Air con - which is better?

[Pskvin]

after so many year of driving, i still not sure on this:

which is the better way to switch on the air con for better car performance + better fc + better interior comfort(cooling)?

thanks.

[BoneStock]

The FC for my ride is ok but I usually adjust the aircon to cater to the comfort of the passengers rather than FC.

 

When I am alone, usually switch fan speed to 1 and temp to 23~25deg. this is pretty comfy for S'pore climate. When there are more than one passengers, me will turn up the fan speed to 2 or 3 depending on outside temp.

 

Aircon setting also depends on what type of car. The aircon for my current Nissan is quite powerful so usually fan speed 1 suffice. For my previous Honda ride, I found myself turning to fan speed 2 and almost coldest temp most of the time even when I was alone in the car.

[macrosszero]

When you're driving alone, close the other unused vents so that you can make do with a lower fan setting and not need to set the temperature that low.

 

You only need to cool yourself, not the whole car cabin, even though that contributes to the overall comfort. Direct air blowing at you helps to take away heat and moisture already.

[Watwheels]

As long as u on the air-con it is putting load on your engine.

 

That's why nowadays car air-con come with automatic sensors to ajust accordingly to outside temp. It will cool sufficiently and save energy or FC.

[Friendstar]

nissan's air con is indeed powerful!

[Friendstar]

regarding TS's question... if u lower the temperature... the engine will be heavily taxed becos it has to work harder to bring temperature down.

 

meaning to say, if u wan good FC and errr to an insignificant extent engine performance,

turn up the fan speed instead of lowering the aircon temperature.

[Watwheels]

like that u'll still sweat.

[Adawang]

At highest fan speed , the coil will not be as cold as u want it to be.

if u want it cold , set near to lowest and adjust fan speed accordingly.

setting at max cold might freeze the coil n block the air flow over the coil

[Pskvin]

i always wanted to do the same, but most of the time i forgot.

 

When you're driving alone, close the other unused vents so that you can make do with a lower fan setting and not need to set the temperature that low.

 

You only need to cool yourself, not the whole car cabin, even though that contributes to the overall comfort. Direct air blowing at you helps to take away heat and moisture already.

[Pskvin]

i make a mistake here, i should ask

 

a. low temp + low fan

b. higher temp + high fan

 

after so many year of driving, i still not sure on this:

which is the better way to switch on the air con for better car performance + better fc + better interior comfort(cooling)?

thanks.

[Russ]

OK here goes.

 

Air conditioners are at the most efficient (in terms of amount of cooling per unit power consumed) when the fan is at maximum as the increase in air flow over the cool condensor unit will improve heat transfer from the air to the coolant inside. Also you have greater air circulation and are less likely to have cold and hot spots in the cabin. However, there is a point beyond which any additional air throughput does not improve heat transfer and the increase in fan speed actually reduces efficiency as it starts to consume more power.

 

Temperature setting - Singaporeans have NO IDEA how thermostats work. Basically, car air con compressors have 2 settings - ON and OFF. When the desired temperature is reached, the compressor cuts off and then cuts in again when the temperature increases 1-2 deg above the set temperature. So, if it is 35 deg outside with a hot sun and it is 30 deg inside your car, turning the temp dial from 25 deg to 18 deg with have NOT turn the air con any colder.

 

So:

1. If your car is not hot (say in a MSCP), then turn on MED fan and then to MED or LOW when the car cools a bit.

 

2. If your car is HOT, turn on the FAN as HIGH as you can bear the noise until the car is cooler, then leave it at MED - if it is really hot outside, turning it to LOW should leave some parts of the car a bit warm.

 

3. Set the temperature at 24 or 25 degC. It is very highly unlikely that your car air con has enough capacity to cool it to 18 deg when it is 35 deg outside. At night, you might get to 18 deg as there is no sun to heat the car up, but then you end up burning a lot more fuel getting to that temp.

 

The other thing is that HOW COMFY you feel depends on TEMPERATURE AND HUMIDITY. I bet you that if I put you in a room at 28 deg and 20% humidity, you will swear it feels cooler than a room that is at 27 deg but 80% humidity - trust me, I have about 10 thermometers and a few hygrometers all over my apartment.

[Icekitten]

Do you mean

 

a. low temp + high fan

b. higher temp + low fan

 

instead?

[Friendstar]

Temperature setting - Singaporeans have NO IDEA how thermostats work. Basically, car air con compressors have 2 settings - ON and OFF. When the desired temperature is reached, the compressor cuts off and then cuts in again when the temperature increases 1-2 deg above the set temperature. So, if it is 35 deg outside with a hot sun and it is 30 deg inside your car, turning the temp dial from 25 deg to 18 deg with have NOT turn the air con any colder.

 

Yes it will not turn the air con any colder, but since u'r making the compressor churn for longer periods, inevitably arent u also making the cabin cooler?

[Dumb]

after so many year of driving, i still not sure on this:

which is the better way to switch on the air con for better car performance + better fc + better interior comfort(cooling)?

thanks.

 

It doesn't matter which ever way as long as you are satisfied that it's cold enough for you.

 

I think turning the fan higher will only cool the cabin faster and that's all. If you want colder air, you need to turn the temperature down.

 

Normally, I set my temp at 26 and when I auto on the air con, the fan speed can be between position 1 and 4 depending on the cabin's temperature. The fan speed will then auto drop to 1 when the desired temp is reached.

Edited January 6, 2007 by Dumb

[Russ]

It depends if the air con can achieve the originally set temp.

 

If, at full blast, with maximum passengers on a 35 deg day and hot sun, the air con can only manage to get it down to 28 degrees, it makes no difference if you set it at 27 degrees or 5 degrees!!

 

My point is that most people here think that lowering the temperature setting increases the aircon power!! It does not...

[Kklee]

Temperature setting - Singaporeans have NO IDEA how thermostats work. Basically, car air con compressors have 2 settings - ON and OFF. When the desired temperature is reached, the compressor cuts off and then cuts in again when the temperature increases 1-2 deg above the set temperature. So, if it is 35 deg outside with a hot sun and it is 30 deg inside your car, turning the temp dial from 25 deg to 18 deg with have NOT turn the air con any colder.

 

Some car uses variable displacement compressors which do not have thermostats.

[Russ]

That's interesting - which ones?

 

Whatever the case, I still hold my case that if the compressor is already at full blast and the set temperature is significantly lower than the temperature in the cabin, lowering it further will not make the car any cooler.

Edited January 7, 2007 by Russ

[Kklee]

I know for sure ... Chevrolet Optra. Usually conti design but off the internet, seems Toyota Camry. Toyota Estima and Hyundai Accent.

Edited January 8, 2007 by Kklee