Should I Get My Car Windows Tinted | The Top 10 Tips | Auto Expert John Cadogan

https://www.youtube.com/watch?v=mMB2v-bsaRI

Transcript

00:00
Time for a quick Jihad on bullshit: the top 10 things you need to know about window tinting.
00:08
Good idea or not? That’s next. Warning: This segment is rated ‘S’ for
00:20
‘science’ and ‘T’ for ‘thermodynamics’. I’m very sorry about that. Occupational hazard.
00:26
I’m John Cadogan from AutoExpert.com.au – the place where Aussie new car buyers save
00:31
thousands off their next new cars. Without face-to-face car salesman brain damage … unless
00:39
of course you really want that. We could arrange it, hypothetically. It’s just nobody’s ever
00:44
asked for that specifically. Hit me up on the website if you want a new car cheap. In
00:50
‘Straya. That’s what I do. Lots of people ask me about window tinting
00:55
– last week, I got this: “Is aftermarket tinting of any value? Our
01:00
whole family is fair skinned. I believe the standard side windows are by default SPF 46
01:08
or 48 and custom darkest legal tint only improves that to SPF 50. Are these figures correct
01:15
and if so what is the value of this accessory?” So – for those of you unfamiliar with ‘Straya:
01:21
We love football, meat pies, kangaroos and … melanoma, sadly. And that last one is
01:28
a real problem, driving along mid-summer in our sunburned country in our shiny new … ultraviolet
01:35
ovens. There are actually three flavours of UV light.
01:45
UVC, which never really makes it to the Earth’s surface – so, not really a factor. UVB, which
01:51
is what causes sunburn – but is not that prolific. And UVA – the big one – 30 to 50 times more
01:59
prevalent than UVB. Penetrates the skin more deeply. And then has prison shower sex with
02:06
your DNA, unpredictably. UVA is what you bombard yourself with if you’re
02:13
moronic enough to lie in a solarium. There’s no case to be prosecuted that exposure
02:20
to any of the flavours of UV is a good idea. Especially if by ‘you’ it means you parking
02:28
your caucasian/Celtic DNA in our sunburned shithole this summer.
02:40
While we’re talking flavours: There are two flavours of automotive glass – laminated and
02:46
tempered. Laminated glass is used for windscreens. Where glass is the bread, and a layer of polycarbonate
02:54
is the filling. Happily enough, laminated glass blocks almost all UVA and UVB radiation.
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The second flavour: Tempered glass – like the windows and the rear screen on most cars.
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It’s just normal glass that’s been heat treated. That toughens it up and introduces
03:12
high residual internal stresses so that when it breaks it does not form long shards that
03:19
slice and dice you in a crash. That’s bad… Sadly, tempered glass really only blocks almost
03:26
all UVB radiation (the sunburn one). Unfortunately, tempered glass blocks only about 20 per cent
03:34
of DNA-damaging UVA (that’s the prolific one). In other words – it allows 80 per cent of
03:40
UVAmore or less straight through. And that’s just a rough guide – the actual
03:46
amount transmitted depends on the composition of the glass and the thickness – it’s not
03:51
like there’s a mandatory standard for UV transmission and automotive glass.
03:57
So – you’re definitely better off driving with the air conditioning on, and the windows
04:02
up. But if you are driving along and the sun is streaming through the side glass, you probably
04:08
won’t get sunburn but you are still being bombarded with about 80 per cent of ambient
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UVA. So that’s hardly ideal. Does it not therefore suck the big one that
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most sunroofs are tempered glass, and not laminated? I mean, if the world were perfect,
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I’d take laminated, and banish both UVA and UVB. Unfortunately, that’s not a choice
04:42
available to even the scientifically literate contemporary new car buyer. And I hate that.
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Credible branded tint films – from a business you could conceivably believe, like (say)
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3M – make claims about UV protection. 3M says each of three of its automotive tint films
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(quote) “blocks up to 99 per cent of harmful UV rays” and for the other one it’s “up
05:14
to 99.9 per cent”. So that sounds pretty good.
05:18
Unfortunately though, I don’t know what “up to 99 per cent” actually means. Last
05:23
time I looked, it meant “less than or equal to 99 per cent” – which is hardly reassuring.
05:29
I don’t know what “harmful UV rays” are, either. Because, according to the Cancer
05:34
Council, they’re all harmful. I don’t know if this 3M “up to 99-whatever”
05:40
business is just lawyers and their weasel-word bullshit, and/or generalised marketing department
05:46
arse-covering and/or illiteracy. But it hardly inspires complete confidence in the product.
05:52
If you were to take these 3M claims in the most favourable inferential light possible,
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there is absolutely a case for window tinting if it could be guaranteed as a means of blocking
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all of that UVA that the side glass is so absolutely good at letting through to ravage
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your DNA. According to the Cancer Council:
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“Clear or tinted films can reduce the amount of UV radiation penetrating through the side
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glass by over 99%” According to 3M, one of its four automotive
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tint films are (quote): “SPF of over 1000” but two are only (quote): “SPF of up to
06:37
1000” – damn those legal and/or marketing bullshitters to the pit of hell. And the remaining
06:44
one enjoys no SPF designation on 3M’s website. 3M also says those three products that do
06:52
enjoy SPF claims are Skin Cancer Foundation recommended products.
07:02
The scientifically illiterate are pretty good at conflating visible light, heat and UV – but
07:10
they’re actually from different parts of the spectrum. So it’s worth noting that
07:15
even a film that looks ostensibly clear – like the 3M Crystalline one – can allow 90 per
07:22
cent transmission of visible light and still do the mad “up to 99.9 per cent” UV-blocking
07:29
voodoo. It’s also worth noting that while dark films
07:33
are perhaps a bonus in the daytime, they might be a safety compromise at night. Which is
07:39
why there are regulations. Here in ‘Straya, there are only regulations
07:50
for visible light on window tint films, not UV. It’s called ‘Visible Light Transmission’
07:57
or VLT. The minimum VLT is 35 per cent. In other words, tint films are not allowed to
08:04
block more than 65 per cent of the visible light.
08:08
No tinting is allowed on windscreens – not even a clear film – except in a strip up the
08:15
top. In the Northern Territory 16 per cent VLT is allowed on windows behind the driver
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(so – second seating row and back from there). In WA and Queensland it’s 20 per cent.
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If you breach the VLT specs in your state, and get pinged, the car is rendered unroadworthy,
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and then – in the immortal words of Gunnery Sergeant Hartman – you’ll be in a world
08:42
of shit. I really don’t think there’s that much
08:50
of a safety component to tinting. Dark films might reduce side vision a little bit at night,
08:57
but might also reduce fatigue during the day. In a crash where the side or rear glass gets
09:03
shattered it might mean there’s fewer hail-sized residual stress relieved glass particles being
09:10
shot around inside thanks to inertia. The film might bind them together. Just like The
09:15
Force. Right about now we’re on the cusp of another
09:23
six months of summery hell, here in ‘Straya. So a key question among car buyers is: Will
09:31
tinting make my car any cooler? And the clear answer is: Not really. Tint
09:38
film manufacturers – knock me down with a feather – make all manner of bullshit claims
09:44
about cooling. Here’s one 3M prepared earlier. “…rejects up to 97% of the sun’s IR rays
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and rejects up to 60% of the heat coming through your windows.” – 3M
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This is one of those bullshit claims that’s probably true – it’s just self-promoting
10:02
and meaningless. Inconsequential is probably the best word for it. There are two main modes
10:09
of heat transfer to and from your car – radiation and convection.
10:16
Radiation is from the sun streaming through the vacuum of space – those photons – for
10:22
500 seconds, or something, and then belting into your car and turning it into an oven.
10:28
And convection is the main mechanism for heat loss from or cooling from the hot car – essentially
10:33
bleeding heat off into the surrounding air. That’s just how this works. Heat transfer
10:40
for dummies. Eventually you get to a point of temperature stabilization – you might call
10:46
it heat soaking, where heat loss to convection equals heat load from radiation. (And I’m
10:52
simplifying this just a bit, because the car also rejects heat by radiating.) Anyway – the
10:58
thermometer is stable, ultimately, in respect of the air temperature inside the car. Thought
11:05
experiment time. Summer. Hottest part of the day. The main
11:09
radiant heat load is hitting the roof, not the windows. Therefore, the windows are not
11:15
a contributing factor in a major way to radiant heat load. They’re just not. Therefore,
11:22
tinting can’t help much, even if it does block radiant heat. Tinting is also an additional
11:28
layer of thermal insulation over the windows – and this will hinder convective heat loss.
11:35
Marketers – such bullshitters – the up until now undiscovered fourth law of thermodynamics.
11:42
If tinting actually made your car cooler, 3M and its competitors would be doing umpteen
11:49
tests that demonstrate this everywhere from here to Dubai and Egypt.
11:55
If you want your car to be cooler in summer – just park under a tree. The leaves absorb
12:00
solar radiation to photosynthesize. Or fit a small adhesive solar panel and run a fan
12:07
that draws ambient air into the car to improve convective heat loss from within. Far more
12:13
effective If you decide to go ahead with getting your
12:20
car tinted you want someone credible doing the job of applying the film. Make sure they
12:26
give you a guarantee, and make sure they’re likely to be in business still, in three to
12:32
five years – in case you need to make a warranty claim. Make sure they don’t exceed the VLT
12:38
limitations in your state. Make sure they use a credible film from a
12:43
reputable manufacturer – not some cheap Chinese knock-off crap that looks suitably dark but
12:49
which you have no way of knowing whether or not it actually blocks any UV radiation. That’s
12:56
kind of important. Commercially, one of the ways a tinter can
13:00
pump up his profit is using the lowest cost tint film. The input materials, right? You
13:08
definitely don’t want that. Finally, my number one tip is: Do not get
13:18
the dealership to tint the windows for you. They get the same tint guy you could get to
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do the job. He’ll drive in, in his van and he’ll do it before you collect the car.
13:30
It’ll be a convenient exercise. It’s the same tint, done by the same guy
13:36
– guaranteed. The only difference is: The dealership will screw him down on the price,
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and mark up that same price up for you – by the traditional dealership parts and accessories
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margin of one billion per cent. On special – this month only (perhaps): We’ve
13:55
slashed our margin on tinting down to just 500 million per cent. That’s 50 per cent off.
14:00
Don’t miss out. (That statement brought to you by honestadvertising.com.)
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The dealership will of course dangle the carrot of wrapping this over-the-top tinting cost
14:12
in the finance – so you can generate even higher commissions for the dealership there,
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and pay even more, ultimately, for the tinting. Lucky you.
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In conclusion:Automotive glass does a decent – but not exemplary – job of blocking some
14:33
UV. Unfortunately it does allow quite a lot of damaging UVA straight through. Tinting
14:40
– with the right film – is certainly a hedge against that. The dark stuff for the rear
14:45
glass – in the states that allow that – is a decent (but imperfect) hedge against prying
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eyes, too. And it could help in a very minor way in a crash.
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But blocking that UVA is the main rational reason for getting your windows tinted. Up
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to you. I’m John Cadogan – thanks for watching.
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