. A couple hundred pounds doesn’t have much effect at steady speeds, and as for turbulence, how many people are doing 70 with the sunroof open? In my cars, it’s usually shut above 40. I run the AC less around town with a sunroof, with windows down and the roof open I rarely need it.

  • avatar
    Wheatridger

    Come on– unlike sunroofs, this article sheds neither heat nor light on its subject. And the headline is sheer sensationalism. There’s no objective, quantified statement here. So a sunroof “adds several more pounds” to a car. In comparison to a 3,000-5,000 pound object, that’s meaningless. It’s the weight of a laptop in a briefcase, or two typical shopping bags, or the jack you carry in the trunk and don’t use.

    Has any sound survey documented a real-world MPG spread in cars with and without sunroofs? We’d like to know. Without that, we’re left to listen to people who don’t own sunroofs explaining why they don’t, and sunroof lovers saying why they do. Please try a little harder next time, B.S. Use your contacts in the industry to inform me, for all the time I give this site, please?

  • avatar
    Sigivald

    Yeah, “several more pounds” is not exactly an indictment.

    I suspect it might even realistically – for a big roof – be 50 or maybe even 100, all told.

    But even that’s not a big deal on that giant 5,000 pound ultra-SUV mentioned – and seriously, who even cares about that marginal-of-the-marginal difference?

    (In fairness, though, note that those are not Mr. Schmitt’s words, but those of a report quoted from at the site linked to.)

  • avatar
    Ryoku75

    Sunroof vs No sunroof really depends on the car itself, some will have identical aerodynamics while others will be different, ditto for the engine.

    A small 1.? engine will hate a big sunroofs weight while a v8 will be in different. Sunroof size itself is a factor too.

    For the record, I’m okay with small sunroofs but just opening the windows is good enough for me.

  • avatar
    el scotto

    Haters gonna hate. Shame on people complaining about something that makes a vehicle more fun. Also, when it is cold out,you can open the cloth slider and let more sunshine, passive heat in. Duh. More there is NO WAY I’ll have one on my Thunderbolt Grease Slapper Gomez Addams Special Edition fanboi shenanigans.

  • avatar
    CarPerson

    Sunroofs are a definite NO! to me. I do not want to pay for one, lose the headroom, mess with the maintenance issues, and wipe the condensation and water leaks off the seats and console.

    17 years ago I had to special order my top model 2-door coupe as the only ones in a four-state area had sunroofs and trunk spoilers. Although optional, every dealer was ordering them installed. When the car came in, my name was at the top of the window sticker as “Built especially for…”. Cool!

    I just tried to price out an Infiniti G37. The base has no available options. The “Journey” has 8-9 option packages. Pick one and all but two of the other option packages light up as REQUIRED. Yes, a sunroof is in the Premium package. You cannot have any safety or security options unless you accept a sunroof shoved down your throat.

    Looking elsewhere for next car…

  • avatar
    lon888

    I’m at a point in my life when I won’t buy a new car without one. I bought a new ’94 Prelude with a sunroof and haven’t bought a car yet without one. Summers here in Oklahoma can reach 115 degrees F. I simply pop up the sunroof and voila instant hot air vent. I don’t have to crack my windows and risk a break-in. Definitely the pluses outweigh the minus’s.

  • avatar
    A is A

    It´s not only the extra weight penalty, it is also the extra fuel you must burn to operate the Air Conditioning unit to cool the hotter interior.

    Give me a honest-to-God steel roof over my head, for Christ sake.

  • avatar
    el scotto

    Are you guys talking about a sunroof where Leon and Duane cut a hole in your roof and permatexed an aluminum ring holding a piece of plastic? Interior condensation from a sunroof? Huh? Hotter interior? Didn’t it have a sun shade built in? What maintenance issues? Clean/lube the tracks a couple of times a year. Leaks? Get a new gasket or use your manual override. Honda used to build in a manual override for their sunroofs.

  • avatar
    Ex Radio Operator

    We got a sunroof on our car because it was an 08 STS leftover after the 09 models came out. Got a very nice discount. I live in south Texas, so yes, I can wear a cowboy hat while driving, if I so choose, and the sunroof doesn’t cause a problem. The cowboy hat is normally in the unoccupied baby seat in the back until I need it. Shut the curtain and you can’t tell the difference between it and a regular top.

  • avatar
    Robert Schwartz

    Hate the things. Most of the time the weather around here is too miserable to be able to use them. They also cut into headroom, and they leak.

  • avatar
    dreadnought

    If it matters, you can add me to the anti-sunroof brigade. Obviously it doesn’t matter though, as so many manufacturers have decided that all their cars must have them, at least in the US. Especially the so-called “luxury” makes.

    I hate that so many of the cars I looked to purchase either had them as standard equipment, or make you get one if you look to buy anything above a complete stripper.

    Leather and xenons are optional (and hard to find ) in a $45,000 Mercedes C-Class, but a sunroof is standard equipment. That is just ridiculous.

  • avatar
    daveainchina

    “If the heavier sunroofs make up more than a third of a vehicle’s production mix, the vehicle’s fuel-economy testing must include the feature.”

    Is this why most lower trims of vehicles don’t even offer them as an option? I know from talking to most of my friends etc they would love a sunroof/moonroof/DLO in the top of the car.

    BUT they don’t want to pay for the top trim model as it generally costs too much and doesn’t really offer anything they feel they need/want, other than the sunroof option.

    Me, most cars baseline trims are enough for me, add in a sunroof and I’d be happy. I sure don’t need nav, and for my commuter vehicle I sure as heck don’t need the big engine. Also, manuals are more common on the bottom trims, soo just add a sunroof and I’d be happy.

  • avatar
    mkirk

    Gotta have the roof man…Otherwise you have to get out of the truck to shoot.

  • avatar
    Wheatridger

    I never thought of sunroofs as such a polarizing issue. The cars I bought usually had them. I used it mostly as a fresh-air exhaust option. Overall, they were nice, but not indispensable. I certainly wouldn’t feel resentful of anyone’s choice not to have one.

    Ah, but that’s the key word, “choice.” When the makers bundle sunroofs with higher trim packages, they take away choices from the consumer. I’m shopping for a Tiguan now, and I’m happy to find that huge pano sunroof available in each of three trims, with and without the navi I don’t want. Actually, I don’t care for any of the car’s high-line features (more chrome, leather, LEDs, jumbo wheels), so I thank VW for giving me the choice of a de-blinged car at a low price, with a sunroof. The other brands should do likewise.

  • avatar

    I have had two cars with sunroofs (a 1996 Acura Integra and a 2002 Mazda Millenia) and really liked them. Never had any maintenance issues although both were driven to extremely high mileage. A while back I rented a Citroen Picasso C4 minivan and was enchanted by its huge windshield, that continues far up into the roof. It was equipped with drawn-down shades and made the C4 feel like a fighter jet in terms of visibility. The Mustang was offered with an extended glass roof/windshield but after strong initial sales two or three years ago, interest has fallen off. This would not have been a sunroof but just a non-movable glass panel. It looks good and probabably makes the interior more spacious-feeling but perhaps the trade-offs (cost, vulnerability, weight) were too much for a performance car. Opel had a similar arrangement in the Astra here in Germany but I don’t see many on the road.

  • avatar
    hubcap

    Bitch, bitch, bitch. Moan, moan, moan.

    And as usual the betas fall in line. Bertel, you should buy a flute. A harmonious melody from your “piece” would send them into ecstasy…or off a cliff.

  • avatar
    Jellodyne

    My 1993 Accord had a nice moonroof. Opened all the way, and when you opened it there was a little spring-loaded wind deflector that popped up so you didn’t get that booming turbulence even if you have all the other windows closed. With all 4 windows down and the sunroof open it was nice and breezy. Loved it.

    My 2000 Accord coupe, on the other hand, because of the rake of the roof the moonroof only opened up like 60% of the way. No flip-up wind deflector. I tried to see if I could source one from the dealer, apparently they stopped making them that way, so if it ever was open all you got was irritating low pressure boominess. And the coupe has no rear windows to open, which would have helped. The dealer did offer a fixed plexiglass wind screen which came up over the first 3 or 4 inches of the moonroof. And like I said the moonroof only opened 4 or 5 inches because of the roof. Plus the coupe has a lower roof anyway, so the headroom is a factor and the moonroof made it worse. Worst moonroof ever.

    My current Fit isn’t offered with any sort of moonrooft, but doesn’t really need it, what with it’s cathedral ceiling.

  • avatar
    epsilonkore

    I have to agree with the article. My daily driver,a 2005 Scion tC, has a dual panel full glass roof. The heavy glass roof is obvious in spirited cornering (and that registers at the pump no doubt) and when both shades are open, and its 90+ degrees out, the air conditioner cant keep pace and runs 100% the whole sunny day, killing economy. It also makes for a super hot interior after being left outside in the sun, straining the A/C from the start. All that being said, I would NEVER give up the all glass roof. I loved it the day I bought the car, and I still do. One way or another I am going to have an option to see the sky be it a glass sun roof or a convertible. Scion just needs to put stronger blowers in their cars that have all glass roofs STANDARD.

    As for leaks and mechanical issues that others complain about, I havent had any (other than an occasional “pop” in the winter over speedbumps from the sunroof) from ANY of my cars with sunroofs. Could be because I grease the mechanicals regularly and use Gummi Pflege Stift ($8 on amazon) on my gaskets once a year. My convertible doesnt leak either… protect your gaskets folks!

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