[TorquePull]

B-pillar mounted blowers on the XUV500 are the worst. It failed terribly to cool the cabin and airflow from the front had to be redirected for effective cooling.

The second worst are the center console, they are just placed way too low to cover upper body.

Roof mounted blowers are the best at effective cooling. Marazzo has a unique setup, that provides effective cooling using direct and diffused blowers for day and night. Only car with roof mounted blower that was comfortable at colder nights.

[kaps454]

Voted for B-pillars even though roof is the best option

With Sunroofs being such a rage, roofs are actually out of the question, even though it is the simplest option, no ducting, just a blower that blows in air from the aft part of the car to the rear. Simple, reliable, cheap.

Leaves B-pillars and central console, B-pillars are a lot more convenient and less obtrusive.

regards kaps454

[HillMan]

I voted roof. This is the best for third row seating. Something like what the Kia Carens has. For the second row the B Pillars are the best location otherwise to get some extra air. Because there is direct air blast from the dashboard vents that flow between the front two seats. So there will be overall cooling at the back.

[HammerHead]

Voted other.

No matter where the A/C vents are placed, I need ventilated seats to keep me cool.

[anupmpatilbyd]

I think roof mounted (or anything above head) would be ideal. No matter what make or build the vehicle is. Cause, hot air will rises up and cold air is dense so, it settles down. Upper position will ensure the cabin to cool down quickly and maintain the temperature throughout the ride.

[alkaknar]

Originally Posted by anupmpatilbyd

I think roof mounted (or anything above head) would be ideal. No matter what make or build the vehicle is. Cause, hot air will rises up and cold air is dense so, it settles down. Upper position will ensure the cabin to cool down quickly and maintain the temperature throughout the ride.

Why not under the seats, for example? Wouldn't that be just as effective?

[anupmpatilbyd]

Originally Posted by alkaknar

Why not under the seats, for example? Wouldn't that be just as effective?

How would that allow the air to circulate? Basically, hot/warm air is light and cold air is dense. So, naturally, the temperature gradient between the upper and lower will allow the air to circulate on its own.

Putting it under the seats (presume it's ventilated seats) will immediately have effect of cooling. But, on longer journeys, I would like the whole of the cars' atmosphere to have same temperature. So, to satisfy that, placing ac vents on the roofs will allow the cold air move from the roof to the floor and the hot air vise versa.

You could experiment it with your front row ac vents. Just blow the vents to the lower (legs) only and sit for a minute. Once you feel uneasy, switch it back to normal, you can notice the difference it makes.

[RGK]

Voted "Roof".

The main advantage is that the air conditioning coverage is more extensive and there is no tampering by kids.

The third-row AC in Crysta does not offer separate controls, requiring the vents to be closed manually.

[SLK]

Originally Posted by anupmpatilbyd

Basically, hot/warm air is light and cold air is dense. So, naturally, the temperature gradient between the upper and lower will allow the air to circulate on its own.

OK - I did vote for roof, but I would like to share my experience and clarify the difference between theory and practical.

Under most situations you would want car AC to give you direct air and that is what is the most comfortable in above normal temperatures. Since the hot air is light, it is on the top and when the AC takes that in, it is able to cool it down say by 20 deg C (say from 40 to 20), however the vent that is drawing air from under the dash, takes in 30 and gives out 10 deg C, which actually feels much better directly on your body. So in terms of getting chilled air, the lower vents are always better.

The roof vents at rear are considered better because the alternatives are either too low or too much on the side, and mostly without even a dedicated cooling coil and fan.

Basically the concept is not cooling the cabin, it is how cold air can you get from your AC directed at where you are sitting. The cabin can't stay cool even for 60 seconds if you turn the AC off, therefore that is not the objective.

My house is almost the same! a lot of glass and top floor, a 2ton window AC mounted near the floor is 2x more effective for quick relief from 40 deg C inside the house (yes!) than 2T split near the ceiling.

Also consider this, when cold air is sitting low near the floor, recirculating that to body/ face level is better than trying to cool very hot air.

[GeeTee TSI]

Voted for B pillar but the roof is also a close second pick for me. What is overdue is a proper (and I mean proper) set of HVAC controls for the rear passengers democratising atleast blower speed controls across segments.

Personally I prefer the AC air flow on my face/forehead and the B pillar is positioned perfectly in my opinion (a typical, comfortable use case in my view does not included the 5th passenger)

[Ravi Parwan]

Roof mounted AC with a separate evaporator coil is the best. I have seen even roof mounted blowers that worked well to cool Eecos and Taveras without the roof mounted AC.

The central console AC without a dedicated blower is pretty much useless. Either the airflow is too weak, or it cools just the knees, like in the first gen Scorpio. I swear, while the rest of the passengers kept cribbing about the heat, the middle passenger used to have to keep contorting to keep from freezing their knees.

I do feel a central mounted vent with blower plus B pilllar vents with a dedicated evaporator is the best implementation for sedans with low roofs, while SUVs and MUVs should have roof mounted units with no regards to the sunroof.

[PetrolHead2272]

Originally Posted by GTO

I have yet to sit in a car that has powerful (and I mean p-o-w-e-r-f-u-l) rear AC vents in the most common position, that is between the front seats (the tail end of the center console).

I recently bought a Scorpio N and according to me the rear AC is pretty chilly. It doesn't take much time to cool the rear two rows of the car even in Delhi heat. I would say the AC effectiveness is similar to the first gen Innova I had before which had roof mounted AC vents.