AC commits pre-meditated murder on MPG

Combine the MPG hit from AC with the hit from short trips where there car spends most of its time warming up and it is easy to see why some people can barely get 40mpg.

 

But barely getting 40mpg on such trips is like only saving 5 children from a burning building. It's still pretty darned good.

 

I cannot argue that, my friend.

I just like teasing our information from the data to explain why some people are not getting the MPG they think they should. Some will decided to make changes to their driving habits and some may just decide that they are ok with the loss now that they understand why it occurs.

 

some answers about this
#1: if your a/c refrigerant is low the compressor will work harder to try to cool, ( pull more AMPs from your battery) to try to cool you, at the same time over heating your compressor shorting its life.

#2: if your car has been in a accident and the body shop put on a cheap low quality non-OE condenser the high side pressure will skyrocket, needing a lot more power to run it.

#3: if the a/c refrigerant is over charged this will lower MPG by raising high side head pressure( use more amperage to drive the electric compressor )

#4 the DENSO a/c compressor and the Toyota a/c system is a vary good one, BUT!! its vary touchy about under or over charge, what kind of oil to use, moisture in the system, air in the system... even many of the Toyota dealers do not fully understand the new electric a/c systems. the ols a/c book and old school DO NOT APPLY to this car!!!