will having a solar sunroof affect mpg?

welcome! i suppose a little because it's not as smooth for air flow, but probably not a lot.

 

I don't think you'll be able to measure the difference outside a lab, and I presume that's where you'll be doing most of your driving.
Personally?
I don't think it's worth the extra $$$, and I live in the deep South, but I don't think you'll notice an MPG ding.

YMMV

 

there has been some discussion, but I have not seen any hard facts http://priuschat.com/forums/gen-iii...olar-roof-changes-roof-line-aerodynamics.html

The Prius MPG is rated the same with or without. I bought my Prius for the power sunroof, not for the solar panel. But they come as a package. Keep in mind that the solar panel and sun roof are not linked in operation.

 

One big benefit of the solar roof is the interior is closer to ambient outside temperatures. While this is more comfortable for occupants entering the car the really cool benefit that most people don't think about is the fact that your AC doesn't have to work as hard to cool down the car and it can do it faster than the same car without the solar roof. The Prius can take a pretty big MPG hit when the AC is first turned on if the inside car temperature is much higher than the desired temperature.

i.e. If you jump in a non-solar roof equipped Prius and it is 130degrees inside you are likely to crank up the AC to cool the interior down. So you set the AC at 70degrees and the compressor will run at full speed to try and reduce the interior temperature. During the first 5-30min you may observe a 2-10mpg drop in MPG. There are a lot of factors that determine the actual observed MPG loss but it is guaranteed you will lose MPG until the interior is cooled off and the compressor can "relax".

I have done quite a bit of testing on the MPG impact due to AC use on the GenII and I have observed a VERY consistent 10mpg drop when the AC is used to cool down the interior during really hot days. Once the interior is cooled down close to your set temperature the loss is reduced to only 1-2mpg. Unfortunately on really hot days it could take over 30 miles to get the interior cooled down. During two tests last summer I drove over 30miles (@ 65mph) before the interior cooled down enough for the MPG loss to go from 10mpg to 2mpg).

I would love for someone with a GenIII to conduct similar tests in as a controlled manner as possible. I have a feeling the impact will be less but still quite large.

Watch my quick video to better understand what i am talking about. If you are not familiar with the ScangaugeII the MPG indicator is located in the lower left corner of the gauge.

Then read my thread on how to reduce the MPG hit from AC use.

http://priuschat.com/forums/gen-ii-prius-fuel-economy/97814-how-reduce-mpg-loss-because-c-use.html

So be happy you have the solar roof. It was very expensive but it's more than just a cool looking roof ornament. lol

 

I love it for these very same reasons. I think it was worth every cent. Nothing like getting into a car on a 95F day & the car isn't 140F inside. I also enjoy the sunroof open on nice days.

 

Apparently the Solar roof adds weight, which will affect mpg slightly. Here in the UK, the Solar roof version (only available on the T-Spirit) comes with the smaller 15" wheels which brings the mpg and emissions back down to the same as the non solar roof versions with 17" wheels.
BTW. I've never understood how smaller wheels with the same rolling radius (OD) give more mpg.

 

I've got a gen3 Prius with solar roof. I've heard that weight is increased of about 20 kg, and I would say that car handling get a little worse because the extra weight is located at the top of the car. More you have a penalty for a little worse aerodynamic at high speed. That said, solar roof is good for the reasons indicated above by F8L (less AC use) and kithmo (195/65 15" wheels instead of 215/45 17", I guess: 15" wheels are required with solar roof to reduce vibrations to the soar panel).
As you can see by my avg, the overall fuel economy with solar roof can be fine anyway.
Best regards

 

Before we bought our Prius I was worried about the weight from the roof, leather, nav, etc. affecting mpg. Even though the weight increase does affect fuel economy to some extent I am happy we got the features we wanted because it makes the driving experience more enjoyable to me. Driving technique can impact fuel economy much more than a little extra weight in a car. And why not get the features you want in a car if you can afford them?

10,000 miles and 52.2 mpg later I never think about any lost fuel economy.

 

what facts are you basing this on? It is like saying one guy that weights 20kg more than the next will never get the same MPG. Stating it adds weight is fine, but I have not seen any data to translate that into actual losses of any type (aero, mpg, etc). I am waiting to see facts actually since I have a solar roof. I think it is insignificant, but that is my opinion.

 

get the civic! they're way better than prius by any estimation.eep:

 

I would love for someone with a GenIII to conduct similar tests in as a controlled manner as possible. I have a feeling the impact will be less but still quite large.

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Not a contolled test but with temps approaching 40degrees C, I have used the A/C a lot and my most recent two tanks showed an average of 4.9l/100ks as opposed to my usual average of 4.8.

 

So... is this thread saying that with the Solar package I should stick with the OEM 15's? Are there any OEM 16's out there? I will do some searching here in the forum for the difference on the MPG vs Wheel size and specific tires. I will be getting these 5 star split spoke 15's (which I don't like as much).

 

Many owners with the solar sunroof have 17" or 18" wheels without issues.

 

My neighbor across the street has hybrid civic.

She tells me that when the A/C is on and she is at a stop light, the A/C will shut off.

Not sure if this is an option or a standard feature to increase mpg.

With this knowledge, I made sure to check out what the Prius did during a test drive.

Good to know that with the A/C on at a stoplight, the A/C will continue to cool the car.

This was a deal breaker for me.

Just a thought....

BTW I have the sun roof/solar panel pkg. I love the fact that with my tinted window and sunshade in the front windshield the interior of the car is quite comfy to enter on a hot summer day.

I took was looking at only a sun roof, but was only available as a pkg with the solar panel. Glad I got it!

 

There's no way in hell I'd buy a Honda hybrid. They seem to have serious issues w/hybrid battery longevity. I've seen numerous people on Hybrid Cars - GreenHybrid - Hybrid Cars who've needed HV battery replacement on Honda hybrids well before 150K miles. A friend of mine from college had hers replaced under warranty on her HCH last year (I don't remember the model year, but it was one where they still offered stick).

See http://priuschat.com/forums/gen-ii-...071-salvage-traction-battery.html#post1252078.