Question about using the a/c

Among the MiEV's quirks is the way the a/c settings are set up. The temperature dial has a neutral spot at 9 o'clock and if you want warm air, you turn the dial clockwise, if you want cold air, you move it counter clockwise. In most cars if you just want unheated/uncooled air from the outside coming in through the vents you turn the temperature dial all the way to coldest. On the MiEV, you keep the dial in that neutral 9 o'clock position.

According to the car manual, if you want to use the a/c, you move the dial from the neutral position to somewhere along the cold range, depending on how cool you want the air to be. But that seems odd to me. Doesn't an a/c unit just kicks out cold air? If you put the temperature dial somewhere short of maximum cold, aren't you just mixing outside air with the cold air generated by the a/c? Isn't this in effect wasting energy since the a/c will work just as hard no matter how much outside air is mixed with the cold air? In addition to keeping the fan on low, what temperature setting is the most energy efficient way of running the a/c?

Tony

You can also have air conditioned hot air, the a/c dries the air in the cabin, for example, if you need to defrost the inside of your windows because you got into the car with a wet coat from the rain and it's cold outside, you don't want a blast of air conditioned cold air defrosting your car, you want it to be hot(comfortable) and dry to clear the inside of the glass of condensation.

What I am trying to say is you can have the air conditioning on at the same time as the heater - full or anywhere on the temp select dial.

Finally . . . . a subject I have some personal experience with We use the A/C *lots* down here in Biloxi!

Like so many other things on the car, the engineers tried to minimize energy usage by making this as 'automatic' as possible

If you press the bottom knob with the A/C on, you've set the inside/outside air selection to inside (recirculate) only. Of course, pressing the center (fan speed) knob turns on the A/C and if you rotate that knob fully CCW you will set the fan speed in 'auto' as well. At that point all you need do is adjust the top knob down one or two or three clicks from the center 9 o'clock position to the most comfortable setting for you and the car will do the rest - Try to keep you comfortable while using the least energy to do it. Works pretty well for us

Pressing the top knob will give you 'max air' and doing so for a minute or two when you get into a hot car really cools it off quickly - You can select outside air by pressing the bottom knob while you're doing this as the outside air may actually be cooler than the air trapped in the hot car. Press both knobs again after a minute or two and you'll get everything back to 'normal'

As an aside, pressing the center knob (A/C on/off) while watching the range remaining number on your instrument, you'll get a rough idea of what driving that far running the A/C as it's currently set up is going to cost you for the given outside temp. Up until today (93 degrees here) I would have said that the energy usage was fairly minimal, but clicking it from on to off today showed we would get an extra 8 miles of range if we left it off . . . . but at 94 indicated by the car's thermometer, we weren't going to worry AT ALL about those 8 missing miles! :shock:

Don

Thanks guys - as someone for whom air conditioning is still a novelty, I appreciate your explaining the subtleties of this system.

Thanks Don, so it sounds like keeping the temp in the low/cool range does save energy. Good to know. It was 85 degrees here yesterday and it isn't even June yet.