HVAC Question................. Is AUTO the best setting?

Yeah I believe the cabin temp sensor is also a humidity sensor, 3rd gen and presumably 4th as well. Could be the programing was revised with 4th. When I'm fogging up my impatience goes up though, I can't wait on it.

FYI, 3rd gen set to to heat/defog, the AC compressor will run surreptitiously, without lighting the AC button. Maybe at lower watts.

 

That's true for PRIME as well. This happens either AUTO or Manual.

 

This is the list of relevant sensors in Gen 4:


This is the most intriguing control:


more details:

 

During recent cold weeks I haven't been very happy with the speed of front window defrost on my 2019 LE AWD-e. When it is cold and windows steamed up, I punch what look like "front defrost" and "rear defrost" buttons, keep it on Auto mode, and crank up fan speed to maximum. It works eventually, but quite a wait. It seemed faster on the old Toyota Matrix, where I could just manually set the air vents to use only the front window vents, and it would just blast it. But perhaps that is just wistful reminiscence.

The other thing I notice is, similar to the Prius C owner on first page, the ICE tends to turn on more than I'd expect, if the air heat is on.

 

Not just wistful reminiscence, from page 168 of 2010 Matrix Owner's Manual:



There were five conventional modes, with the fifth being all the air to the windshield. It could be argued that Toyota still provides that mode with the front defog button, but I'm not buying it. I'd like to just change the mode thus, without kicking in the air conditioning, and having the fan speed run way up.

(Manuals are downloadable from Toyota Tech Info, a great reference.)

 

I can't stand the controls in the Prius this time of year. Need heat in the mornings, cool during the day, heat again in the evenings (sometimes) - and the temp control is a little lever that, if held up or down, slowly makes its way warmer or cooler ... AND it pauses at 72, making it slower yet, as it passes by 72.

Every damned day I go through this. Between the severe lack of storage (storage that keeps items in the trays around turns), and the HVAC controls, this is a pretty frustrating car to have to live with. I like that it rides nicely, has torque when needed for passing, and the fuel savings - but Toyota screwed up the interior ease-of-living-with.

 

I get that. Comfortable as can be and a pleasure to drive, but taking away all those nifty little cubby holes was just mean spirited of them. Oh, and that stupid driver's door arm rest that's about four inches lower than my elbow. What's up with that??!!!

 

Those cubby holes are MUCH desired after using the Prius for a sales platform the last few months. I can't believe they moved away from one of the defining features of the Prius design to give us a worse experience. Everything in that center tray ends up at my feet.

 

Yeah, I don't put stuff there. But I do often slop drinks onto it from the cup holder. Probably not so great for the Qi charger in there that's too small and wimpy for my phone. LOL!

 

It's the only way to get heat - run the ICE. It'll come on instantly. But it may not be driving the car as such.

 

I don't understand why you need different levels of heat at different times ?
The idea of automatic climate control is, you set the climate control to a temperature you are comfortable in, say 69F, and the climate control maintains this, keeping you at your comfortable temperature. It doesn't warm up or cool down any faster regardless of what you set it at.

 

Pure heat to clean off the water vapor/condensation on the inside and outside of the front and side windows in the mornings, then AC the rest of the day to fight the heat.

I had to ask who would ask such a thing, but then saw you are a temperate Brit, lol. Would have also guessed a Californian. I live in a location with weather variances (only this time of year - this isn't an issue during the summer where it can generally stay on one setting) and high humidity.

I just got wondering, yesterday, if there could be a class action lawsuit over the design of that center tray. Its curved edges allow most anything to dump over them in turns - my cell phone and it's belt holder dumped off of it yesterday, and it got under the accelerator pedal. Had it got under the brake pedal, I would have been pissed - and possibly been in an accident.

Well, now you went and did it. I only just noticed - due to your post - how low that arm rest is.

This is a Wth interior design designed by old retired folk who don't put anything in their cars, who drive at 15 MPH under the speed limits at all times, and who are very, very short I guess.

 

Not sure what you mean by "pure heat" but to clear condensation you need the AC on. I just leave mine set to 21C on auto with AC on and press the windscreen demist button to clear condensation, which speeds up the fan and redirects the air to screen and front side windows only, then return to auto mode when the screen is clear. It doesn't heat up or clear the condensation any quicker if I set the temperature higher.

 

It helps clear the condensation much higher to have heat hitting it. AC, alone, but at a cooler temp (like what is comfortable) only delays condensation evaporation.

Again, you're in Britain where your neighbors believe you have winters and summers, humidity, etc. Perhaps try the rest of the world before putting out advice on how your car easily handles what little gets thrown at it?

 

Ok, I was just trying to be helpful, but what makes you the expert on what the rest of the world wants to hear, feel free to ignore my advice in your little corner of the universe and the let the rest of the world make their own mind up.
Are you in the only place in the world that has humidity?
I haven't seen posts from any other Gen 4 owners who have to constantly change the temperature during the day, perhaps there's something wrong with your car ?

 

What country are you in? - your profile only shows a number.

I generally leave mine at about 26° through summer, and about 22° in winter (I don't want the heater to heat me - I prefer coolth). Only time I generally change it is if I press the DEFROST button. Or - if I've just been doing something like mowing and want to cool me down with a higher fan speed.

 

Sometimes the conversation goes far deeper - and on many tangents on the way. Enjoy.