Solar Roof - Does it work?

[bearpaw]

Greetings - I would love feedback on whether the solar roof cooling system really works. Does it efficiently lower the interior temperature? Is it true that it will only work in direct sunlight or can you park under the shade of a tree and still have it function. Finally, how well does the system work in humid climates? If you have temperature readings, especially those of you in humid climates, could you post them? Thanks.

BTW - an earlier post (below) suggested that you had to crack the windows to boost the efficiency...! The other tips in the list make perfect sense, but I live in an area that receives frequent rain showers so leaving the windows opened is simply not an option.


"1. GET A HEATSHIELD!
2. Crack all the windows about an inch or so.
3. Use the SR in conjunction with the remote a/c, which is how it is designed to be used.
4. Ambient means "close" and that's exactly what happens. Don't expect the same int/ext temp. It's not going to happen."

[HTMLSpinnr]

Your #1, #3 and #4 are dead on. In Phoenix, it will still be 10-15˚F higher inside than out *WITH* a HeatShield. Still FAR better than w/o the ventilation.

I disagree w/ #2 (the efficiency of cracking a window). You permit more dust, rain, theft, etc., and you "encourage" the air to escape early, limiting "cooling" toward the rear of the vehicle.

You're not going to get much love in the shade (solar gain is less there though), and overcast skies will reduce the power to the blower. Early or late in the day you'll hear "groaning" as the brushless motor attempts to start w/ insufficient voltage.

[DaveinOlyWA]

i found the solar panel will work in ambient light without direct sun, but not very well. i sat in car about 2 months ago and checked its progress. was about 9.30 PM and had, at best filtered setting sunlight thru trees.

fan on, med low speed (guessing by sound) ran 15 seconds shut off. for about 30-45 seconds, then came back on again. and that is about how it ran.

for comparison. at 2 pm in nearly fun sun, fan would run (granted nowhere near as comfortable so did not check this much) nearly all the time and at probably medium to one notch past half way speed. it did shutdown once but then started back up again after about 10 seconds. after watching it run about 7-8 minutes, i gave up on trying to decide how long it would run again before stopping

[RickFlashman]

That's why I simply ordered the Japanese market OEM window rain guards... so I can do my "own" solar roof... leave windows open a crack, heat shield in front window. A lot cheaper.

[yuving]

My solor roof does power up the fan, but I dont think it "efficiently" lower the temperture in the interior. I live in CA, so the fan helps a little, but the interior is always hotter than the outside.
I find open the moon roof a little does help the hot air escape from the top.

[snoctor]

The solar panel does work. I've been comparing temperature readings with solar vent on and off, and with or without a windshield heat shield. I can't open my windows because of dust. When it is very hot and sunny (~100F) the car interior will be about 125 with vent running. Without the solar vent the temp will be over 150F. When the outside temp is ~90 the car interior will be around 105 - 110 (these measurements taken in full sun). In cooler temps the vent is even more effective because it sucks in the cool air from outside and the car interior temp will be closer to "ambient" I've been taking readings without using the remote AC unit because I was interested to see how much difference the solar vent makes. It is actually comfortable when you get in the car and I'd rather use the power stored in the battery to drive the car rather than cool the car down. I've found that just using the solar vent, the car is cool within a couple of minutes of driving. I believe using the remote AC is unnecessary (unless you are entering the car with an infant, etc, or just plain love AC). Finally, in full sun the vent is blasting at high continuously, as somebody noted above. I'm going to edit my first entry in the thread "Solar Roof Temperature Report" so it includes all the data from mulitple temperature readings... that way people don't have to wade through multiple pages to get answers.

[TKY]

Bearpaw, I have a Prius IV with Solar Roof; here are my thoughts:

"solar roof cooling system really works." This is a ventilation system, not a cooling system.
"Does it efficiently lower the interior temperature?" If by "efficiently" you mean without draining the cars power, the answer is yes. It efficiently keeps the temperature from rising in the car as high as naturally would without the solar roof. It DOES NOT lower the interior temperature. It circulates the existing air with a ventilation fan to prevent the temperature from rising in the 130 - 150 degree range.

"Is it true that it will only work in direct sunlight or can you park under the shade of a tree and still have it function." My understanding is that this is correct. The solar power collected and converted by the roof panel does not store any energy, it uses the energy it creats to drive the ventilation fan; that's all.

"Finally, how well does the system work in humid climates?" I live in Denver, Colorado. I'm at 5200 feet with very little humidity.

"If you have temperature readings, especially those of you in humid climates, could you post them?" When it is 85 degrees, or so, outside my cabin has been about 105 to 110 degrees. That in direct sunlight at one mile in altitude where the effects of the sun are significantly different then the heat effects of the sun at sea level. My car is noticeably cooler than my previous car when parked outside, even with the windows cracked.


"1. GET A HEATSHIELD! - Definitely
2. Crack all the windows about an inch or so. I can't speak to this, I do not crack my windows and I have appreciated that my car is not broiling hot and I can touch the steering wheel without burning my hands.
3. Use the SR in conjunction with the remote a/c, which is how it is designed to be used. The remote A/C has a limited range and time duration. It won't run the battery so low you can't start the car.
4. Ambient means "close" and that's exactly what happens. Don't expect the same int/ext temp. It's not going to happen." I agree.

Regards, --TK

[RickFlashman]

Originally Posted by RickFlashman

That's why I simply ordered the Japanese market OEM window rain guards... so I can do my "own" solar roof... leave windows open a crack, heat shield in front window. A lot cheaper.

I got a private asking about this, Sigma has them under "Window Visor":

Toyota Prius 2010+ ZVW30 Exterior Accessories :: Sigma Automotive

[32kcolors]

I've heard SR owners say they got SR so they don't have to look for a shade to park under, but they're more likely to end up with faded paint.

[AF-Vette]

The Solar Roof (SR) is a great option that really works! It keeps the interior close to ambient temperatures without allowing dust and bugs in. Using a windshield sun shade will also help, but when the the SR is working, the A/C will not have to work as hard cooling the car interior down - it it already cooler than an oven, so you will feel cooler, sooner. I hate cracking the windows since that is an open invitation to thieves.