How much for Tint ?

Nothing to do with IR or UV rejection, a lot to do with heat rejection. Heat comes with any part of the spectrum, once it hits a dark surface and is emitted as IR inside the cabin.

 

I'm getting my prius tinted today 20% sides and back; strip on top of windshield. $180
Here's a question for y'all. Did you do additional tint to the bottom half window on the back (that's already slightly tinted)?

 

Fair enough.

 

And to be a bit more accurate, that is only talking about IR that we perceive as 'heat.' Radiation of any wavelength has an energy that is transferred (to varying degrees) to any surface it hits. In a sense we are like the proverbial frog in (hot) water when we are irradiated by visible light: we are relatively comfortable, all the while the temperature is rising

 

I am getting lost in the words(science logic), do tints help reduce the heat in the cabin or it is making the car look good with no real effect on the
temp inside the car.

 

yes

 

So, Chrisj428 you are saying that if I tint my windows to stop the sun radiation in the summer it will still let it in during the winter????
Doesn't make sense to this old truck driver!

 

Ceramic tint Llumar FormulaOne - i did 11 windows for $310. front driver/passenger @35% tint and all the rears at 30%. the front windshield was another $150 for that and i didn't want to spend $500 on tinting. This picture was taken last month in the high desert in Mojave, California. it was around 9:00 and still in the 90's. The desert heat is hot in the summer (no kidding) ask anyone from Phoenix, so ceramic does the best job at IR rejection without going super dark. The picture is deceiving but the tint looks pretty close to factory. The optical quality is nearly perfect and the tint is guaranteed for a lifetime and is transferable.
The person above that posted - the ceramic cuts out most of the heat in the cabin, ditto for the winter. Dyed plastic tint, the type you pay under $200 doesn't cut out as much, but the darker you go the more heat it rejects and the more light it blocks. 15% tint lets in 15% of the light... what i don't like about the dyed tints is the color of the film. they are either blueish tint as in Medico (which was my second choice) they do this on the front windshield at 80% if you tint the front.

3m Pinnacle i believe was a grayish bronze and other tints are green grey or some flavor of bronze, grey, gold, green, etc....

if you every look at a Tesla that has been tinted, they usually spend the money on a ceramic tint, and it makes the car cooler in the cabin by a huge margin over no tint. it was a tad expensive for a prius, but i shopped around and saved $140. So instead of $450+ i got the 11 windows tinted for $310. I really like the tint... it was the best upgrade to the car.

 

No, that's not what I'm saying.

You said:

I said:

What that means is this: The amount of gas you'll spent cooling the car without tint is more than the amount of gas you'll spend heating a car with tint. So, if you're looking at it from a strictly economical standpoint, tinting the vehicle appears to have a greater cost-savings vs. leaving the vehicle untinted. However, if you never use your A/C in the summer, then that's a different story.

 

Winter cabin heating is mostly from engine waste heat in a Prius, so the limited view of whether tint saves pocket money is entirely a question of summer AC savings.

AC has a COP of ~ 3, and uses petrol that say costs $3.34 a gallon that contains 33.4 kWh and is combusted at ~ 33% efficiency.
Very convenient -- a kWh of cooling costs ~ 10 cents.
If you pay say $350 for tint, break-even will occur after 3,500 kWh of cooling.

Put another way: You have to save ~ 100 gallons of petrol to 'break-even'
If AC costs 5 - 10% more fuel, tint cuts usage in half, and AC is used for 1/3rd of the year, then
Break-even occurs at total petrol use of 6000 -- 12,000 gallons*
And by the way, choosing 50% heat reduction is true for the windows that have tint, but there is that pesky windshield ...

To summarize: Pretty much never unless you live in Hell, MS

* 100*10*2*3

 

you can't put comfort into an equation? if i lived somewhere cool - no issue for the few hot days. The one thing that your equation doesn't cover is the fact that the ICE is under less strain when the AC is only two notches up with tint vs. having the AC on full blast in the summer while sitting in the Prius (Hot House) no tint. The rear window lays so flat that it makes the car very warm. The AC is just cooling down a hot car? not terribly efficient.

 

Right -- no comfort here, just an answer to the money question.

The 'ICE strain' point is mostly moot. Max ICE drain is about 15 kW.
Now, what fool sits in their Prius in the open sun going nowhere ?! Go find some shade and chat with your neighbors. Or park facing the sun, put up a sun-shield on your windshield, and open the windows for ventilation.

 

But, doesn't the engine have to be generating waste heat in order to provide it to the HVAC system? I know my car will command the engine on much more during the winter in order to meet the demand for heat called for by the HVAC.

We're not looking at whether tint is an economical choice. We're looking at whether tint's properties will have a greater effect on energy consumption in winter vs. summer:

So, back to the original question. The OP's assertion is that the cost savings from additional solar gain to warm the interior of an untinted vehicle vehicle in winter is greater than the cost savings from heat rejection (and subsequent reduced cooling demands) in a tinted vehicle in summer.

X - Y = Z

Cost attributed to how much engine runs to supply electricity to cool vehicle without tint = x
Cost attributed to how much engine runs to supply electricity to cool vehicle with tint = y
Cost savings attributed to tint = z

B - A = C

Cost attributed to how much engine runs to supply heat to vehicle with tint = b
Cost attributed to how much engine runs to supply heat to vehicle without tint = a
Cost savings attributed to solar gain contributing to warming of untinted vehicle = c

Which is greater, Z or C?

Traffic in Four Corners is clearly different than here in Chicago. Just sayin'...

 

Chris, you said

The calculation answers that assertion.

Yes, the ICE will continue to run e.g at a red light in the winter if cabin heating is operating. That would be a case of *some* petrol use for heating but in the overall scheme it is very minor. This is true because most of the time the car has to use the ICE for movement, and because even at a stop some 85% of useable ICE power is shunted to the battery for later use.

That question is confounded by the local climate, but in general the above argument applies: very little non-waste heat is used in heating months. I'll also say in passing that at least in my experience the real energy hog related to winter heating is de-icing glass. I scrape snow and ice off my glass in the winter, but I see lots of people run cars for 15+ minutes *before* they drive to de-ice. Stupid behavior trumps all other considerations.

No doubt. I was talking about sitting in a parked car, not being stuck in traffic.

 

sitting in the car in the 95 deg summer heat is common in Los Angeles. )) Just drive and park on the 405 freeway and you will know what i mean.

 

enjoy the cool car.

 

FormulaOne Pinnacle here and the heat rejection was the reason I chose it. Great stuff. Had it installed on the windshield, too, and it makes a huge difference. Paid about $450 and worth every cent.

 

agreed the stuff can't be beat. what percent tint did you do? For the windshield what tint did you use - 80% Medico?

 

$430 for Suntek Carbon CXP. 80% front windshield and 18% for all other glass. Amazing stuff.