Window "tint" saves fuel through reduced AC load (duh, but nice to see quantified)

[MetroMPG]

Anyone else see this?

I don't think it's specifically about "tint", but I put that in the title becuase it's shorter than "infra-red reflective glazing".

"Over repeated UDDS cycles, the Sungate EP glazing reduced the air conditioning power and resulted in an increase in fuel economy," said John Rugh, Senior Mechanical Engineer for NREL. "The adjusted, utility factor-weighted fuel economy increased from 36.8 to 42.9 mpg for the Sungate EP thermal load case, while the adjusted, UF-weighted electrical energy consumption was roughly equivalent."

From: PGW Automotive Glass Improves Fuel Efficiency Up to 6 MPG, Reduces CO2 Emissions for PHEV

Window tint should be in the mods list. It didn't occur to me before because I don't have AC, and probably wouldn't run it much, if at all, if I did. But everyone's different.

[Daox]

Interesting. Guess you should add it to the list.

[TomO]

Tint would appear to reduce the need to roll down the windows in a non-A/C equipped car as well. As it would reduce the amount of heat beating down on you as you're driving and as the vehicle is parked in the sun.

[QuickLTD]

Am I wrong? Since most automotive A/C units are not temperature based systems like home units, once its on... it is on. Same engine load wherever the knobs are turned. Max AC just moves a baffle recirculating cabin air and the temperature control knob also just controls the mix between the a/c cooled air, air in the heater box and or outside/cabin air. Climate controlled cars like mine work on the same principles except the computer controls the mixtures. None of this should have anything to do with the compressor cycling. Turn on your a/c in 30deg F weather and see what I mean. It still turns on and cycles regardless.

The only thing I could see the tint doing is making it stay cooler longer if you wish to manually switch the a/c on and off every 5 minutes or making it cooler in general so you dont need a/c

If I am incorrect as to the operation of automotive A/C please correct me.

Dean

[Cd]

( Window tint results in a cooler car when you get into it on a hot day. So you use the A/C less. That saves fuel . Unless I missed something, that is where I think the increased FE comes from.)

Cars always look cool with tinted windows. Keeping the car cool ( literally ) is just the icing on the cake !

[QuickLTD]

you're in texas im in FL so we know all about 9 months of a/c lol

[robbiewt]

I have 50% tint on my door windows and 35% on the three back windows. I also have a reflective windshield shade. That little car still gets pretty darn hot while sitting in the sun.

[botsapper]

Lowest (FE & comfort) hanging fruit, especially here in the Southwest. Just make sure your shop knows your state's darkest allowable tint levels for the different window panels.
An additional efficiency mod list is paint color/reflectivity property. White/light silver metallic roofs (Minis, FJs, etc) or white/light silver met. vehicle body paint always helpful for cooler cabins. Also, higher night time visibilty = better safety.
Another trivia but black/dark cars need more car washes than white cars. Detailers report much higher frequency of appearance maintenance of darker vehicles. White paint, less water use. Better resource efficiency.

[MetroMPG]

Dean - seems the vehicle they tested has AC that varied load based on cooling requirements:

"Over repeated UDDS cycles, the Sungate EP glazing reduced the air conditioning power and resulted in an increase in fuel economy"

Not sure what kind of car it was. The article didn't say.

Darin

[tasdrouille]

The adjusted, utility factor-weighted fuel economy increased from 36.8 to 42.9 mpg

Seems overestimated to me. 16.5% FE increase from tint is ridiculous.

It's sub 3% year round average for sure. But still, at $3.5/gal it takes more or less 50k miles to pay off.