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Evening all,

Given the cold weather we are experiencing recently. I have noticed that cold air blows in the footwell area in both the passenger and drivers side. Even with the AC turned up at a high temperature, I can still feel this cold breeze around my foot. Have tried all the different modes on the AC, but no luck.
Half and hour later and my knees are cold to the bone. 
Does the IS not have a good insulation around the footwell area?

Had this same issue with my old IS 250. 

Any one have similar issues. 
 

Thanks

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Turning it off and using just the heater causes the car to fog up inside. 
The A/C does blow hot air, but there is this cold breeze that comes around the foot area.

 

 


 


 

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Setting it to Auto makes the fan to turn on full blast, so normally use own speed and air direction. the air direction I set is normally internal air circulation.

But this should not cause cold air to creep in. 

I feel the air seems to come from the foot pedals area. 

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2 hours ago, Slucky said:

Setting it to Auto makes the fan to turn on full blast,

That doesn't sound right. Does it still do this when the cabin has warmed up? Mine is pretty quiet most of the time. I keep it on auto most of the time and around 21 or 22 degrees. There's a big contrast in fan speed if I turn on the windscreen demister, which does set the fan to full speed.

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Not having it on Auto can lead to cold areas in the car. I only control mine with temperature and I keep it on Auto all the time unless trying to defrost a windscreen first thing in the morning. As soon as it’s clear I select Auto again. If the temperature in the car is massively different to the temperature set on the climate control then the fan will be working overtime to bring the cabin to the set temperature. Once the cabin is at the set temperature the fan speed should drop back down again. Auto ensures that the climate control system sets fan speed and air flow direction to optimal levels to keep the cabin at the set temperature. Unless there is a fault.

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9 hours ago, Slucky said:

Setting it to Auto makes the fan to turn on full blast,

That's probably because it is then working hard to get the cabin temperature to whatever it's set at.

Quote

the air direction I set is normally internal air circulation

Why?

You should have it set to bring in fresh air from outside, which the system will then condition and mix with hot/cold to achieve the set temperature. That's the whole idea behind climate control instead of just air conditioning - you set whatever cabin temp you want and the system will condition, mix and do whatever it has to to keep that temp constant.

Having the system constantly set to recirculate internal air is both unhealthy and will cause condensation problems.

If it is set and used properly you'll also notice something else and that is that when starting from cold the system will probably not blow any air out for a couple of minutes. When it does start, it'll be coming from footwell vents because hot air rises and the quickest way to get the cabin up to temp is to blow it from below and let it rise. On a hot summer day you'll notice the reverse happen as cold air is blown from the dash and face vents.

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25 minutes ago, Herbie said:

when starting from cold the system will probably not blow any air out for a couple of minutes

I was going to say that but you beat me to it!

The system is waiting for the engine coolant temperature to reach a useful level that can actually heat the cabin. So paradoxically it can mean that on a really cold day when the engine is at zero degrees or lower the fan won't start up for a longer period (even though you need the heat sooner!) than on a mild day when the engine starts at 10 or 15 degrees. I'm not sure how long this might be but I have the impression that it could be as much as five minutes on a cold day. At least it's not a diesel where you might have to wait 10 minutes for any heat to start to come through. While you're waiting the heated seats can help.

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Thank you all for enlightening me on this subject. 

It makes sense now, so I was using my A/C the wrong method. 

My wife never liked the A/C as she expected the warm air to kick in instantly during the cold season, so we would battel it out on the controls for the heating.

So Auto all the way.

Cheers

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Climate control does exactly what it says on the tin. It controls the climate inside the car. Manufacturers spend many many millions trying to perfect their systems and the results will be far better than a driver can achieve by manually setting the various controls. Keep it in Auto and if you feel cold turn the temperature up and if you feel hot turn it down.

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Thanks Paul, much appreciated with the info. 
As I have an IS 300h hybrid. Does the A/C use the Battery or the engine to power the unit. Having heard that AC usage decreases the mpg. 
 

Thanks

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18 minutes ago, Slucky said:

Thanks Paul, much appreciated with the info. 
As I have an IS 300h hybrid. Does the A/C use the battery or the engine to power the unit. Having heard that AC usage decreases the mpg. 
 

Thanks

It makes very little difference to the MPG, such a small difference that it's really and truly not worth worrying about. Like we've said above, climate control is designed to be active all the time so just let it do its job.

To answer your question, the aircon compressor is driven from the hybrid system by a 500V 3-phase variable frequency electric motor.

Our cars don't have starter motors, alternators, or anything that would normally be belt-driven by the engine because the engine doesn't run continuously - it is stopped and started by the hybrid system as it sees fit.

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There are also some settings in the vehicle settings for climate. I turn off efficient air and I switch off one other setting which I can’t remember off the top of my head. They are both aimed at limiting use of the AC compressor. In all of my recent Lexus vehicles (6) I’ve switched these off because I found that they cause poor control of the temperature inside the cabin. Within the climate control settings I also select Normal and never Eco because this prevents a similar effect. It’s a negligible saving selecting all these silly settings and I place comfort inside the cabin above saving say 0.5 mpg.

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