Using the heater in winter

[Trewithy]

I normally set my CC to 19 in summer and 20 or 21 in winter, run it on Auto and never switch off the AC.  But I have been wondering is there a more efficient way without sacrificing too much comfort.  I guess it is best to keep the temperature low so the engine cuts out sooner.  how about running it on the Econ setting or turning the fan speed to its lowest setting or setting the air flow to feet or feet and windscreen. Just leave it on Auto and let it do its own thing, recirc?  I'd be interested to know what you do. 

[Stopeter44]

From my, non Toyota, experience I think it's better to run CC all the time, so, like you, I set 21 usually in cooler or cold weather and 20 in hotter weather and sometimes  lower when it is very hot (35°C +). I've only had to recharge the AC coolant once in 6 years of use, and even then I could have waited.

From what I can glean from the manual, for the Yaris, Econ will mode will change some of the draw, for want of a better word, on the ICE and might give better overall fuel economy under certain conditions. Since I have yet to live with the Toyota Automatic Climate Control, I'm thinking that it would be marginal under most, let's call them, temperate conditions, but when the going gets tough, then comfort would suffer.

Edited November 3, 2021 by Stopeter44
clarity

[Cyker]

I always leave the AC on and have it on Auto, but approaching the car's first winter I've taken to just turning the whole HVAC off, as even if I set it to a warm temperature all it does is run the engine more and the car never really warms up... I guess that's the price of running an efficient car, as there's no waste heat to warm the car up! My old diesel Yaris had the same problem - Could get half-way to work before the cold engine light went out if it was particularly cold!  

I'll turn Auto on again once the engine reaches operating temp, but below that it just wastes fuel...

It's a shame they can't just run the AC system backwards to heat the car like some EV's do now  

[Stopeter44]

1 hour ago, Cyker said:

I always leave the AC on and have it on Auto, but approaching the car's first winter I've taken to just turning the whole HVAC off, as even if I set it to a warm temperature all it does is run the engine more and the car never really warms up...

<snip>

It's a shame they can't just run the AC system backwards to heat the car like some EV's do now  

Which is where the heated seats would appear to be a viable option, they help keep your back, at least, warm until the car warms up. As far as I can tell it's the basic option in EV's when there is no heat pump.

I was hoping that the Toyota automatic CC was able to do hot or cold like a heat pump, since it is driven electrically, as do most respectable AC units for the home (not automatically, generally). In one of the Car Care Nut videos, and I don't recall which one, he talks of a heating element, akin to a hair drier, in the Prius CC system. He does go on to say it's better than nothing, but not particularly effective.

[Cyker]

Yea, for some reason I thought the Mk4 had a PTC heater (Positive Temperature Co-efficient heater, fancy name for a hair drier heater coil  ), but it definitely does not!!

 

[preperationlaunch]

On the mk3 Yaris, ECO mode will run the engine less for heat. Instead, it'll turn the fan down, and tolerate a lower coolant temperature.

Turn ECO mode off and it'll suddenly fire the engine up immediately until it has decided the coolant is hot enough.

Some Toyota hybrids do have the PTC heater, I think the mk3 does, but it's only a couple of hundred watts. It takes the chill off rather than heating.

[TonyHSD]

Ok, I do not like AC to dry my air and I only use AC in hot summer days, sometimes I never turn on ac for months 4-5 and more and I never had any problems with any car to date. Modern ac compressors do not sleep and always has some very little work they do, this I know from an ac specialist and make a lot of sense to me. No need to run ac on just to keep the system maintained as this is done by the ac ecu itself. 
Now for the heating settings:

I never keep HVAC in auto mode because of the ac reason and in winter time I always set the temperature at 22C° blowing fan at speed 2, air intake from outside and blowing air stream towards feet and windscreen, AC off, doing so guarantee me hot and dry air exactly where I need it and the automatic temperature control take care of the air temperature and adjust itself accordingly. 
In summer time I keep the same temperature settings  of 22C° same fan speed 2 and same air intake from outside but I do change the air flow to be towards the feet and middle of the dash, not towards to windscreen, doing so prevent windscreen misting after an AC use as I do use air conditioning when necessary. AC does uses a lots of energy from the hybrid Battery and when cold it’s absolutely no need to have it ON unless you really want that, except when driving on short trips in damp rainy weather, then ac helps to dry your cabin and windows faster and this is only when I use ac outside the hot sunny days. That’s how I am doing for more than 20 years and works for me the best. 
Regards