however I seem to remember my father saying that the a/c caused a 3-4mpg drop. Nowadays I dont think the a/c hurts fuel economy as much, but maybe it does, i don't know.
Depends more on the vehicle than anything. A 3cyl SMRT car will see a reduction more than an 6 or 8cyl Dodge Charger
Global Warming.
@bscar Yes, even Comsumer Reports told its readers to expect a 4 mpg drop in a full size car when equiped with A/C.
In the 60s I worked for a boss who bought his wife a Mustang, that hot new pony car designed by Lee Iacocca. Well, she wanted automatic and A/C, but also wanted a 6 cylinder engine. That combination made for a very sluggish and unsporty car. I drove it on some occosions and found it snail-like compared to my Dodge Dart GT with the V8 and 3 speed Torquflite transmission.
I restored a 1987 Volvo 740 and converted it to R-134. It came out of the dash at about 38F and did a good job, but did not freeze the car. My current Hyundai Elantra 2012 can get cold, but only running on high speed. A couple things I noticed - engines are much smaller and running a large compressor would steal economy. Also, the dashboards are more exposed under longer, aerodynamic windows + my dash is black plastic. I am sure that heats the air. Lastly, my roof has little insulation and I think that contributes as well. My best guess is smaller, lighter, more efficient cars with smaller AC systems and minimal insulation - especially on economy cars. SUVs have rear AC, sound deadening insulation and larger components I am sure.
Even with R134a there are some models with pretty cold AC. My Mustang for example has the same A/C compressor as the Expeditions and Crown Vics of the same vintage with much larger interiors/ Needless to say thereās no shortage of cold air coming out of the vents. The most powerful HVAC system Iāve ever wittnessed first hand was that of the Ford Windstar, those minivans has many shortcomings, but becoming a meat locker in a matter of minutes wasnāt one of them. I remember I had borrowed momās Windstar one night, myself and 5 other cohorts were going to a concert. It was a hot summer evening and the concert was outdoors, when we left venue some guys in the back requested AC. So I cranked up both the front and rear A/Cs to their maximum settings, and not more that 2 minutes later, I hear from the back āGod dm, thatās what I call fk*** AC!! Turn it down some.ā
You could get a Chevy Vega with factory AC. The compressor was HUGE. When you clicked on the ACā¦the motor would almost stallā¦and it would be a dog to drive.
I tested a little 3 cylinder Chevrolet convertible (I canāt remember what they were calledāthey were made by Suzuki with the Chevy nameplate). It had an automatic transmission and air conditioning. I think one cylinder was needed to run the air conditioning, one cylinder was needed to run the power steering, alternator and water pump leaving just one cylinder to move the car.
The only new company car I ever drove was an '82 Escort (first or second year for the model I think) with a 1.6? liter 4 banger. They let me choose between an automatic and 5 speed (and the colour) so I naturally went for the standard in gun metal grey with red naugahyde? interior. AC was an option I needed too because I was in āwhite shirt and tie, travel to meet the public modeā most of the time. The AC was cold enough to freeze your ass to the seat but I also remember having to shut it off before downshifting in order to pass anything (which was a hair raising enough experience even without the compressor diverting power). I fondly remember driving the bejeesus out of that reliable (and fun) little car for four years without anything more than regular maintenance and cleaning.
"Why was A/C back in the 1970ās so cold?"
Global warming?
When itās hot out with high humidity even a perfect a/c system will take a good 10 min. to cool things down inside a car that is over a 100 degrees inside. If your looking to decrease the cooling time it takes for the A/C system use a reflective shield inside in the windshield or park in the shade. Also, drop the windows down a few inches initially to let out the hot air build up. This allows the A/C to drop the temp faster.
It is not the refrigerant. R-134a boils at -15.34F it has the ability to freeze the evaporator to a solid block of ice.
The origin of that myth is from retrofitting from R12 to R134a. Systems that cycle the compressor by temperature worked at the same temperature. Systems that regulated the evaporator temperature by pressure were not as cold unless the pressure that it was regulated to was changed. At 30 psi R12 is 32F, R-134a is 34.5F.