What's the best way of running the Air Conditioner

Very simple. Set on AUTO. Set the temperature you want. This is the best way to get the temperature you want. If you want to be more economical, use ECO mode and the car will adjust for efficiency.

 

Yep - That's about it...

 

We also tend to feel A/C serves the alternative purpose of cooling the HV batt so it's a good thing

 

I rarely use the AC for cooling, but when I do:

1. Set the ventilation system to AUTO, and AC button depressed.
2. Set ambient temperature high enough that the fan doesn't race. I try to avoid fan speed going higher than hallway.Typically that'll take a temp setting around 30C (86F).
3. As the cabin cools and fan speed starts to drop, lower the set temp., aiming for a target temp around 24~25C (75~77F).

 

I agree that the AUTO setting works quite well. If I get into the car when it's very hot or very cold, I'll sometime crank the temperature dial all the way over to LO or HI to get the maximum amount of cooling or heating as fast as possible - but for the A/C I rarely need to do this for more than 15 to 30 seconds. After that I set it to a specific temperature and let it do its thing. I'll occasionally change the temperature setting if, for example, I start driving in a different direction and the sun is now shining directly on me through the window, but generally speaking I just leave it and it works very well.

I generally leave the HVAC system set to "recirculate" on the theory that it doesn't have to work as hard when the air going into the system is near the same temperature as the air coming out of the system. It also helps to keep smelly exhaust out of the car (although even in recirc mode I believe the system still blends in a bit of outside air for safety reasons). When you do that the A/C runs at a pretty low level to dehumidify the air - if you turn off the A/C you'll notice the windows starting to fog up after several minutes. But that level of A/C doesn't seem to have any serious impact on fuel economy - mine is still comfortably better than the EPA rating (which itself is an awfully good number) so I'm happy.

 

Why turn off AC?


iPhone ?

 

i turn my fan on, then press the a/c on and off as desired, while continually monkeying around with fan speed and vent direction. what could be more efficient than that?

 

Air Conditionng use lowers your mpg. Constant use can lead to mould getting a foothold in the ventilation system.

Monitoring battery temps, I've seen no temp drop with AC use. This seems largely urban myth.

Mainly, I don't relish driving in a "personal climate bubble", at least not all the time. On a warm day, I'll just roll the windows down a bit, or all the way, depending on speed.

 

try that in vegas in july.

 

Exactly. What might work in mild Vancouver, BC (where Mendel lives) might not in muggy, hot Virginia (where the original poster lives). As others have said, I think running the AC is a smart thing to do in a Prius in terms of keeping the battery cool, and is a minor hit on MPG. lIf you can keep it at the higher range (say 74 degrees F), the MPG hit is further lessened.

 

I was responding to a question posed in #8, off-topic, I agree. What I said in #6 I've found to be the most effective way to use AC.

 

I read somewhere that the way to mitigate this is to turn off AC and run just the fan prior to stopping the car. For my CA temperatures 1 block or 10 seconds prior to my destination is enough to not get entirely too uncomfortable. It is said that this prevents condensation building up in the air pathways due to temperature difference. I've been doing this for years and it's helped.

 

Yeah, I find in practice it takes about 10 minutes, at least for the window fogging to abate.

The AC radiator (apologies for not recalling its official name) is akin to an icy glass of water on a hot/humid day, coated in condensation. Once the AC's shut down and the fins return to ambient temp, with myriad fins it takes some time for all moisture to disperse and/or find it's way out the drain tube.

 

probably depends on the climate you live in. we've never had a/c problems in 45 years of driving.

 

10 minutes? I'll take the smell. 1st world problem I guess.

 

The radiator-like part inside the dash that cools the air flowing through the HVAC system is called the "evaporator". That's because the refrigerant enters the evaporator as a liquid and leaves as a gas, cooling down dramatically in the process. It's like "canned air" - if you spray one of those cans for several seconds the can will get quite cold and can even get frost forming on its surface.

 

why is this not an issue with central a/c?

 

It can be - see Legionaire's Disease. Here's a story about an outbreak in New York last year that infected 100 people.

As far as I know automotive A/C systems have never been associated with this disease.