Does window tinting helps to reduce heat in the car?

Ahhhhhhh! This is a no brainer, YES!

 

With the same effort it took to type and post your question on this forum, you could have searched it on Google.

 

I will say this, once you start the A/C, a car that is tinted to the legal limit of your province should cool much faster than a car with factory tint. (I am 2200 km southwest of you, Tint may have less effect for you)

http://www.iwfa.com/Portals/0/PDFDocs/Law_Charts/Canada Window tinting Law Chart.pdf
I doubt you can further tint the windshield or front side windows legally. Any tint is legal behind that, so park so the sun hits your car from behind.

 

Depends also on the material and quality of the tinting material applied.

SCH-I535

 

I posted a similar question in a Honda fit forum and got responses confirming what xliderider says: the type of material and quality are as important as how dark you go. Those who sell their tinting prowess will not necessarily tell the truth, the whole truth, and nothing but the truth. I personally don't like the way tinting looks, but if it will help keep the inside of the car from falling apart due to hot summers, I may have to pull the trigger - at least on the Fit.

 

Yes.

Do sunglasses help shade the sun from one's eyes?

 

I have Formula One ceramic tint. Good heat rejection, supposedly does not interfere with RF signals like BT, radio, and satellite reception unlike metallic films. Lifetime, nationwide warranty. Premium priced though.

SCH-I535

 

I park facing the sun, and put a nice reflective shield. That, and keeping all four windows cracked open helps a lot. Oh, and I am happy to walk for shade

 

That is not a good analogy because in the case of the car, some of the heat rejected by the tint is captured as heat by the glass and then conducts into the cabin.

 

The question implies that heat exists in the car and the tint is supposed to help lower the inside temperature. Therefore, the answer is No.

 

This is a very complicated question, as there are various conditions you can put the car in.
1. Parked in the shade. Tint has no effect
2. Parked in the sun with all windows closed. There should be some benefit from a quality tint, but not much. The car still will be hot inside.
3. Parked in the sun with windows cracked a little ( or , even better, with solar roof running ventilation) - this is when you will feel the benefits of the tint
4. Driving the car in the sunny weather with ac on and windows closed. Tint will make a noticeable cooler interior in this case, and ac will work less hard to keep it cool.

Thanks,
- Alex

 

Nano tint by 3M works wonders. It cost me a fortune to tint my Civic hybrid (around $580 or so including windshield) but I could park it in the sun and come back 5 hours later and the water bottle I left in there would still be room temperature. I am thinking about doing this to my Prius, too. I definitely got better mpgs because of the lower a/c load, too.

 

I was quoted $700 + $300 for the windshield for $1000 total. That's about twice the estimated higher range I'd conjured in my head based on internet hearsay.
(3M Crystalline, CR70 fronts, 50 rest.)

 

Holy batman. I paid half that for my Crystalline tint. I did 40% all around and 70% on the windshield. It is worth the price I paid, but not $1000. That is ridiculous.

 

Think of tinting as a shade. Will putting your car under a shade reduce heat? Yes.

 

Shop #2 quoted $650 + $250 for $900 total. That's the licensed 3M-site referred installers nearby. Not sure if I just suck at shopping for this kind of work but someone on a bimmer webboard said he got $700 total.

Yes, I'd been reading $500 was toward the higher end for whole car tint jobs, so I was mentally preparing to pay around that for the 3M crystalline. My mind is currently still reeling.


To address the question of the OP, tinting should reduce heat within the cabin of the car compared to no tinting except in cases that have been pathologically intended to actually increase heat in the cabin.

The question one is actually interested in is: Will the difference from the added tint increase the personal comfort of the occupants based on perception of heat? Like with a home, discomfort actually has 2 main components: humidity and temperature. Tint only affects the latter. I find it's better to think of heat flow instead of temperature. Heat flow into the cabin can itself occur by 2 means: radiation and convection. Tint film addresses the former (primarily).

I've discovered a couple problems with tint demos during their sales pitches.

1. The heat lamp demo trick
   
   This involves a demonstration where a tinted sample pane is shown to block the heat from a heat lamp, perhaps mounted in a box or just held behind the pane, while the customer can hold their hand to feel the difference in heat blocking.
   
   The problem with this is that heat lamp bulbs output a particularly narrow IR frequency range. If the sample film conveniently happens to block out just that same range, the demo will feel cooler while the real life objective of blocking direct blazing summer sunlight may be unaddressed.
   
   
2. Tint film specs not mentioning what they reflect vs. what they absorb.
   
   I've read reports of windshields fracturing, apparently due to thermal expansion because of poor film. My guess as to the explanation for what happens is that the film doesn't reflect the primary heat-carrying radiation, but absorbs the heat into itself, which then convects back into the windshield.

The first problem requires some deeper analysis. The desired objects are to see through the tint easily while blocking all "heat" and damaging UV, yet without blocking cell signal. Resorting to physics and being thorough, that means we want to:

• PASS Radio Waves: (AM/FM/cellphone frequencies: 850,900,1900MHz)
• PASS Microwaves: 1mm - ... (wifi, 802.11abcgn: 2.4GHz, 5Ghz)
• BLOCK Far IR: ~8µm - ~1mm (thermal IR, human body temps)
• BLOCK Mid IR: ~2.5µm - ~8µm (solar heat from hot days)
• BLOCK Near IR: ~750 - ~2.5µm (really hot temperatures)
• PASS Visible light: ~380 - ~740nm (want to see the road, baby carriages, old ladies)
• BLOCK UVA, UVB, and UVC: < ~380nm (skin cancer, dashboard cracking from UV damage, etc.)

"Heat" infrared spans the entire IR range, even though it seems "peaks" occur in specific ranges. Films that only block NIR or subsets of NIR would mostly be blocking IR from temperatures we would rarely see. This suggests it's most useful to block IR ranges corresponding to hot summer temperatures (80F - a few hundred F) which would be more the mid and far IR ranges and not (just) near IR.

As for the #2 problem, I've not found a manufacturer's film where their IRR (infrared rejection) ratings distinguish between whether it reflects or absorbs it. Suffice it to say though, stated solar rejection isn't really standardized. The more useful test would be an empirical experiment with say boxes made of auto glass tinted with each film and temperature sensors inside the box area.

 

My understanding of the Physics of tint is limited, but it follows the general rules of heat transfer: conduction, radiation, and convection.

Since the tint is placed on the inside of the glass, some of the infra-red (IR) and visible (V) pass through the tint, some is reflected, and some (?most) is caught up in the glass. This latter amount is in turn partly radiated outward as IR, and I think most is conducted and or convected to the cabin and outside air.

None of the above really helps with shopping though. For that look at solar heat gain (SHG) or its inverse, glare, and amount of Visible light transmitted. And while tint is a very good thing (TM), it really is helped by using a sunshield facing the sun, cracking the windows for ventilation, and walking for shade.

 

For convection and conduction, I'm thinking heat insulation under the trim against the body panels.