Staying Cool AND Getting Great Gas Mileage

great thread!
i run it manually. depending on how hot the car is when i get in, i do the open rear window thingy, always in recirc and start with a comfortable fan speed and keep reducing it as much as possible as the car cools down.
i'll even turn the a/c off and on if it gets too cool at low fan. i see a 1-4 mpg hit depending on outside temp and solar gain. i don't have tinting.
i'm also considering filling a cooler in the morning with frozen bottles of water.

 

I mostly run it manually also, except for those times when I select "Auto" and let the computers in the car do the work for me (I worry about the TractionBattery being comfortable). It's similar to when I visit my friends who have a dog - when I'm in her company, I rarely bark as there is no need to, since her bark is much louder and far more effective than mine! (…it's all to do with her evolution!)

 

Depends on windows open or closed.

Most, if not all modern cars have dramatically increased drag with the windows down.

A typical AC compressor will consume ~5-8HP, don't know the rating on the Prius electric scroll, but you aren't getting that for free!

If you run with the windows up and AC off, then you will save the power that it takes to operate the compressor, that is for certain. How much it affects FE, is quite another question.

 

I am very thankful and fortunate to own a new Gen4 Prius. And I'm amazed at the great MPG I keep getting. To be honest I'm not even concerned with the gas mileage.

For 7 months, I have run the AC almost constantly (set at 65-68 degrees) and I'm averaging a steady 62 mpg in the city. That's fine for me. Couldn't be happier. This car has greatly exceeded my expectations.

 

I mostly don't use AC, would guesstimate it's mpg impact at 5%.

Our usage in summer is mainly if the wife deems it necessary, following some diesel. And winter, when it's rainy and we're seriously fogging up.

In the latter I first try just setting mode to Heat/Defog, which will use a bit of surreptitious AC, and not aggressively, even when AC button is not pushed.

But yeah, there's no free lunch.

 

Run it on auto pretty much all the time. I don't find that I need to keep it that cold (78-80 in the hottest part of the summer, which is hot here in Dallas, maybe 76-78 when it's not as hot) for it to feel comfortable though. Since I haven't tried it without, I'm not completely sure about effect on mpg. I seemed to have gained about 2 mpg since the temperatures have cooled off a bit though so maybe we will say that.

I decided being comfortable in the car is worth the mpg hit. I am more stubborn about the heater though.

 

Same here in central Oklahoma. When I use the A/C I run it a manual mode set to 78 Deg F, recycle air setting and on the lowest fan speed once the car cools off. I get mid to high 40's MPG around town during the heat of the summer, which for our Prius v Three is very good as far as I am concerned.

As far as the heater is concerned my wife likes to be warm. We have only used it a couple of times in the early morning while on a trip to Colorado 10 days ago. Luckily we head south for the winter so we will not use it much, or at least I hope not...

 

A lot of people set recirculated air as the norm. I find that somewhat unusual, only rarely use recirc, and just temporarily, say following a diesel, or going through dusty construction.

 

I use the air "recirc" button all the time. It is so dry and dusty here. You wouldn't believe all the dust and dirt on that white paint... a day after I wash it, there's visible dirt on the car. I sure don't want to drive around with the windows down, or vents open and have all that airborne dirt coming inside the car.

The big black Darth Vader screen attracts a lot of dust. And I'm also concerned about dust going into the hybrid vent opening. Maybe I'm being a little too picky, being a first-time Prius owner. I'm glad that car has good AC. I use it and enjoy it. Anything over 40 MPG is good!

 

I do not know. Look at that nice scene in your avatar. Do you walk that beach in a space suit, lol. Anyway, two sides to each coin I guess. How about this: just set the system to "auto", what does it do? If you're running AC, likely a little recirc at the outset, then switch to fresh.

Myself, I just (cover your ears): roll the windows down.

Some threads, with varying opinions:

Outside Air vs. Inside Air Mode – What's the Difference?

Blog Post | Recirculate versus fresh-air: Tom and Ray settle one family's bet. On the line? A steak dinner. | Car Talk

How high can CO2 levels reach inside a car when air-conditioning is on recirculation? - Quora

'Recirculate' button cuts drivers' exposure to air pollution, study says - latimes

 

I drive in pretty heavy traffic for most of my commute, so I use recirculation not to smell the other vehicles. But sometimes I will turn it off when traffic is lighter or I'm in a residential area, etc to get some fresh air. Especially when the outside temp is pleasant.

 

FWIW I have always used recirculated air when I use the A/C in whatever vehicle(s) I have driven. This blurb from my owners manual also notes using recirculated air will help cool the car effectively.

 

As noted by Mendel I also roll the windows down especially this time of year when I drive around town. Admittedly a smaller town than Dallas where I will be this weekend for the OU - Texas game...

 

Don't let the beach scene fool you. California is a desert. And I am about 8 miles inland from the coast.
Going up to 90° again this weekend, and hot blowing dusty Santa Anna winds coming off the desert. I knew I shouldn't have washed the car yesterday.

Perfect earthquake weather.

(I get plenty of fresh air when I park. That's when I roll down my windows... and air out the cheeseburger smell.)

 

Ugh.

 

Driving in PWR mode.
AC blasting.
No hyper-mile driving.
Constant 62 MPG.
Egg McMuffin in right hand.

It's all good.

(Thanks to Mr Toyoda.)

 

....if you hyper-mile guys traded up to a Gen4, you'd probably get 80 mpg! And never be concerned with the AC and gas mileage.

But this old fat dude is fine with my current mpg. And I keep 2 "Febreeze" air freshners in the car so the little woman doesn't complain about pepperoni smell.

 

Let's move on, and argue about more important things, like...

"What angle is you're seat back set at???" and "Do you rest your left elbow on the door?"