Hot Air Conditioning

[Emma9x]

I have a Yaris TR 2008. On cold mornings the car steams up and takes 10+mins to desteam. i have tried putting the blowers onto the windscreen, turning it onto hot and adding the air con (air con does not help!!). When i asked Toyota they said the air con is to cool not to heat.. this is not the case with any of my friends or families cars who can use it to make the air hot quickly. Does any one else have this problem or is it just mine??

Please help.

Thank you

Em

[Penguin1958]

I have a Yaris TR 2008. On cold mornings the car steams up and takes 10+mins to desteam

My Yaris seems to take longer than other cars to demist, it doesn't take 10+ minutes though. Make sure you have the air intake set to fresh and not recycling.

[Blue84]

I have a Yaris TR 2008. On cold mornings the car steams up and takes 10+mins to desteam. i have tried putting the blowers onto the windscreen, turning it onto hot and adding the air con (air con does not help!!). When i asked Toyota they said the air con is to cool not to heat.. this is not the case with any of my friends or families cars who can use it to make the air hot quickly. Does any one else have this problem or is it just mine??

Please help.

Thank you

Em

I use mine on heat to get the windscreen clear when theres a frost & I am in a rush in the morning, it's never done mine any problems.

There arent any signs of leaks in your car are there? I know I get in my car when I've got soaking wet in the rain it steams up all round, so there might be excess moisture getting in somewhere?

BTW it's just a suggestion before anyone comments!

[Rayburn]

I have a Yaris TR 2008. On cold mornings the car steams up and takes 10+mins to desteam. i have tried putting the blowers onto the windscreen, turning it onto hot and adding the air con (air con does not help!!). When i asked Toyota they said the air con is to cool not to heat.. this is not the case with any of my friends or families cars who can use it to make the air hot quickly. Does any one else have this problem or is it just mine??

Please help.

Thank you

Try setting the Temp control to Cold. Aircon On. Dash vent set to Fresh air.

With the A/C on it does aid a little in De- misting.......Not a lot

R

[moonstone mart]

I have a Yaris TR 2008. On cold mornings the car steams up and takes 10+mins to desteam. i have tried putting the blowers onto the windscreen, turning it onto hot and adding the air con (air con does not help!!). When i asked Toyota they said the air con is to cool not to heat.. this is not the case with any of my friends or families cars who can use it to make the air hot quickly. Does any one else have this problem or is it just mine??

Please help.

Thank you

Em

Hi Emma,

As said above set to cold / AC on / recirc off. This is best way to demist the screen. AC should definately help as it dries the air inside the car.

Also make sure none of your carpets inside the car are wet and that windows are fully closed as this can make the car steam up.

Your point you made about friends using AC to heat car up quicker cannot happen as the AC system only cools the air faster - it cannot make the car heat up quicker as this is done by the engine coolant. You can indeed run the A/C on warm when the engine is warmed up but AC certainly doesnt heat the air.

Mart.

[Chris81]

I'm glad I've read this thread as I always wondered. When the salesman was giving me the patter about air con he did say it helps de-steam the car. Like the OP I'd always thought you had to have the heater to hot and turn the AC on but it made no difference. Now I know to leave it on cold.

Out of interest, what effect does having the heater on hot and AC on actually do? Does it serve any purpose?

[Parts-King]

Out of interest, what effect does having the heater on hot and AC on actually do? Does it serve any purpose?

Yes it does, it stops you freezing your :censor: off

Seriously, the A/C system certainly provides cold air in the summer, we all know that, but it also de-humidifies the air, removing moisture and clearing your screen faster, but you can and should use it in the winter as well, as Mart says, it wont speed up the heating process, but it will remove the heavy moist air from the car even before it starts to warm up

Kingo

[Richard Davies]

Using the A/C in winter also should keep the seals in good nick as they can perish if the unit is unused for a long time.

[rallybunny]

Probably a really silly suggestion, but I was really worried that my car was getting really steamed up and taking ages to clear. It was only when I realised a few days later that I'd accidentally left the blowers on recirc rather than fresh air, so all the moisture was just staying in the car.

[Richard Davies]

Probably a really silly suggestion, but I was really worried that my car was getting really steamed up and taking ages to clear. It was only when I realised a few days later that I'd accidentally left the blowers on recirc rather than fresh air, so all the moisture was just staying in the car.

I did this about a year ago & couldn't understand why the windows seemed to be misting up even more as the car warmed up.

[sue8i8]

Hi

I've been having problems trying de-steaming my Toyota Yaris TS 2002, I also find that using the air con helps, or opening a lil gap in the window, the only downside its freezing cold!!!

As soon as I get in the car I put the heating on (no steam on any windows), then say about 5 mins into my journey the side windows in the back are completely steamed up, making it impossible to check my blind spot! Then the front side windows start steaming up on the edges, and thats when I need to put on the air con or open the windows...

I've put those moisture bags in the car, and they have been soaked, but it doesn't help at all, because they need drying out.

Is this a common problem for all Yaris or do I have a seal problem? If so, does anyone know how much it would cost to solve?

Thanks~

[Richard Davies]

Try reading the posts above yours, I had similar trouble because I left the heater on recirculate instead of setting it to draw in air from outside.

[Mat-O]

I find that having AC on and the air on hot helps a lot, especially if you have a full car and it's really cold outside.

[oldun]

I'm glad I've read this thread as I always wondered. When the salesman was giving me the patter about air con he did say it helps de-steam the car. Like the OP I'd always thought you had to have the heater to hot and turn the AC on but it made no difference. Now I know to leave it on cold.

Out of interest, what effect does having the heater on hot and AC on actually do? Does it serve any purpose?

There are effectively two stages to air conditioning.

The first is to cool the air down to a temperature below the temperature at which the air born moisture will condense (the dew point temperature). If kept at that temperature for sufficient time the air will leave much drier but at a very cold temperature.

The second phase of the air conditioning is to heat the back up to the required temperature. The temperature of the delivered air may be higher or lower than the original air temperature - it' s entirely up to you.

The heating of the air takes place after the air has left the cooling unit so it should have no effect upon the cooler.

If the air is very cold and near to the dew point then the sir conditioner cannot have any significant effect on the relative humidity of the air.

Heating up air cannot make it any drier, the absolute humidity will not be changed. However when the air temperature rises the ability of the air to absorb more moisture is increased. This means that while the actual amount of moisture in the air (X) remains the same the maximum amount that can be absorbed (Y) is increased so the ratio of X/Y decreases. The ratio X/Y is known as the relative humidity (rh)and is usually expressed as a percentage. 0% rh means that the air is totally dry. 100% rh means that the air is holding the maximum amount of moisture.

The body is sensitive to the relative humidity and not the absolute humidity so warmer air seems dryer.

The hotter and drier the air hitting the windscreen the better the demisting - air con on and full heat. Unfortunately when you first start off there is no heat to make use of.

Car salesmen often know very little about cars in general and often have a limited knowledge of the general information relating to the cars they are selling. They generally have no real knowledge of the detailed working of car (why should they!) so you must take lectures on the workings of turbo chargers, anti-lock brakes and air conditioning (etc) with a large pinch of salt.

[Red Yaris 54]

I'm glad I've read this thread as I always wondered. When the salesman was giving me the patter about air con he did say it helps de-steam the car. Like the OP I'd always thought you had to have the heater to hot and turn the AC on but it made no difference. Now I know to leave it on cold.

Out of interest, what effect does having the heater on hot and AC on actually do? Does it serve any purpose?

There are effectively two stages to air conditioning.

The first is to cool the air down to a temperature below the temperature at which the air born moisture will condense (the dew point temperature). If kept at that temperature for sufficient time the air will leave much drier but at a very cold temperature.

The second phase of the air conditioning is to heat the back up to the required temperature. The temperature of the delivered air may be higher or lower than the original air temperature - it' s entirely up to you.

The heating of the air takes place after the air has left the cooling unit so it should have no effect upon the cooler.

If the air is very cold and near to the dew point then the sir conditioner cannot have any significant effect on the relative humidity of the air.

Heating up air cannot make it any drier, the absolute humidity will not be changed. However when the air temperature rises the ability of the air to absorb more moisture is increased. This means that while the actual amount of moisture in the air (X) remains the same the maximum amount that can be absorbed (Y) is increased so the ratio of X/Y decreases. The ratio X/Y is known as the relative humidity (rh)and is usually expressed as a percentage. 0% rh means that the air is totally dry. 100% rh means that the air is holding the maximum amount of moisture.

The body is sensitive to the relative humidity and not the absolute humidity so warmer air seems dryer.

The hotter and drier the air hitting the windscreen the better the demisting - air con on and full heat. Unfortunately when you first start off there is no heat to make use of.

Car salesmen often know very little about cars in general and often have a limited knowledge of the general information relating to the cars they are selling. They generally have no real knowledge of the detailed working of car (why should they!) so you must take lectures on the workings of turbo chargers, anti-lock brakes and air conditioning (etc) with a large pinch of salt.

The salesman at my local Toyota dealer is very clued up on the workings of the cars that he sells

Just make sure that large pinch of salt does not corrode your car ;)

[oldun]

I'm glad I've read this thread as I always wondered. When the salesman was giving me the patter about air con he did say it helps de-steam the car. Like the OP I'd always thought you had to have the heater to hot and turn the AC on but it made no difference. Now I know to leave it on cold.

Out of interest, what effect does having the heater on hot and AC on actually do? Does it serve any purpose?

There are effectively two stages to air conditioning.

The first is to cool the air down to a temperature below the temperature at which the air born moisture will condense (the dew point temperature). If kept at that temperature for sufficient time the air will leave much drier but at a very cold temperature.

The second phase of the air conditioning is to heat the back up to the required temperature. The temperature of the delivered air may be higher or lower than the original air temperature - it' s entirely up to you.

The heating of the air takes place after the air has left the cooling unit so it should have no effect upon the cooler.

If the air is very cold and near to the dew point then the sir conditioner cannot have any significant effect on the relative humidity of the air.

Heating up air cannot make it any drier, the absolute humidity will not be changed. However when the air temperature rises the ability of the air to absorb more moisture is increased. This means that while the actual amount of moisture in the air (X) remains the same the maximum amount that can be absorbed (Y) is increased so the ratio of X/Y decreases. The ratio X/Y is known as the relative humidity (rh)and is usually expressed as a percentage. 0% rh means that the air is totally dry. 100% rh means that the air is holding the maximum amount of moisture.

The body is sensitive to the relative humidity and not the absolute humidity so warmer air seems dryer.

The hotter and drier the air hitting the windscreen the better the demisting - air con on and full heat. Unfortunately when you first start off there is no heat to make use of.

Car salesmen often know very little about cars in general and often have a limited knowledge of the general information relating to the cars they are selling. They generally have no real knowledge of the detailed working of car (why should they!) so you must take lectures on the workings of turbo chargers, anti-lock brakes and air conditioning (etc) with a large pinch of salt.

The salesman at my local Toyota dealer is very clued up on the workings of the cars that he sells

Just make sure that large pinch of salt does not corrode your car ;)

Many salesmen will know a lot about the spec of the car, performance, cost, options and other things like that which represents almost all the information needed by people purchasing cars but I was trying to point out that they will, in general, not know much about (and do not need to know much about) the inner workings of the engine, engine management system, air-con, anti-lock system, turbocharger etc system etc so anything they say on these matters are usually not very accurate. To get this sort of information you need to talk to the experienced service engineers etc.

I am not belittling salesmen just pointing out they are not usually the technical experts they sometime profess to be.

[cabcurtains]

In my experience the best salesman sell the most cars thus they are salesman 1st! Technical knowledge isnt needed if your shifting loads of metal, it kind of explains why the best i have worked with used to sell windows or kerby cleaners!

[Cyker]

I have a Yaris TR 2008. On cold mornings the car steams up and takes 10+mins to desteam. i have tried putting the blowers onto the windscreen, turning it onto hot and adding the air con (air con does not help!!). When i asked Toyota they said the air con is to cool not to heat.. this is not the case with any of my friends or families cars who can use it to make the air hot quickly. Does any one else have this problem or is it just mine??

Please help.

Thank you

Em

A very late FYI; The AC units in your friend's cars are probably actually Climate Controlled; With these you just set the temperature to 25C or something and the fans will quickly start blowing out hot air until the temp in the cabin reaches 25C :)

Standard A/C just cools the air, but it can help a little with de-misting.

The Yaris is pretty awful for misting up (Like the Fiesta I had beforeit, it mists up at the drop of a hat!), but IMHO the best solution is to get one of those anti-misting cloths or chemicals and just wipe/spray it onto the windows that mist up the worst; It helps a lot!

[Raeman]

I had a similar problem with my Honda Accord. Then i changed the pollen (air-con) filter and hey presto...clear windows, faster de-misting, colder air-con and much hotter heaters!!

Best £17.25 i ever spent!! :D