It wasn't all that long ago that the auto industry was under fire for its use of ozone-depleting chemicals in its air conditioning systems. To curb those fears, the older R-12 refrigerant was replaced with R-134a refrigerant. Interestingly enough, CO₂, long associated with harmful automobile emissions, is being touted as a desirable natural replacement for the chemical substances used today. In fact, the German Automotive Association has already chosen to use CO₂ as the next source for automotive air conditioning.

Another possible replacement for our current system is being proposed by DuPont and Honeywell. Known as HFO 1234-yf, it is a chemical refrigerant which is less efficient that current solutions. Safety concerns have also arisen regarding the flammability of the new chemical. For these reasons, auto manufacturers are meeting at an event next week in the appropriately hot climate of Phoenix, Arizona in an effort to make some sort of decision on how to proceed. We'll keep you updated.

While "sick car syndrome" has been known about for quite some time now, the recent rise in gas prices may be causing a resurgence of sorts to the odd but mostly preventable issue. The cause of the problem is the air conditioning of your automobile, which features an evaporator which can be a haven for fungi, mold and mildew. If the AC unit is not switched on regularly, a buildup of the unwanted guests can be blown out the interior vents of your vehicle, which can then cause all manner of illnesses to the vehicle's occupants. An odd odor which only shows up when the AC is first turned on could be a sign that your car is sick has mold buildup in its unseen recesses.

According to India Automotive, motorists are using their air conditioners less and less in order to curb fuel consumption. Regular usage of the AC, at least once a week, can prevent the problem. If the situation has already developed, the AC system can reportedly be cleaned by professionals.

[Source: India Automotive]

Even though the older types of refrigerant like Dichlorodifluoromethane (R-12) have been replaced with newer types like Tetrafluoroethane (R-134a), your car's air conditioning system could still be damaging to the environment. While not as harmful as the older refrigerants, recent research suggests that R-134a refrigerant is collecting in our atmosphere and could be contributing to global climate change. Therefore, the Mobile Air Conditioning Society Worldwide (MACS) has issued a press release, pasted after the break, that reminds consumers to be careful with their AC system maintenance. The refrigerant in your AC system can be captured, cleaned and recycled, and it's irresponsible to allow your refrigerant to leak out, simply refilling it when it's not blowing cold enough for your liking. Additionally, be sure that the technician working on your car knows it's illegal to vent it out into the air without recapturing it.

Recently, I wrote an article on the debate; do you get better mileage with AC on and windows up or AC off and windows down? A comment in the article said a Mythbusters episode found you could get better mileage with AC off and windows down. The way Mythbusters tackled the myth in that episode was just horrible. The myth was revisited in another episode, which I ordered and will review soon. So, what did they do?

They got an SUV and attached a sensor that estimates mileage by measuring air flow to the engine. They did 15 laps around a track, with a constant speed of 45 MPH, measuring mileage as they went. They did 5 laps with the AC off and windows down. 5 laps with AC off and windows up. 5 laps with the AC on and windows up. No laps for AC on and windows down. Here are the results.

1. AC off, windows up = 11.7 MPG
2. AC off, windows down = 11.3 MPG
3. AC on, windows up = 11.7 MPG

So, according to these tests, AC use does not impact mileage. Windows down hurts mileage about 5 percent. The better option is turn on your AC. Rolling down your window makes little difference at all. Apparently unsatisfied, they tried a totally new test, measuring mileage differently and even changed the variable of speed. This is important for the revisit which showed speed was very important. How they did second test is after the jump.

Fueleconomy.gov says "operating the air conditioner on 'Max' can reduce MPG by roughly 5-25 percent compared to not using it." Consumer Reports and Edmunds.com says you will lose 1 MPG. That's the low end of the government estimate of 5 percent if you have a car that does 20 MPG. Is it fair to call it a myth, as CNN claims?

Putting the windows down did not change mileage enough for Consumer Reports and Edmunds to measure any change in MPG. So, that's a myth. There is SOME gas savings and putting down the window does not burn a lot of gas. I guess the real question is how did the government get 25 percent reduction in mileage by turning on the AC? The AC on the car must have looked like this :D

I like AC and I hate the noise when I open the window. There are a lot more gadgets in cars today like GPS, DVD etc. It does take energy to recharge the battery. I am a big fan of recharging your battery with solar devices. I say have two batteries one for the engine and another for everything else. People could charge the batteries that powers the AC and radio etc by plugging it in at night.

Actually, now that I think about it, scratch that. Lots of people might not plug-in PHEVs. I doubt they would go through the hassle of independently charging the battery for the AC, heat, radio, etc. Okay, maybe hypermillers would do it. It might be cool if the car companies came up with hyper miler, bare bones edition of cars with little features like that. I would buy one. Even if it's a lower MPG car vs a hybrid.

[Source: CNN]