Will A/C blower speeds affect the Fuel Economy?

mobike008 · 20th February 2007, 11:30

Quote:

Originally Posted by rr_zen

Agreed. When you increase your blower speed beyond level 2 it affects FE and performance. This was also clarified by a Maruti service advisor for my Esteem. What I was told is that if you set the blower level to 2 the AC cools the front compartment alone housing the driver and the co-passenger seated on the left. Once the required temperature is attained, the AC is cut off and it is just the blower that is working. This reduces the strain on the engine and results in better FE and performance. On the contrary, if the blower level is set beyond 2, it goes ahead cooling the entire car and thereby the AC compressor is on for most of the time. This service advisor also gave me a pamphlet on fuel saving tips and the topic under discussion was one of them.

Firstly, switching on my AC there is "no" power slump

in my car, so effecting performance is ruled out.

However, i always use the outside air circulation for first 1 minute to let the hot air out and then switch it to the re-circulation mode for optimum coolness and in addition my knob is set at max cool level.

I guess, the FE slump is too tough to calculate if the blower speed is above 2 but, will try a tankful using that methodology and see if it makes any difference

akroy · 20th February 2007, 14:15

Maruti sent a guide about fuel efficiency after I bought my Alto...It mentioned in one of the points to keep the AC at 2, although you can put at 4 and cool it and then keep at 2 throughout (it also mentioned to keep the recirculation knob mostly)....and I tried it out successfully in one of my long drives...
Also I did feel there is little change in FE as well...
While my drive from Blr - Kol, I used 4 to cool the interiors (say in the fist 10min of starting the car) and then kept at 2 most of the time even in hot afternoons at Vijayawada, balasore etc...Although I drove above 100kmph at 2 most of the time, still the car returned a 18-19kmpl mileage in those stretches....
May be keeping the knob at 2 does use the AC optimally...

Abhi

rks · 22nd February 2007, 12:18

Quote:

Originally Posted by rr_zen

What you say is true regarding the cold air moving to the second compartment eventually but as far as I know there are'nt very many cars that have AC vents at the back except for the premium cars like Toyota, Lancer etc.

Usually air is blown out from the front in most cars. But as I pointed out in my earlier reply, there ought to be air vents towards the back or at least towards the middle of the car that will route the air back to the suction of the blower, in order to have good circulation. For example, see the Santro's "Air ventilation system" in the following link:

Welcome to Hyundai Motor :: Hyundai Santro

In addition to the air vents at the dash, the figure shows that there are air vents behind the front seats, towards the bottom. I have verified that these vents are present in my old Santro as well. Apparently the purpose of these vents is to improve the air circulation for rear passengers and will presumably return the air to the blower suction.

rr_zen · 22nd February 2007, 21:49

Quote:

Originally Posted by rks

In addition to the air vents at the dash, the figure shows that there are air vents behind the front seats, towards the bottom. I have verified that these vents are present in my old Santro as well. Apparently the purpose of these vents is to improve the air circulation for rear passengers and will presumably return the air to the blower suction.

I see what you mean. This is news to me about the rear vents in the Santro. Are there any other cars in the same range you know that sport this feature?

rks · 22nd February 2007, 22:21

Quote:

Originally Posted by rr_zen

I see what you mean. This is news to me about the rear vents in the Santro. Are there any other cars in the same range you know that sport this feature?

I don't think these are classified as rear A.C. vents, because they don't blow air. I am not aware of the situation in other cars in this range. I had always assumed that the recirculating air to the blower suction will be drawn from both the front and back sides of the car in order to have good circulation for all passengers.

Esteem_ist · 22nd February 2007, 22:39

Blower speed affects the fuel consumption margianally but not at a higher rate, when you switch on the A/C it takes not less than 5hp to run the compressor and provided electricity to blower fans, and you feel the vehicle slowing down and you increase the throttle which will in turn increases the fuel consumption, so you might find the reduction just around 1KMPL depending on your increase in the throttle.

Esteem_ist · 22nd February 2007, 23:18

Just Blower Speed Does Not Affect Fuel Consumption

rks · 23rd February 2007, 12:41

Quote:

Originally Posted by rks

For example, see the Santro's "Air ventilation system" in the following link:

Welcome to Hyundai Motor :: Hyundai Santro

In addition to the air vents at the dash, the figure shows that there are air vents behind the front seats, towards the bottom. I have verified that these vents are present in my old Santro as well.

Correction. I have not been able to identify any such vents in my old Santro. They must be present in the Xing, if the indicated figure is accurate.

bayuin2004 · 23rd February 2007, 21:40

i dont think the blower speeds affect the FE of a car,but it will surelyu take power from the battery..

spatafarose · 1st April 2007, 21:06

FE and blower speed does not have any connections.When you switch on AC, the compressor works and the blower just works to circulate the cold air.FE wont increase in lower fan speeds.

arunkumar_rec · 17th December 2007, 09:09

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 · 17th December 2007, 11:41

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

arunkumar_rec · 17th December 2007, 11:49

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 · 17th December 2007, 12:56

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 · 17th December 2007, 19:51

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.

20th February 2007, 14:15	#17
akroy Senior - BHPian Join Date: Feb 2006 Location: San Francisco, CA, USA Posts: 2,423 Thanked: 85 Times View My Garage	Maruti sent a guide about fuel efficiency after I bought my Alto...It mentioned in one of the points to keep the AC at 2, although you can put at 4 and cool it and then keep at 2 throughout (it also mentioned to keep the recirculation knob mostly)....and I tried it out successfully in one of my long drives... Also I did feel there is little change in FE as well... While my drive from Blr - Kol, I used 4 to cool the interiors (say in the fist 10min of starting the car) and then kept at 2 most of the time even in hot afternoons at Vijayawada, balasore etc...Although I drove above 100kmph at 2 most of the time, still the car returned a 18-19kmpl mileage in those stretches.... May be keeping the knob at 2 does use the AC optimally... Abhi
	() Thanks

22nd February 2007, 22:39	#21
Esteem_ist Newbie Join Date: Feb 2007 Location: HYDERABAD Posts: 2 Thanked: Once	Blower speed affects the fuel consumption margianally but not at a higher rate, when you switch on the A/C it takes not less than 5hp to run the compressor and provided electricity to blower fans, and you feel the vehicle slowing down and you increase the throttle which will in turn increases the fuel consumption, so you might find the reduction just around 1KMPL depending on your increase in the throttle.
	(1) Thanks

22nd February 2007, 23:18	#22
Esteem_ist Newbie Join Date: Feb 2007 Location: HYDERABAD Posts: 2 Thanked: Once	Just Blower Speed Does Not Affect Fuel Consumption
	() Thanks

23rd February 2007, 21:40	#24
bayuin2004 BHPian Join Date: Sep 2006 Location: hyderabad Posts: 30 Thanked: 0 Times	i dont think the blower speeds affect the FE of a car,but it will surelyu take power from the battery..
	() Thanks

1st April 2007, 21:06	#25
spatafarose BHPian Join Date: Mar 2007 Location: Cochin Posts: 32 Thanked: 0 Times	FE and blower speed does not have any connections.When you switch on AC, the compressor works and the blower just works to circulate the cold air.FE wont increase in lower fan speeds.
	() Thanks

17th December 2007, 09:09	#26
arunkumar_rec BHPian Join Date: Aug 2007 Location: Chennai Posts: 106 Thanked: Once	Will A/C blower speeds affect the Fuel Economy? 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
	() Thanks

17th December 2007, 11:41	#27
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,215 Thanked: 15,907 Times	Yes when the blower speed is high, AC compressor will be ON for more time and in turn reduce FE.
	(1) Thanks

17th December 2007, 11:49	#28
arunkumar_rec BHPian Join Date: Aug 2007 Location: Chennai Posts: 106 Thanked: Once	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
	() Thanks

17th December 2007, 12:56	#29
kiranpashtakar BHPian Join Date: Aug 2005 Location: Bangalore/Hyderabad Posts: 257 Thanked: 7 Times	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. Last edited by kiranpashtakar : 17th December 2007 at 12:58.
	(1) Thanks

17th December 2007, 19:51	#30
PAVAN KADAM BANNED Join Date: Jan 2007 Location: NAMMA BENGALURU Posts: 5,602 Thanked: 2,549 Times	Will A/c Blower Speed Affect Fe 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.
	() Thanks