Most efficient A/C mode?

Genoz World · 06-29-2009, 10:19 AM

OK. i'll try 78 and from the sound of it, it should be fine.

richard schumacher · 06-29-2009, 12:04 PM

Do note that the battery system draws its cooling air from the passenger cabin. If the cabin is too warm for the average hairless ape then it may be too warm for the battery also. When a battery and its controls are too warm they have to throttle themselves, limiting the charge and disharge rates. It may actually be better for MPGs to use the AC.

Frayadjacent · 07-02-2009, 12:47 PM

Richard makes a good point. The battery system is cooled from cabin air, so if it's way too hot in there, the battery could be throttled to prevent overheating.

I always make the following recommendations for the hot summer months. These are universal for all cars. (adapted for the Prius here)

Get your windows tinted! It really helps.

Get a shade for your front windshield. It really helps. Use it religiously. It has a secondary benefit of keeping harmful rays off of your dash and other parts of the car.

Crack a window. Hot air needs to be able to escape the cabin.

Park in the shade where you can.

When starting a drive, roll down the windows to let the hot air in the cabin vent out. Leave them open for a minute or two once you start moving.

Turn the AC on and set it to vent/fresh air. Run it on fresh until the cabin air is cooler than the outside air.

Roll up the windows when the AC has cooled down enough.

After a few minutes, turn on recirculate so that the AC is only working to cool down the cabin air, which should now be cooler than the outside air.

With the Prius, at this point, edge the temperature setting up until you are no longer comfortable. One or two degrees lower should be the optimum setting for you.

zonie911 · 07-02-2009, 10:27 PM

But, but, I want to be comfortable!

ETP · 07-03-2009, 05:56 AM

Quote:

Originally Posted by zonie911

But, but, I want to be comfortable!

Comfort is over rated!

zonie911 · 07-03-2009, 07:53 PM

Oh, you guys-----just roll your window down and hang your arm out the window....... ha ha

icarus · 07-03-2009, 10:41 PM

Tint the windows!

We did our Subaru with black leather interior and it made a huge difference.

We have done the Prius with some cheap DIY stuff. It cuts down the heat gain dramatically. We also use a silver windshield cover while parked,, as we usually travel with the dog.

Icarus

ETP · 07-04-2009, 05:12 AM

My next project!

hyo silver · 07-10-2009, 11:57 AM

Quote:

Originally Posted by Frayadjacent

...Park in the shade where you can...

Yes, but be aware that when you park under a tree, you may get little droplets of sap all over the car.

Quote:

...After a few minutes, turn on recirculate...

Recirc is more efficient, but the lack of fresh air on a long trip can be a problem. I get sleepy without a steady supply of fresh air, which could explain why I feel truly alive only when exercising outdoors.

cycledrum · 07-10-2009, 12:07 PM

Don't dial a high temp (i.e. 80F) into auto setting ... could hurt your FE on a cool morning.

see this ...

Climate Temp Setting Seemed to Reduce Fuel Economy with Auto Turned Off

06-29-2009, 10:19 AM	#21
Genoz World ZEN-style living Join Date: Feb 2008 Location: La Canada Posts: 584 My Car: 2008 Prius Model: N/A Package: #6 Thanks: 1 Thanked 4 Times in 4 Posts Friends: 17	Re: Most efficient A/C mode? OK. i'll try 78 and from the sound of it, it should be fine.

06-29-2009, 12:04 PM	#22
richard schumacher Destination: Eschaton Join Date: Mar 2004 Location: United States Posts: 5,507 My Car: 2004 Prius Model: N/A Package: #6 Thanks: 99 Thanked 93 Times in 66 Posts Friends: 0	Re: Most efficient A/C mode? Do note that the battery system draws its cooling air from the passenger cabin. If the cabin is too warm for the average hairless ape then it may be too warm for the battery also. When a battery and its controls are too warm they have to throttle themselves, limiting the charge and disharge rates. It may actually be better for MPGs to use the AC.

07-02-2009, 12:47 PM	#23
Frayadjacent Resident Conservative Join Date: Mar 2009 Location: Austin, TX Posts: 327 My Car: 2009 Prius Model: Package: Base Thanks: 1 Thanked 14 Times in 14 Posts Friends: 3	Re: Most efficient A/C mode? Richard makes a good point. The battery system is cooled from cabin air, so if it's way too hot in there, the battery could be throttled to prevent overheating. I always make the following recommendations for the hot summer months. These are universal for all cars. (adapted for the Prius here) Get your windows tinted! It really helps. Get a shade for your front windshield. It really helps. Use it religiously. It has a secondary benefit of keeping harmful rays off of your dash and other parts of the car. Crack a window. Hot air needs to be able to escape the cabin. Park in the shade where you can. When starting a drive, roll down the windows to let the hot air in the cabin vent out. Leave them open for a minute or two once you start moving. Turn the AC on and set it to vent/fresh air. Run it on fresh until the cabin air is cooler than the outside air. Roll up the windows when the AC has cooled down enough. After a few minutes, turn on recirculate so that the AC is only working to cool down the cabin air, which should now be cooler than the outside air. With the Prius, at this point, edge the temperature setting up until you are no longer comfortable. One or two degrees lower should be the optimum setting for you. __________________ Wealth is the product of man's capacity to think. Who is John Galt? Last edited by Frayadjacent; 07-02-2009 at 01:19 PM.

07-02-2009, 10:27 PM	#24
zonie911 Senior Member Join Date: Apr 2009 Location: Nashville, Tennessee Posts: 529 My Car: 2009 Prius Model: N/A Package: #2 Thanks: 45 Thanked 14 Times in 13 Posts Friends: 5	Re: Most efficient A/C mode? But, but, I want to be comfortable!

07-03-2009, 07:53 PM	#26
zonie911 Senior Member Join Date: Apr 2009 Location: Nashville, Tennessee Posts: 529 My Car: 2009 Prius Model: N/A Package: #2 Thanks: 45 Thanked 14 Times in 13 Posts Friends: 5	Re: Most efficient A/C mode? Oh, you guys-----just roll your window down and hang your arm out the window....... ha ha

07-03-2009, 10:41 PM	#27
icarus Senior Member Join Date: Apr 2007 Location: quetico, on/bellingham, wa Posts: 1,207 My Car: 2007 Prius Model: Package: #7 Thanks: 9 Thanked 50 Times in 39 Posts Friends: 0	Re: Most efficient A/C mode? Tint the windows! We did our Subaru with black leather interior and it made a huge difference. We have done the Prius with some cheap DIY stuff. It cuts down the heat gain dramatically. We also use a silver windshield cover while parked,, as we usually travel with the dog. Icarus

07-04-2009, 05:12 AM	#28
ETP Ancient and decrepit Join Date: Apr 2009 Location: Crestview/North Florida Posts: 373 My Car: 2009 Prius Model: N/A Package: #6 Touring Thanks: 160 Thanked 3 Times in 3 Posts Friends: 57	Re: Most efficient A/C mode? My next project!

07-10-2009, 12:07 PM	#30
cycledrum Prius Aficionado Join Date: Apr 2008 Location: Union City, CA Posts: 1,419 My Car: 2009 Prius Model: N/A Package: #5 Thanks: 26 Thanked 42 Times in 31 Posts Friends: 4	Re: Most efficient A/C mode? Don't dial a high temp (i.e. 80F) into auto setting ... could hurt your FE on a cool morning. see this ... Climate Temp Setting Seemed to Reduce Fuel Economy with Auto Turned Off

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