[jcp123]

Originally Posted by MeteorGray

I drive my Mazda3 mostly on long commute trips on the highway, and as already noted, I can't tell the difference in fuel mileage with and without the air conditioner. I try to see evidence of it on the Scangauge via its instantaneous mileage readout, but the variations of highway, wind, etc tend to mask any contrast between "on" and "off" mileage differences for me. I know the air conditioner takes energy to run, but it's small enough that I can't "see" it, either on the Scangauge or at the fuel pump.

One technique I use when I don't have a passenger is to push the button that controls the air conditioner's compressor on/off activation. I leave the thermostat/temperature setting on "maximum cold," and when I get cold, I push the button to turn off the compressor and let the temperature gradually rise until I'm too hot, then repeat the cycle. When I push the compressor button, I can't tell any difference except for the temperature of the air; ie, I can't "see" whether the compressor is on-or-off on the Scangauge or "feel" it via the ambience of the car or in any other way to indicate the compressor is running.

One reason I use the compressor's on/off button in this way is the fact that at one time in automotive history (and maybe today in some cars?), some genius figured it was a good idea to let the compressor run all the time and use the engine's hot water to moderate the cabin temperature. It works, but at a higher fuel price. A workaround for me was the compressor on/off technique. I don't know if it's better for fuel economy on my Mazda or not, since I suspect the Mazda's compressor cycles as needed and doesn't use the "hot water" idea. But, is it better for FE to use the on/off technique or just set the temperature/thermostat at the desired temperature level and let the compressor cycle? Don't know.

In any case, I'm too old to drive around in a tropical climate while being hot and sweaty with the roar of hot-and-humid-and-dirty air blasting through the car for several hundred miles at a stint. I just can't take that anymore. Nosir.

Your Mazda is a lot newer than my old beater. I would expect better a/c abilities. My Ma’s ‘06 Mazda 3 is a mystery, I don’t think I have ever driven it. But my Civic AC sucks, my Ma’s former ‘04 Sienna a/c sucked, and the worst of all was my old Toyota Echo, the only one I checked with an actual manifold setup.

So, given that my dataset is old, i’ll say that 90s/early 2000s a/c royally sucked.