MyX1:

How factual is this Info?

NigerianScholar:

Dont mind some people. Putting your ac on ' HI' just consumes battery. Because d fan wuld b rolling faster. Just like putting on d car when when the engine is not running. You are only stressing d battery.

suco01:
Frm a car AC technician dat i asked, he told me d more u change d car AC frm low to medium to high and d engine change sounds, it consume more fuels dats y u see pple mostly stay on low to maintain a cool environment in d car to avoid more fuel consumption... To confirm hw true is dis, i disconnect my Uncle Hyundai H1 fuel hose frm tank into a 1litre fuel jerican and i put d mini bus ignition on and put d AC on low and i time it, i repeated d same 1litre fuel for medium and Hi. I dicovered the fuel consumed while d AC is on Hi vanish very fast than when in Low. Bt i dont knw 4 other cars oo. I rest ma case

Sunymoore:

Bro, Fan at high speed consumes fuel, but the amount of fuel consumed is so small that it can be negligible...
My car only have a single fan, and that fan Cools the radiator and compress the AC. It might interest you that, even if I didn't engage the AC, sometimes the fan comes at full, and no fuel drain is observed, and if the AC Is engaged, the fan stays at full all the time...

FTBoi:
but it's only when the compressor is on you feel the sudden jerk of power drain in the engine. but with just the blower on, you wouldn't notice anything. i've experienced that many times......it's funny how people come here to tell otherwise..

achu442:
I no like too much argument.
Put 20 litres of fuel,Drive from Lagos to Ore with your AC on High

THEN

Do the same while coming back with your AC on low and check the amount of fuel consumed.

Practical answers.

honmusa:

You already know the answer that increasing your AC level is like putting more load on your engine which is equivalent to more fuel consumption .

ogbiwa:
Pls I've been asking this question for sometime now. Does fuel consumption on AC vary with the various LO, MID HI AC levels or it consumes same amount once the AC is switched on regardless of the level. However i think my engine power changes as I either increase or reduce my AC. Auto gurus abeg food don done.

suco01:
Frm a car AC technician dat i asked, he told me d more u change d car AC frm low to medium to high and d engine change sounds, it consume more fuels dats y u see pple mostly stay on low to maintain a cool environment in d car to avoid more fuel consumption... To confirm hw true is dis, i disconnect my Uncle Hyundai H1 fuel hose frm tank into a 1litre fuel jerican and i put d mini bus ignition on and put d AC on low and i time it, i repeated d same 1litre fuel for medium and Hi. I dicovered the fuel consumed while d AC is on Hi vanish very fast than when in Low. Bt i dont knw 4 other cars oo. I rest ma case

Shikena:

Don't know how you did the hose to jerry can thing but please don't ever try that again jeez!

1886martino:

Engr how is it possible? Fuel hose inside... blah blah

martineverest:
Almost negligible.

The r.p.m removed from engine to power the compressor is almost negligible compared to that channeled to the Tyres.

The most important thing is: Use air con when driving at high speed and switch off the AC at lower speed

martineverest:
" evaporator Condenses": Never heard of that before

If you mean to ask if higher fan speed
with the AC will reduce your MPG, it
certainly will! The AC in your car (aside
from electric AC systems found in
hybrid and electric cars) works
differently from the electric systems in
buildings and houses. Automotive AC
systems use a compressor driven by
the engine through an electromagnetic
clutch. This allows the compressor to
be disengaged when not in use. When
you use the AC, the air is cooled by
passing over the evaporator which is
cooled by the work done by the
compressor. The evaporator gets
cooled to about 34°F but not much
lower to prevent ice accumulating.
When the evaporator reaches that
temperature, the compressor is
disconnected by the clutch. As air
continues to flow over the evaporator,
the evaporator takes the heat from the
air and its temperature increases.
When the evaporator reaches about
42°, the compressor clutch is engaged
and the evaporator is cooled back to
34°.
Increasing the airflow over the
evaporator causes it cool down more
slowly with the compressor engaged
and heat up more quickly with the
compressor disengaged. This results in
the compressor running for more time,
which takes more power from the
engine and results in fewer MPG than
when the airflow over the evaporator
is lower.
It takes work to cool air. The work is
ultimately done by the engine. More
work is required to cool more air.
Electric AC systems are governed by
the same rules.

https://www.quora.com/Does-the-increase-in-fan-speed-of-a-cars-AC-decrease-its-fuel-efficiency-Why-or-why-not

This means more fuel is used, not because the fan is using engine power to turn faster, but because the compressor ends up being engaged for longer and disengaged for far shorter periods during the use of the AC at higher fan speeds.