What's more damaging interior- UV (sun) or heat?

[Viggen]

I've always wondered this.

Say on a hot 90 F sunny day (100%) clear sky summer solstace which is more damaging?

What I personally do is slightly roll down the windows about 1/2 inch so that air can escape the interior but only a bit of direct UV can enter the interior since the remainder of the window (UV blocking) is still protecting most of the inside of the car.

Any experts around here we'd be glad to hear your view on this.

 

[bluestream]

Not sure, but a blanket or towel over the seats saves them from the Sun. Especially leather...

 

[xxch4osxx]

This is why I have my windows tinted 5% on all except the windsheild. When I park, I put up the reflective windsheild guard to protect the interior from the front.

 

[simple_gifts]

I thought I learned years ago that glass blocks a lot of UV radiation.

 

[Hallmark]

Originally Posted By: simple_gifts
I thought I learned years ago that glass blocks a lot of UV radiation.


That is largely correct. However, one of the common misconceptions about UV and the heating of a car's interior is that the heat is created by the infrared spectrum passing through the windows and heating interior objects that it strikes, e.g. dashboard, seat buckles, steering wheel, etc.

To rephrase the isuue in a simplistic manner, UV causes the decomposition of interiors, but infrared causes the heating of interiors.

Of the seven electromagnetic frequencies of the light spectrum, humans only see Visible (V) light, but the other six frequencies, i.e. Radio (R), Microwave (M), Infrared (I), Ultraviolet (U), X-ray (X), and Gamma (G) are all both beneficial and harmful.

 

[Viggen]

@Hallmark:

So would you say that infrared heating (ambient temp) does little or no damage to interior items in the car?

 

[Scorch]

Heat never seems to be an issue in any vehicle since the interior plastic is only going to seat better from it... that's my feeling anyway. No issues from heat on 8 year old plastic, I don't like to crack the windows because loads of dust/pollen gets inside and all over everything.

For protection, 303 Aerospace cannot be beat for the dash, doors, console and any other plastic in the interior.

I don't use a sunshade, inconvenient and silly to me, but I live in a state where the sun isn't near as powerful as say Florida.

 

[RoGuE]

Sunshades are a necessity in the south and southeast. The interior temp is easily cut by 30 or more degrees I think by putting it up on the hottest days.

 

[tonycarguy]

Glass (either automotive or household) only blocks UVB radiation. It lets most UVA pass through. The exception is the front windshield which has a coating that blocks most UVA and UVB, and aftermarket tint which blocks 99% of all UV. You can get 75-80% window tint (which is legal in most states even on front windows) that blocks 99%+ of UV. It will protect your skin and the car's interior.

UVB is what causes sunburns. UVA causes skin cancer.

 

[tonycarguy]

Originally Posted By: Viggen
@Hallmark:

So would you say that infrared heating (ambient temp) does little or no damage to interior items in the car?


Heat definitely harms your car's interior. The heating/cooling cycle causes plastic and leather to deteriorate. Some objects like cloth seats aren't affected much by heat but more affected by UV. So the answer is to protect the car from both UV and heat.

 

[lexus114]

Originally Posted By: Scorch
Heat never seems to be an issue in any vehicle since the interior plastic is only going to seat better from it... that's my feeling anyway. No issues from heat on 8 year old plastic, I don't like to crack the windows because loads of dust/pollen gets inside and all over everything.

For protection, 303 Aerospace cannot be beat for the dash, doors, console and any other plastic in the interior.

I don't use a sunshade, inconvenient and silly to me, but I live in a state where the sun isn't near as powerful as say Florida.



Uhhh, I dont think so! Good example of this is the early 90`s Pontiac Sunbird dash`s. Also,I absolutely recommend using a sun shade. It takes less than 60 seconds to put up,and really help`s to save the interior.

 

[bigmike]

I've tinted the windows on every vehicle I've owned, use a sunshade even in winter or on cloudy days, and park facing away from the sun (or North, if parking all day). I crack the windows if I have vent visors installed. Never had a plastic or interior problem to date.

 

[Bamaro]

UV is worse

 

[CROWNVIC4LIFE]

Originally Posted By: bigmike
I've tinted the windows on every vehicle I've owned, use a sunshade even in winter or on cloudy days, and park facing away from the sun (or North, if parking all day). I crack the windows if I have vent visors installed. Never had a plastic or interior problem to date.


That is exactly what I do..I have vent visors but do not crack the windows anymore cause the landscrapers always seem to come by everwhere I go blowing dirt into it..No plastic or interior issues from the sun or heat.

 

[morris]

o-zone.

 

[Hallmark]

Originally Posted By: Viggen
@Hallmark:

So would you say that infrared heating (ambient temp) does little or no damage to interior items in the car?


I was away...wasn't ignoring your inquiry.

The answer must have an asterisk. As long as interior temps remain 'reasonable' (defined as less than 130F by automotive testing standards), damage is unlikely to any interior object. However, vehicle/aviation interiors of 160F+ have been documented and can cause molecular alterations in some petrochemical (plastic) materials.

Interior heat increases occur when nonIR frequencies pass thru the windows, strike an object, and are converted to IR frequencies. Block the light and both destructive UV AND IR heating potential will be reduced/eliminated.

 

[Rick in PA]

UV can be pretty rough on plastics. For example; nylon wire ties. I've seen natural (off white) nylon wire ties that were exposed to sunlight, embrittle over time and fail. They make UV resistant wire ties, I think by compounding in carbon black. It keeps the UV from penetrating the nylon. Plus, we've all seen yellowing of surfaces and fading of colors due to the UV in sunlight. That UV is potent stuff.

 

[SkyGod]

UV is worse than heat.
Garaged cars suffer from nearly the same heat as vehicles parked outside,but you can easily see the difference in cars parked outdoors.
cars parked outdoors most likely fade quickly unless waxed often.
I try to park in shady spots..but keep away from trees.
Birds are nearly as bad on paint as Uv or heat.
I use vaseline on my interior plastics..never use protectants.

 

[rslifkin]

^ I've done the vaseline thing too, and it works pretty well.

 

[lexus114]

Originally Posted By: Rick in PA
UV can be pretty rough on plastics. For example; nylon wire ties. I've seen natural (off white) nylon wire ties that were exposed to sunlight, embrittle over time and fail. They make UV resistant wire ties, I think by compounding in carbon black. It keeps the UV from penetrating the nylon. Plus, we've all seen yellowing of surfaces and fading of colors due to the UV in sunlight. That UV is potent stuff.



And it`s getting stronger!