Auto A/C

Renocat · 11-05-2006, 10:57 AM

Just wondering if folks use the Auto A/c stting year round? I had auto climate control in my Subaru and I used it all year.

What is the most fuel effecient way to use the heat in the winter? Should I leave it on auto and let it do its thing? Should I turn the heat off at the beginning of a trip to let the car warm up(this is what my DH does) Or should I put on a reasonable heat setting and leave it there, not on auto?

tumbleweed · 11-05-2006, 11:31 AM

Last winter I tried to be in control of the system, AC, fan, outlets, etc. This year I decided to just leave it in Auto AC and let the system run it's self. The only advantage I can find to being in control of the system is that you learn how everything works. I have noticed no difference in mileage.

seasalsa · 11-05-2006, 11:35 AM

I leave it on, just set it and forget it. Unless you are really obsessed with MPG the 1-2 MPG hit is insignificant. TonyPSchaefer put it well when he said, "You can think of the A/C as a variable system. Basically, if allowed to do it's thing without human interference, it will work extremely efficiently."

SW03ES · 11-05-2006, 11:46 AM

Yep, just set it and forget it.

We are however extremely dissapointed with the quality of the Prius' auto climate system. I've had a lot of cars with auto climate control, and the Prius has the hardest time keeping the interior cool or warm. You're always freezing in the winter and sweltering AND listining to the loud fan in the summer.

Beryl Octet · 11-05-2006, 11:47 AM

<div class='quotetop'>QUOTE(Renocat @ Nov 5 2006, 10:57 AM) [snapback]344083[/snapback]</div>

Quote:

Just wondering if folks use the Auto A/c stting year round? I had auto climate control in my Subaru and I used it all year.

What is the most fuel effecient way to use the heat in the winter? Should I leave it on auto and let it do its thing? Should I turn the heat off at the beginning of a trip to let the car warm up(this is what my DH does) Or should I put on a reasonable heat setting and leave it there, not on auto?

[/b]

One of the posters here with the monitoring software (CANVIEW I think?) reports that the engine gets up to operating temperature quicker if you don't turn the heat on for the first few minutes. I just leave it set though, for the most part, and get in and drive.

deh2k · 11-05-2006, 12:23 PM

I mostly set it to a lowish temperature and forget it. It works pretty well. The one caveat is that I sometimes turn the AC off when I stop at a light and the engine it cold in order to let the engine shut off.

bryanmsi · 11-05-2006, 12:31 PM

Does the Prius use hot coolant for cabin heat like a traditional car, electric heat, or both? I have read that the Prius uses electric heaters, which makes certain sense and would match the electric A/C...but I have to believe that electric heat of any power would rapidly drain the battery. Is ICE heat also used when available? If ICE is used, wouldn't that also lower mileage?

8AA · 11-05-2006, 12:42 PM

The Prius uses both electric coils and hot coolant for heating. My understanding is that the primary function for the electric coils is to delay the ICE from restarting if the car is stopped and the coolant has cooled to the point that it really can't keep the cabin warm. I also believe that the electric coils might also be used to help warm up the cabin more quickly when you first start driving the car.

Why bother with conventional hot coolant heating when you have all that electricity available? It would take considerable power to electrically heat the car, and besides, once the engine is up to operating temperature, there is plenty of excess heat available for use.

**Tideland Prius** · 11-05-2006, 12:44 PM

It has an electric heater but it's really miniscule in terms of heat output. It's just there to buy us time until the engine warms up and provides us with heat.

I would leave it in AUTO and just set it in the lowest temperature that you can stand. Sometimes, if the engine still runs at traffic lights, I'll shut it off s that the engine stays off and turn it back on when the light turns green.

Renocat · 11-05-2006, 01:31 PM

Thanks guys!

I will be leaving it on auto a/c :P

11-05-2006, 12:42 PM	#8
8AA Senior Member Join Date: Feb 2004 Location: Maryland Posts: 492 My Car: 2004 Prius Model: Package: #9 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	The Prius uses both electric coils and hot coolant for heating. My understanding is that the primary function for the electric coils is to delay the ICE from restarting if the car is stopped and the coolant has cooled to the point that it really can't keep the cabin warm. I also believe that the electric coils might also be used to help warm up the cabin more quickly when you first start driving the car. Why bother with conventional hot coolant heating when you have all that electricity available? It would take considerable power to electrically heat the car, and besides, once the engine is up to operating temperature, there is plenty of excess heat available for use. __________________ '04 Salsa Red BC9 CN mudflaps (front only) • Back window fresnel lens • Inverted Homelink mirror • F37/R35 Lifetime MPG 51.6

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11-05-2006, 10:57 AM	#1
Renocat Senior Member Join Date: Jul 2006 Posts: 361 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Just wondering if folks use the Auto A/c stting year round? I had auto climate control in my Subaru and I used it all year. What is the most fuel effecient way to use the heat in the winter? Should I leave it on auto and let it do its thing? Should I turn the heat off at the beginning of a trip to let the car warm up(this is what my DH does) Or should I put on a reasonable heat setting and leave it there, not on auto?

11-05-2006, 11:31 AM	#2
tumbleweed Senior Member Join Date: Oct 2005 Location: Eastern Oregon Posts: 1,692 My Car: 2010 Prius Model: V Package: Adv. Technology Thanks: 33 Thanked 104 Times in 84 Posts Friends: 0	Last winter I tried to be in control of the system, AC, fan, outlets, etc. This year I decided to just leave it in Auto AC and let the system run it's self. The only advantage I can find to being in control of the system is that you learn how everything works. I have noticed no difference in mileage.

11-05-2006, 11:35 AM	#3
seasalsa Senior Member Join Date: Feb 2004 Location: Kent, WA Posts: 1,202 My Car: 2004 Prius Model: Package: #2 Thanks: 0 Thanked 1 Time in 1 Post Friends: 0	I leave it on, just set it and forget it. Unless you are really obsessed with MPG the 1-2 MPG hit is insignificant. TonyPSchaefer put it well when he said, "You can think of the A/C as a variable system. Basically, if allowed to do it's thing without human interference, it will work extremely efficiently."

11-05-2006, 11:46 AM	#4
SW03ES Senior Member Join Date: Dec 2004 Location: Gaithersburg, MD Posts: 1,509 My Car: 2004 Prius Model: Package: #9 Thanks: 6 Thanked 41 Times in 28 Posts Friends: 1	Yep, just set it and forget it. We are however extremely dissapointed with the quality of the Prius' auto climate system. I've had a lot of cars with auto climate control, and the Prius has the hardest time keeping the interior cool or warm. You're always freezing in the winter and sweltering AND listining to the loud fan in the summer.

11-05-2006, 12:23 PM	#6
deh2k Senior Member Join Date: Jul 2004 Location: New Hampshire Posts: 239 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	I mostly set it to a lowish temperature and forget it. It works pretty well. The one caveat is that I sometimes turn the AC off when I stop at a light and the engine it cold in order to let the engine shut off.

11-05-2006, 12:31 PM	#7
bryanmsi Join Date: Oct 2006 Posts: 53 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Does the Prius use hot coolant for cabin heat like a traditional car, electric heat, or both? I have read that the Prius uses electric heaters, which makes certain sense and would match the electric A/C...but I have to believe that electric heat of any power would rapidly drain the battery. Is ICE heat also used when available? If ICE is used, wouldn't that also lower mileage?

11-05-2006, 12:44 PM	#9
Tideland Prius Moderator of the North Join Date: Oct 2004 Location: Canada Posts: 19,620 My Car: 2010 Prius Model: N/A Package: Technology Package (Canada) Thanks: 229 Thanked 345 Times in 244 Posts Friends: 23	It has an electric heater but it's really miniscule in terms of heat output. It's just there to buy us time until the engine warms up and provides us with heat. I would leave it in AUTO and just set it in the lowest temperature that you can stand. Sometimes, if the engine still runs at traffic lights, I'll shut it off s that the engine stays off and turn it back on when the light turns green.

11-05-2006, 01:31 PM	#10
Renocat Senior Member Join Date: Jul 2006 Posts: 361 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Thanks guys! I will be leaving it on auto a/c :P