Newbie question for you veterans -- I've noticed that if you touch the Auto A/C button on the steering wheel, when you go into climate control, it's turned on (intuitively enough) both the automatic climate control, and the air conditioner to on, regardless of how you had it set up before. My question is... with the Air Conditioner set to on this mode, does it actually use the air conditioner (condenser) all the time, or just when the car deigns it necessary to cool the vehicle down? Thus far, I've gone into climate, and made sure the A/C button is unselected, but the temperature control is still turned on... and that seems to work... but I'm not sure if I need to do this, or if the system is smart enough to lay off using the actual air conditioner when it's cold outside (or at least when it doesn't need to actively cool the cabin down from a higher temperature.) If it's not going to impact my mileage by running the real A/C system all the time, I'd like to leave it on so I can "set it and forget it," but I'll keep doing what I'm doing now if not actively deselecting A/C on the climate screen means the air conditioner (and not just fan) will run all the time. Thanks!
I have also wondered about this. However, I can say that the last few days I have needed to heat the car, and if the compressor is "enabled" than the motor will stay running at a stop. If I switch it off, then the motor goes off as well. I therefore concluded that it stays on in automatic. I would love to find Im wrong here!
Guys I just don't think the compressor is running when the car is actually heating everything else is just too advanced and too designed to be energy saving to believe they'd do something like that. I think the thing that makes this question come up at all is the fact that they call the climate control system the Air Conditioner....if they called it climate control would we even wonder about this??
[font=Comic Sans MS:4a7ae9a4e3] That certainly makes sense. But consider this: It's recommended that the A/C compressor be "On" while heating the car if the windows are fogging up. The A/C compressor removes the humidity from the air and helps defog. (Is that a word?)
Isn't that why we have the "defog" button on the steering wheel and/or climate control screen? If you start to fog, pressing that button overrides the climate control,t turns on the front panel blowers, and activates the A/C compressor to help deal with the humidity issue that causes fogging inside the window.
If the climate control is on auto the windows will not begin to fog. The Defog buttons are for use when you get into the car and the windows are fogged or frosted.
This is a feature of most cars with Auto A/C. The good news is you can have it changed (among other things)by your dealer via the Toyota Scan Tool. It will allow you to select Auto A/C without automatically engaging the A/C compressor if it was not already engaged. The compressor cycles on and off to reach and maintain the desired temperature whether heating or cooling the air. It prevents window fogging because it is actually removing moisture from the air. The only time the compressor will not run (even though the A/C icon is lit) is when the ambient temperature is below 38F. This is to prevent damage to the system because the refrigerant will become too cold. I hope that helps a bit. Best, Pino
Isn't the air conditioning compressor on the European model of the Prius electrically driven? Before the weather turned, I have had the air conditioning on full blast in 100+ degrees Fahrenheit ambient temperatures and the ICE would shut off every time that I came to a stop as long as the traction battery was sufficiently charged.
Does the electric a/c unit in the Prius actually use a compressor? I was discussing this with a friend today and he mentioned that some A/C systems use electrical resistance to create a heat transfer. In fact, the refrigerator on most RV units don't have a compressor. If the Prius does use a compressor, does it get its power from the main electric motor or would it have a separate motor?
The Prius uses an electric compressor which is driven by an integrated motor. Denso Electric Compressor for New Prius (Click here)
If I may add another question to this thread. In the Camry, if you press AUTO, the system will go into auto mode and the A/C will be activated (nothing surprising here). Same for the Prius. However, in the Camry, I can turn off the A/C and still have it in auto mode. I can't seem to do that in the Prius. It seems to go into manual mode if I turn off the A/C. Does anyone have any ideas how to set it in auto with the A/C off? I realise it has a humidity sensor (or so I read somewhere). Does that make a difference?
You can, I believe, keep the Auto mode on, but turn the A/C system off... but not with the steering wheel button. If you go into the Climate screen, with auto mode on, you can touch the A/C switch, and the yellow "selected" bar up top will disappear. The Auto A/C button on your dashboard display will stay lit, though. If you turn on the front window defogger and then turn it off (by hitting the defogger button again), then go into Climate, you'll see that it's respected your settings and restored everything as it was before. But if you hit the Auto A/C button on your steering wheel to turn it on, it's back to auto on and A/C selected. It's that observation that sparked this thread, wondering if the A/C gets used all the time in Auto mode, unless you manually de-select it.
Unless you select the "Defrost" mode, the air conditioning compressor is thermostatically controlled and is automatically turned on and off on as needed basis.
Many thanks... I suspected as much, but wanted to be sure before I was waisting energy on actively air-conditioning the lucky-to-make-double-digits © air I'm driving in.
Totalshock: ahh I see. Thanks! 10132003: So if the climate outside is comfortable enough so that A/C isn't necessary, I can still leave it in auto a/c mode and not worry about it affecting the mileage or whatnot?? nice!
This discussion raises the question regarding heating cabin air. We, at least in NA, typically use the phrase "air conditioning" to mean cooling. But what about heating the cabin? The engine coolant is not always available for routing through heating coils with the Prius as it is with normal cars. Is it possible that the compressor is functioning as a heat pump, ie. with both a cool cycle and a heat cycle? If so, then the system would always be enabled in AUTO, with the thermostat controlling the decision to heat, cool, or remain in standby depending on cabin temp. The Denso article only mentioned "air conditioning." However, literally speaking, you can consider that cabin air is also being conditioned when it is heated. Does anybody own a Prius Shop Manual? I assume the section on cabin climate control would describe how the system is designed to operate....? Hank
no. in some circumstances it is possible to have both the air conditioning and heater on at the same time when using defrost. realize that because the compressor runs only when a demand for cooling is called for means that although the air conditioning system is on, it will be using minimal energy.
Oh, OK. I was thinking that heat strips being an inefficient use of power, Toyota would have specified something more efficient like a heat pump. Probably the cost of a pump is still too high though....? Thanks, Hank
