Air Con And Fan

[square1]

Can anyone advise on the following?

In the Aygo, does having the air con on at the same time as the fan make any difference to demisting? Also, does having the fan on without the air con increase fuel consumption? Basically, I'm aiming for good demisting performance with minimal impact on my mpg.

[FROSTYBALLS]

You need the fan on when using air conditioning to assist the movement of cold or warm air. We've had 11 cars with air conditioning, and find the best way to demist is to use the air con, have the flow of air directed to the windscreen, heater temperature control set to somewhere in the red (warm) and the fan on. Once effective demisting has occured, turn the air con off. Far faster than trying to demist just using air flow.

The fan should have negligible effect of fuel consumption.

Air con does have an effect of fuel consumption as the engine is having to provide additional power for the condenser.

[square1]

Hi Frosty, thanks for the advice. It sounds like I've been doing it right, although I do find that during journeys I have to switch the air con/fan on for about a minute, the windows demist and then later on I have to repeat this. I hope I'm not wearing it out by switching them on and off so often but I do it to reduce fuel consumption.

[FROSTYBALLS]

That sounds OK. Sometimes if the outside environment is especially wet, and/or people are getting in and out with wet clothing on, cars will need demisting at intervals. You wouldn't need the air con on all the time, but keeping the fan on, even at one of the lower settings, will help keep the windows clear.

Air conditioning does need to be used all year round to ensure the seals, etc keep lubricated. So we tend to use the air con at least once every couple of weeks in the winter - in practice, usually we use it more often than this.

[daveyjp]

Once you turn aircon off moisture which was being dried out by the condensor begins to return causing condensation on the windows. My way of operating aircon is to turn it on when I get a car and never turn it off.

There is an effect on mpg, but modern systems are now far more effective and cycle their operation so they aren't drawing power 100% of the time - you can hear the aircon cycling on the Aygo.

[dwilson]

The Aygo gives many mpg and this is a good feature. The Aygo produces more condensation than any other car I have driven because I assume it is so small and this is not a good feature. The fan will use some energy but is not worth worrying about. The air conditioning will use more energy but probably not worth worrying about in my opinion. The air conditioning conditions the air and reduces the humidity so well worth using in cold weather. I rarely turn the air conditioning off - the only time would be when I have the windows open. As a result I may spend slightly more on fuel but never have problems with the seals etc on the air con: so no nasty surprise bill there. At the end of the day it is down to personal preference but I would say the Aygo needs the air con running more than the average car. I don't think I have any leaks but it sure does yield a lot of condense.

David

[Raistlin]

I have to agree with David, I use my air con all year round with no noticeable effects on economy and defrosting or removing condensation is so much quicker with it

[square1]

When the a/c button is pressed in but the fan is not on, the green light on the button doesn't shine. In this case, is the air con still on and working or does it require the fan to be on at least no 1?

[FROSTYBALLS]

I would say that it needs to be fan assisted.

[Raistlin]

When the a/c button is pressed in but the fan is not on, the green light on the button doesn't shine. In this case, is the air con still on and working or does it require the fan to be on at least no 1?

No it only works with the fan on, although on setting 1 it is not noisy it's only when you set it to warp 5 that you get a gale :)

[Cyker]

Yup, the AC will NOT switch on unless the fan is running. My Yaris is like that too.

You may have to cycle the air-con now and then to demist the windows and keep them demisted but, if you do just leave it on, the Aygo has a neat feature where it automatically disengages the aircon when the engine is loaded and then turns it back on when it isn't.

Apparently the aircon uses a magnetic clutch so, in theory, turning it on and off repeatedly shouldn't wear anything out.

Once the engine is good and hot tho', often you can just turn the AC off and use hotter air to demist the windows (That's how I did it before I had a car with AC!)
Only downside with that is it does increase the humidity in the car which may lead to increased misting later etc.