Will A/C blower speeds affect the Fuel Economy?

[arunkumar_rec]

I was told by the Hyundai Dealer that once the A/C button in switched on(GETZ), the different blower speeds won't matter with respect to the FE.

Whether the blower is at the lowest speed or highest speed, the mileage will be affected by the same amount. This is the claim of the dealer.

But when I had a chance to go through the Service manual of my car, it advises to reduce the blower speed once the desired cooling has been achieved which will save the fuel.
Is the service manual right or the dealer right?. I am confused.
Experts, please help.
Thanks.
Arun

[Jaggu]

Yes when the blower speed is high, AC compressor will be ON for more time and in turn reduce FE.

[arunkumar_rec]

Jaggu, so the service manual is right.
That sounds great. I don't like the blower even at speed 3. I am more comfortable in 1 or 2 once the desired cooling is achieved.
Thanks.
Arun

[kiranpashtakar]

Just to help you understand this better,

When the AC is on the compressor puts a certain amount of load on the engine. Which is used not for the vehicular motion but for cooling and hence the mileage the car returns decreases.

What happens when the Blower is set to high is there is more cold air passing through the compressor, which makes it work for a longer time.
And hence the mileage decreases.

Let me add another dimension to this, what if your cars is insulated 100% then you will find that the car gets colder faster and the AC is switched off faster and hence the mileage the car returns will be higher

In reality it depends on when you are using the AC, when the outside temperature is hot and then high blower speed will decrease Mileage.
If the outside temperature is Cold the mileage returned will be higher.


And the blower is battery operated and hence just running the blower with out the AC will not have any effect on the mileage.

[PAVAN KADAM]

Definetly,

Using Blower Speed At Low Initially Will Reduce F E Reason Being Once You Put On Your A.c Blower At Low Speed The Cooling Of The Car Interior Takes Lot Of Time And Hence The Compressor Will Run For A Longer Time Affecting Fe.

Using Blower At High Speed Initially Will Cool The Interiors Faster And Its Wise To Switch To A Lower Speed Later.

Kindly Refer Times Auto Article For Nov 15th 2007.

There's A Complete Writeup On How To Use A.c In Your Car.

[arunkumar_rec]

Thanks for all your inputs. I will atleast set the dealer right so that they wont misguide their customers regarding the A/C blower speeds.

Arun

[dvswift]

As it was pointed out, Blower is an electrical load which is going to run on the battery.
The moment you are discharging the battery, the Alternator kicks in. The more you are discharging the battery, the longer the Alternator would run and hence lower the FE. Blower Speeds do matter.

[saurabh159]

Hi,
Does the same logic of A/c blower speed applies also in the condition when only heater is on ?
Whats the effect of A/c verses Heater on the FE ?

[arunkumar_rec]

I feel using the heater should not affect the FE as the heat is derived from the engine heat which anyway goes as a waste. Please correct me if I am wrong.

[ragzv]

Yes the car heater very much uses engine heat (in most cars) , thus when a engine is cold it takes some time for the hot air to come.

Few cars also come with coil based heaters. I remember my cousin who had fitted an after-market coil based heater in his Maruti 800 as in Amritsar the temp reaches 0 degrees or below and by the time the engine heated up they were already frozen.

[murugaveln]

The manual also says to set the airflow knob to let outside air flow instead of recycling air when the a/c is on. Does this also have any efffect on the FE?

Thanks.

[arunkumar_rec]

Yes. FE will be affected. This has been discussed before. The A/C unit will consume more fuel to cool the hot outside air when the A/C is kep it in fresh air mode. If the A/C is kept in recirculation mode, load on the compressor is less as the inside air is already cool. So better FE.

[Maverick1977]

Originally Posted by dvswift

As it was pointed out, Blower is an electrical load which is going to run on the battery.
The moment you are discharging the battery, the Alternator kicks in. The more you are discharging the battery, the longer the Alternator would run and hence lower the FE. Blower Speeds do matter.

DVSWIFT ---> I beg to differ that using just the blower will have an effect on the FE. In such a case the FE will be reduced if you are playing the ICE. Of course it depends on the type of ICE, but a regular HU & 4 speakers would not make such a great impact on the battery consumption.