In SW FL we use a/c most of the time.
I have a mt Fit with a Scan Gauge, and now and then, switch off the a/c while driving. I haven't done it extensivly and recorded it, but it looks like it costs up to 5 mpg!
Has anyone done any more testing with a fit?
Being as you can feel a fair power increase, when accelerating and turning the a/c off, I assume it uses 5+ hp to run it. If it used only 1-2 hp, I doubt you would feel much difference.

 

Thinking about it more, I'm surprised you can feel the power increase, when turning off the a/c, and that mileage drops much.
Some marine, belt drive refrigeration systems, only use a 1/2 hp motor to run them.

 

I have a 2013 Fit sport with auto transmission. I would say that I do not feel all that much of a power decrease (acceleration, etc) with the AC on. It is much less noticeable than on my previous car, a Saturn SL2. With that, the acceleration was TERRIBLE with the AC on, and a very noticeable difference between on and off. So I have been pleasantly surprised with the Fit not being so noticeable. Of course, everything is relative, but as I said, I don't notice too much of a difference, at least so far.

 

2009 Sport manual. Using the calibrated Scanguage and cruise control over a 2-mile stretch of flat highway, average of both directions.

60 mph, no AC = 42.5 mpg
60 mph, AC = 38 mpg

 

Yeah, but if you didn't need the AC you wouldn't use it. Compare AC to windows open.

 

I dont think my use of AC has cost me 5mpg

I still manage over 40mpg while doing constant speed on the highway

I do think the number is closer to 2mpg if that. Honda doesnt allow the AC to be constantly on anyways, it cycles on and off without your knowledge

If you feel the air vents at idle after the AC system has been running and the car has gone to a fairly constant temp, you will feel the air sometimes get warmer for a little bit, then back to cooler. When you are holding a bit of a rev, its not as noticable

 

2012 auto sport, I would say 3-4 mpg less with a/c, good test over a few months 37 to 40 over same roads, very little traffic or lights, 50-60 mph 80 percent of time.

 

You shouldn't feel a power increase when accelerating because the ac turns off automatically anyway.

 

Really good thread...

I've never tried to measure it really closely but I certainly feel the AC kick on and take some power away. As was stated above, it feels like Honda engineered the compressor to switch on and off so it's not actually "on" constantly. Still, from the instant mileage bar, I'd say the AC adds 5% fuel consumption or about 2 mpg.

I have an appointment tomorrow to put ceramic tinting on my Fit. The Fit is a small car with big windows that let a ton of sun in, that thing gets hot fast. This tint should allow the car to stay cooler without the AC on so much.

 

Agreed. Any small 4cyl car is gonna have some parasitic drag when the AC compressor turns on and some noticeable HP loss (especially the tiny Fit engine). And yes, window tint should help keep things from getting too hot in this rolling greenhouse.

 

Ceramic tinting? I never heard of that type. Let us know how it is after you get it.

 

Ya apparently it's pretty new thing. The consensus is while it is more expensive, even near clear ceramic tint keeps out more heat then really dark dye type tints. Since I spend so much freaking time in the car I figured its a good investment. Driving to the bay like I do...you could be in the sun 5-6 hours.

 

You won't feel much of a drop in power because the car is programmed to disconnect the compressor if you call for enough acceleration. Basically: Drop everything else and get the car moving. Then it kicks on again, and you wouldn't notice it's been off unless you're doing this constantly.

I would say we lose 4-5MPG or so during AC weather. Less on the highway; more in city. So maybe highway goes from 41 to 38 and city goes from 31-26 or something.

Knowing how people drive in FL, I'd be surprised if you get my MPG

 

Yep I normally drive with my A/C on all the time but on one trip it was rainy and cold so I drove 700 miles on my normal road trip route with the A/C off and got my best mileage EVER for the same trip. It was about 5 mpg better with the A/C off on this long trip.

BUT the fuel savings to ME are not worth not having the A/C going when it's hot.