[zenren]

The practice I follow is that the recirculation mode would be turned off only if the car steadily in 5th gear.

Originally Posted by Lobogris

I mostly keep my system in the fresh air mode, mostly on the blower as the outside air helps cool the cabin and reduces stuffiness. If the temp is very hot outside (more than 43 C), I will keep in on recycle. When passing through a dusty area, I switch on the re-circulation mode briefly until the air is clear again. I think people are too worried about this issue. After all when we walk around, we breathe in the outside air, when we are in a non air conditioned office or home, we breathe in the same air. If we have to pass through some dusty unpaved road or an area where it stinks, that is one thing. On normal drives the outside air is fine and I avoid excessive use of ac.

It depends on which city you are in as well as your daily commute route. Indian cities occupy almost half the slots in the list of 30 most polluted cities in the world. The pollutant levels in most of these cities are around 4 times the safe value, with Delhi topping the list with the value being around 6 times the safe limit.

So, if you are in one of these cities, the excessive inhalation of vehicle exhaust would lead to respiratory diseases as well as lung related issues down the line. If smoking is bad for health, inhaling exhaust gases from vehicles is no picnic either. In a non-air-conditioned office or home, no one is pumping out harmful exhaust near your windows and hence you are breathing a slightly better quality air at office or at home. The levels measured are typically averaged for a city which means the roads and industrial premises could be recording much higher values than residential complexes or other buildings with no emissions.

[DwarkaDelhiWala]

In Delhi, its impossible to drive even a short distance without the stench of a Nallah/Treatment Plant or a smoking chimney two-wheeler/3-wheeler/truck forcing in EVEN with closed circulating system.

I open windows only when near top of a flyover, that too never in west Delhi.

What we need is possibly an oxygen generator inside the cabin.

[joybhowmik]

Originally Posted by DwarkaDelhiWala

In Delhi, ...
What we need is possibly an oxygen generator inside the cabin.

See this thread for a possible solution

[DMajumdar]

Originally Posted by Gansan

I recently serviced my car at MSM and was accompanied by a service advisor during the post service road test. As the current climate is not warm, I normally drive around with ony the blower running, with the AC vent in fresh air mode and windows rolled up. The SA noticed this and remarked I should always keep the vent closed otherwise lot of dust will accumulate in the cooling coil of the AC, necessitating premature overhaul. He said I should open the window for fresh air.

This got me a bit confused. Even during summer, when I go for long highway drives with the ac on, I periodically open and close the vent to allow fresh air in the cabin. Is there any truth in what the SA says? Can someone clarify?

Haha! I used to do the same thing. I'd read somewhere that keeping your windows rolled up, especially at speeds above 50KMPH, increases fuel efficiency due to reduced air resistance. You'd save fuel even if you ran the AC at higher speeds as opposed to driving with them rolled down. But the dusty air flowing through your AC ducts will do a lot of damage by reducing the efficiency of your air conditioner. Recently however, I installed an HVAC filter, but I guess it only filters the recirculated air as it gets sucked up by the blower from underneath the dashboard.

[keeprevving]

Do you feel a difference in driveability when a car is in Recirculation Mode and Fresh-Air Mode. I drive two cars, and I see a difference in both. I have experienced a marginal reduction in power (may be a bit) in Fresh-Air mode. Is it psychological, or it actually happens? Sorry if my question sounds a bit lame.

[Aroy]

Originally Posted by DMajumdar

Haha! I used to do the same thing. I'd read somewhere that keeping your windows rolled up, especially at speeds above 50KMPH, increases fuel efficiency due to reduced air resistance. You'd save fuel even if you ran the AC at higher speeds as opposed to driving with them rolled down. But the dusty air flowing through your AC ducts will do a lot of damage by reducing the efficiency of your air conditioner. Recently however, I installed an HVAC filter, but I guess it only filters the recirculated air as it gets sucked up by the blower from underneath the dashboard.

I always drive in recirculating mode with fan on. Yes a lot of dust will enter in fresh air mode, and in Delhi that is a fact of life. The only time that I use fresh air mode is early morning in winters when there is less dust. The first time I use fresh air after a long time, a lot of accumulated dust blows out.

[Rahul Bhalgat]

Originally Posted by keeprevving

Do you feel a difference in driveability when a car is in Recirculation Mode and Fresh-Air Mode. I drive two cars, and I see a difference in both. I have experienced a marginal reduction in power (may be a bit) in Fresh-Air mode. Is it psychological, or it actually happens? Sorry if my question sounds a bit lame.

Hi keeprevving,
If your car has automatic climate control and if the cabin has already been cooled, then switching over to fresh air mode will put higher load on the AC (because it is taking in warmer air).

But, if the cabin temperature is equal to the outside temperature (like at the beginning of the drive), then you will not feel any difference of engine power between the two modes.

[alpha1]

Originally Posted by keeprevving

Do you feel a difference in driveability when a car is in Recirculation Mode and Fresh-Air Mode. I drive two cars, and I see a difference in both. I have experienced a marginal reduction in power (may be a bit) in Fresh-Air mode. Is it psychological, or it actually happens? Sorry if my question sounds a bit lame.

I am sure car acs does not have inverter technology.
That means when the compressor operates, it is on full load.

Whether you have fresh air mode or circulation mode is immaterial.

Compressor + condensor fan robs some 3-4 hp of power.

But if you average the wheel power over a period of time (say 1 hour), then what Rahul has mentioned comes into play:

Originally Posted by Rahul Bhalgat

Hi keeprevving,
If your car has automatic climate control and if the cabin has already been cooled, then switching over to fresh air mode will put higher load on the AC (because it is taking in warmer air).

Or in other words:
In fresh air mode, the compressor is switched on for longer duration to cool the air to same temp.
In recycle mode, the compressor is switched on for shorter duration to cool the air to same temp.

[gearbox]

My Swift (Old 1.3L Engine), literally kills the FE when on "fresh air" mode. I recently traveled to Thiruvannamalai from Bangalore and throughout I had to use fresh air mode, since the cover that stops fresh air entering the AC system has been totally destroyed by rats. Now to get this sorted, I need to replace the cover that enables re circulation, which costs nothing really, but then the actual cost is to get the entire dashboard out to replace it, and that costs a bomb, and then some.

It is so stupid of Maruti to leave a huge area open, just under the left wiper base, that acts as the input for fresh air inside the AC, and rats can easily bite off the rubbery things on the hinge sides of the bonnet, and then easily enter the AC system and even the cabin through the AC Vent hole.

This is how mine was damaged, I now have dual steel mesh that blocks anything coming inside the AC vent system from outside. But not before the ASC removed about 15 pups from inside that inlet.

I am kind of tired of my car now, squeaks, noise, rats get just about anywhere, ASC's never have parts, saying "these are not commonly consumed parts saar".

I have to get it fixed anyways, hope this time it will be fine.

[somebodystopme]

Hello friends
I am facing a strange issue with my skoda superb 2012. When the air conditioning is on, i can easily switch on air circulation mode hence cut out fresh air mode. But winter has set in and i mostly dont use air conditioning, i keep it switched off. Now when the ac is off and i press air recirculation button nothing happens its non responsive and car forces fresh air mode by default which is quite polluted since I am from Delhi.

Is something wrong with my air conditioner? Has anyone faced a similar issue? Whats the work around? Please suggest.
Thanks

[VW2010]

Is something wrong with my air conditioner? Has anyone faced a similar issue? Whats the work around? Please suggest.

If i remember right you have to switch to "Auto" and let the system choose everything, then switch off the AC (button) and then enable the air circulation button. This way air simply recirculates without Air Con.

Better option is to let the Air Con run on Auto mode with temperature set to higher 20's and keep the Air Circulation button on. This way you are not straining the Air Con at the same time ensuring the temperature is also maintained.

Winter is tricky for without the Air it can get stuffy while outside air is not clearly smelling good

I usually set the air con to automatic mode and run it slightly cooler inside.

[gearbox]

I have a silly question, does using the non recirculation mode puts less load on the AC and may help get a bit more mileage?

[kkkkkaran]

Originally Posted by gearbox

I have a silly question, does using the non recirculation mode puts less load on the AC and may help get a bit more mileage?

Its actually the other way around. In fresh air mode, the air taken into the AC compressor is hot, especially during summer, taking longer time to cool, and hence more load on the engine.
In recirculation, once the cabin is already cooled, it does not take much energy to keep the temperature maintained.

[callvvijay]

Originally Posted by gearbox

I have a silly question, does using the non recirculation mode puts less load on the AC and may help get a bit more mileage?

Originally Posted by kkkkkaran

Its actually the other way around. In fresh air mode, the air taken into the AC compressor is hot, especially during summer, taking longer time to cool, and hence more load on the engine.
In recirculation, once the cabin is already cooled, it does not take much energy to keep the temperature maintained.

Agree with karan here.

A slight OT here. When I took my Alto for A/C service to Senthil (he has got very good reviews in T-BHP), he suggested to NOT use the fresh-air (non-recirculation) mode. The reason being, cars like Alto (the basic ones) do not have the air filter which results in the dust/dirt getting accumulated in the compressor very soon. He had suggested me to open the window for first few mins with the AC on instead.

[Gansan]

^^ I don't put it on fresh air mode in the city or short drives, and will keep the windows open for the first couple of KM. But on highway drives where we do not take breaks for a couple or three hours at a stretch, I do put it on fresh air mode for about ten minutes every hour or so. I actually give the task to my son in the front passenger seat!

Much less chance of dust on the highways, and our health is more important than that of the ac coil! Keeping the windows open even partially at highway speeds is not practical.