Condensation in the cabin in cold weather

[Ian Key]

Do you think that if the A/C and heating runs at fan speed 6 for 43 minutes and fails to defog the window in that time, that blowing on the glass with that button will help? It won't. It'll just hum loudly, maybe defog a little more, but that's about it...

You can try humming. It might put you in a better mood. You could also turn the temperature up to high.

 

[Martinonline]

@baader, the demist button boosts the fan, sets recirculation to auto (primarily internal), prioritises the windscreen, turns on the AC and sets a suitable temperature. These are things MG think you need to demist the car. If you set you HVAC to settings other than these you should not expect the demist to work properly.

If your AC is not working properly then the condensation will not go, perhaps it needs to be checked. If you are sucking in outside air you are not helping.

I do not know what happens if you select any ECO mode but probably not good for your problem.

Personally, I have not had any issues in cold, wet, snowy and rainy glorious Yorkshire.

 

[NickHeynes]

@baader, the demist button boosts the fan, sets recirculation to auto (primarily internal), prioritises the windscreen, turns on the AC and sets a suitable temperature. These are things MG think you need to demist the car. If you set you HVAC to settings other than these you should not expect the demist to work properly.

If your AC is not working properly then the condensation will not go, perhaps it needs to be checked. If you are sucking in outside air you are not helping.

I do not know what happens if you select any ECO mode but probably not good for your problem.

Personally, I have not had any issues in cold, wet, snowy and rainy glorious Yorkshire.

I agree, except about sucking in outside air. You need to suck in outside air after a while . I've not had any problems at all living in Essex which tends to be more rainy.

I was in the Motor trade for 15 or so years and we were always taught :
When cold/damp : When first setting off . Air set to RECIRC . A/c On full blower. high heat .Direction to screen only. Keep like this for 10 minutes or so . Reasoning behind this ? The HVAC system is heating and conditioning air it's already heated so the demist works faster. But the air remains moisture laden, any longer than this you'll start to steam up again . So, after 10 minutes switch RECIRC off so that fresh air is drawn in from outside. Set your temp to a comfortable level.
This has worked for me on the MG4 and I tend not to bother with auto.

 

[Kithmo]

A couple of 1kg dehumidifier bags works for me, one on the dash and one on the back parcel shelf behind one of the headrests so it doesn't fly forward.

 

[Slipstream]

I can't imagine driving a car without heating in the winter. You know, like that stupid joke about electric cars freezing people.

I'll let you in on a secret. Even if it's very humid outside and you have the heater on with the air conditioning on (to keep the windows from fogging up), they still fog up.

Mine don't

Do you think that if the A/C and heating runs at fan speed 6 for 43 minutes and fails to defog the window in that time, that blowing on the glass with that button will help? It won't. It'll just hum loudly, maybe defog a little more, but that's about it...

Sounds to me there's something wrong with your HAVC system. Maybe a trip to the dealer.

 

[Buster72]

Mine don't

Mine neither.

 

[Martinonline]

After experimentation, correction to my previous post in that the recirc control does not change when demist selected.

 

[NLMGSAN]

I can write down a long discussion about the why, and particularly how EU cars suffer more from fogging up the windscreen than UK cars, but I will stick to some tips.
To explain them a little bit, I will first show you some numbers.

Suppose it is 3 degrees outside and the humidity is 100%. Baader will recognize this one... If you heat up this air when floating into a confined area (cabin) all the way to 15 degrees, it will directly drop the humidity in that air to 47%. Normally, this means the foggy inside of the windscreen will dry up quickly as this dryer air mixes with the moist air inside. Unless the windscreen remains too cold this will work (e.g. while driving).

Tip 1 Let in a good amount of the cold air before you start your trip and heat this up as much as possible. Consider recirculation for some minutes (but not too long because you breath out 'water' as well and you are quickly back to square one).
Tip 2 Use vents directed towards the windscreen only. Too cold? Seat and steering wheel heating (if available)
Tip 3 Reduce moisture in the car by placing a couple of dehumidifiers in the cabin. I have two in the back, two on the dash.

We have had the wettest six months since ages here. No issues with fogging up. Not even at 0 degrees in the snowstorm this morning.

 

[NickHeynes]

I can write down a long discussion about the why, and particularly how EU cars suffer more from fogging up the windscreen than UK cars, but I will stick to some tips.
To explain them a little bit, I will first show you some numbers.

Suppose it is 3 degrees outside and the humidity is 100%. Baader will recognize this one... If you heat up this air when floating into a confined area (cabin) all the way to 15 degrees, it will directly drop the humidity in that air to 47%. Normally, this means the foggy inside of the windscreen will dry up quickly as this dryer air mixes with the moist air inside. Unless the windscreen remains too cold this will work (e.g. while driving).

Tip 1 Let in a good amount of the cold air before you start your trip and heat this up as much as possible. Consider recirculation for some minutes (but not too long because you breath out 'water' as well and you are quickly back to square one).
Tip 2 Use vents directed towards the windscreen only. Too cold? Seat and steering wheel heating (if available)
Tip 3 Reduce moisture in the car by placing a couple of dehumidifiers in the cabin. I have two in the back, two on the dash.

We have had the wettest six months since ages here. No issues with fogging up. Not even at 0 degrees in the snowstorm this morning.

What I said pretty much (Except the humidifiers, which I haven't needed)

One extra point . Obviously the HVAC will have to work even harder if there's more people in the car. So if you regularly carry passengers you may need to turn the recirc off earlier.

 

[Todgy]

For a short answer to your question, no you are not the only one. I find it harder than in previous cars to get to a sort of equilibrium state of clear windows on the inside. Regularly I am driving along and all of a sudden I notice - ah it’s misting up again. This would not happen in my 2018 Skoda.

 

[Joningy]

Yes, I've never had a car fogging up so much, I've found turning on the heating / AC before I started driving, but that of course is costly on the battery, in an attempt to save the battery on longer trips turn off the heater, invariably it fogs up again in really cold weather.

 

[salty]

Yes, I've never had a car fogging up so much, I've found turning on the heating / AC before I started driving, but that of course is costly on the battery, in an attempt to save the battery on longer trips turn off the heater, invariably it fogs up again in really cold weather.

Catch 22 situation. Me personally the heater/AC would be on, so therefore clear windows. Simple's.
2 reasons, I hate being cold and I like clear windows. If range suffers, so be it. But that's me.

 

[Joningy]

Catch 22 situation. Me personally the heater/AC would be on, so therefore clear windows. Simple's.
2 reasons, I hate being cold and I like clear windows. If range suffers, so be it. But that's me.

Same here Salty.

 

[StevieM]

For a short answer to your question, no you are not the only one. I find it harder than in previous cars to get to a sort of equilibrium state of clear windows on the inside. Regularly I am driving along and all of a sudden I notice - ah it’s misting up again. This would not happen in my 2018 Skoda.

We had a Skoda Octavia previously and never had any problem with condensation.
I have a feeling there’s something in the DNA of this car that we are not aware of or at least I’m not aware of that is not visible to us but something in its build gives it a characteristic to produce a great deal of condensation.

We do find that the Aircon helps a lot and it is not become too much of a problem for us I am aware of it and I’m onto it!

 

[salty]

We had a Skoda Octavia previously and never had any problem with condensation.
I have a feeling there’s something in the DNA of this car that we are not aware of or at least I’m not aware of that is not visible to us but something in its build gives it a characteristic to produce a great deal of condensation.

We do find that the Aircon helps a lot and it is not become too much of a problem for us I am aware of it and I’m onto it!

There's that, characteristic word again.
MGs seem to have quite a few, "characteristics"
And your right, Air Con sorts it. Just leave it on, all the time. Won't do any harm. And just regulate what temperature and fan speed you want.

 

[Ian Key]

Yes, I've never had a car fogging up so much, I've found turning on the heating / AC before I started driving, but that of course is costly on the battery, in an attempt to save the battery on longer trips turn off the heater, invariably it fogs up again in really cold weather.

It depends on your definition of costly. Mileage wise it's only 8 to 10 miles over the whole journey of 200+ miles which can easily be recovered by a slightly lighter right foot. Cost wise if you are charging at home it's 15p to 20p.
Given the choice of being fogged up and cold or warm with clear windows I prefer spending 15p and having to recharge 8 miles sooner.

 

[Tight Git]

Have those that have really bad problems with this checked that there is no water getting in to the car in places it shouldn't?

There have been a few cases of water pooling in the boot and if you have an issue like this (or any other location) then you will have problems drying the car out.

 

[JonnyG]

I don't think this is an MG4 specific issue as I've seen similar threads on VW Golf forums too during the Winter months. The consensus there was that many modern cars suffer from condensation and the best way to reduce / resolve it is :-

1. Keep your A/C on all the time;
2. GIve your windows a good clean inside to remove any film and if you want, try an anti fogging coat on the interior to help reduce misting;
3. Try and keep the interior as dry as possible;
4. On a medium/long trip in dryer weather, set the interior temp to max (with fan speed high) and drop the windows a cm to help extract warm moist air from the car; and
5. Use dehumidifier bags on the dashboard if really needed.

 

[HazardLights]

AC on
Econ AC off
External air not recycle or auto air source
Windscreen and (optional) feet on

This is my default and it fixed the problem

 

[NLMGSAN]

AC on
Econ AC off
External air not recycle or auto air source
Windscreen and (optional) feet on

This is my default and it fixed the problem

Econ only has an effect on the time to clear the windscreen. Once cleared it does not matter in my ER.
This morning everything was fogged up except around the dehumidifiers. 10 minutes on econ, t=21 and fanspeed on three removed ice on the outside and fogged up windows. Rougly 0.7 kwh lost only.