Air-con with the windows open

[StuartGGray]

I was doing the garden today, chopping a lot of hedge. Stuffed a lot of it in the back of the V70 to take to the tip.
I was sweating like a rapist and the car showed 28c outside, which is pretty impressive for Scotland. I cranked up the air con to full but left the windows open, front and rear to empty the car of hot air as I drove along. After a few minutes I shut the back windows but left the fronts open. The air con kicked in after a few minutes, covering me in lovely cold air with the blower at full chat. I left the windows open because it was also nice to have a heat on my arm.
Any reason why I can't do this? It is manual air con in a Volvo V70 P2 Torslanda (read poverty spec)

[LighthouseTrait]

I do this all the time.... You get a cool breeze and also enjoy the summer heat!

[Ari]

You can do whatever you like mate, it's your car!

[Ozzie Osmond]

Why not use the heated seats as well?

[Urban Sports]

I spent 3 weeks in Spain recently and had junior in the back with us, the only way to cool the car was to stick the CC on full cool and open the widows for a while.

It worked a treat for me so therefore must be the best way.

[SWoll]

Once decent CC/AC is blowing ice-cold I would have thought that opening the windows would defeat the purpose and if anything warm the car up, as well as being st for economy.

[StuartGGray]

So it won't break anything? The handbook or a mate, can't remember which, says to have the windows up, put it on recirc, put the air con on and after 8 minutes it will begin to cool. I thought that was bks. The only time I use recirc is with the windows up when passing a place of known whiff. Seals the car.
I'll carry on as I have been then. - Cheers!

[craigjm]

Opening the windows causes the AC to be less effective. Doesn't stop it working but it makes it work harder to cool down the space and obviously the air is always changing and thus keeping a steady temperature is difficult.

[carl_w]

I've been doing this a fair bit lately. With the blowers on and no AC warm air comes out of the vents. For sure it would be more efficient to close the windows, but I'm liking the cool air from the vents plus the engine noise through the open windows. And it's nice to get unfiltered air too.

[StuartGGray]

SWoll said:

Once decent CC/AC is blowing ice-cold I would have thought that opening the windows would defeat the purpose and if anything warm the car up, as well as being st for economy.

To be honest, I don't think a 2.4 petrol engine suffers from poor economy with the air con on. I've always kept the air con on if needed and have never noticed a change. I have noticed the last tank of fuel has lasted more than usual after towing a caravan. I pumped up my all-season Klebers to 41 psi from 29 psi as per the Volvo handbook, but forgot to put them back down after towing the caravan. While towing the caravan I got 30 mpg, but now, after a refill of the tank and using proper sums I am on 425 miles and the warning light has still not come on. It won't for a while yet according the the position of the needle. It usually comes on at 370 miles max with usual use with the tyres at 29 psi and not towing a caravan.

[TheTurbonator]

The reason it tells you to put the recirculated air on, is that it puts less strain on the system if the interior of the car is cooler than the outside temperature.

If it's 25c outside and you've had the air con on and cooled the car down to 21c, then the system is drawing colder air into it and not having to work as hard to cool it.

[SWoll]

StuartGGray said:

SWoll said:

Once decent CC/AC is blowing ice-cold I would have thought that opening the windows would defeat the purpose and if anything warm the car up, as well as being st for economy.

To be honest, I don't think a 2.4 petrol engine suffers from poor economy with the air con on. I've always kept the air con on if needed and have never noticed a change. I have noticed the last tank of fuel has lasted more than usual after towing a caravan. I pumped up my all-season Klebers to 41 psi from 29 psi as per the Volvo handbook, but forgot to put them back down after towing the caravan. While towing the caravan I got 30 mpg, but now, after a refill of the tank and using proper sums I am on 425 miles and the warning light has still not come on. It won't for a while yet according the the position of the needle. It usually comes on at 370 miles max with usual use with the tyres at 29 psi and not towing a caravan.

Economy comment was more relating to windows down TBH. AC losses for a decent size engine at speed are negligable as you suggest, losses from open windows causing drag are far greater I believe.

[falkster]

Ozzie Osmond said:

Why not use the heated seats as well?

Nothing like cool air on the face, warm air on the arm and a litre of sweat running down the arse crack.

[bennyboydurham]

Having lived in the Middle East where summer tops out at 51 degrees, the OM is this; hop into car, AC on full recirc. Drive off, windows open to get a bit of air moving inside the cabin. When the AC begins to get fully cold, close the windows. I was told that driving along with the windows open and the AC on recirc clogs up your cabin filter, although that's probably bks. On the rare occasions I get in and drive with the window down, I usually turn the AC and climate off altogether.

[stuartmmcfc]

by complete coincidence i was reading the handbook of my xkr tonight and it actually said if the car was hot inside the most effective way to cool it was to have the air con on and the windows open for the first few minutes to allow the hot air to escape.

[Fireblade69]

Ari said:

You can do whatever you like mate, it's your car!

Nice

[essayer]

When I had a the convertible I used to have the roof down and AC on

[SWoll]

falkster said:

Ozzie Osmond said:

Why not use the heated seats as well?

Nothing like cool air on the face, warm air on the arm and a litre of sweat running down the arse crack.

You need a MB/BMW with cooling seats. Bliss.

Hate to think how much all that stuff weighs though...

[craigjm]

stuartmmcfc said:

by complete coincidence i was reading the handbook of my xkr tonight and it actually said if the car was hot inside the most effective way to cool it was to have the air con on and the windows open for the first few minutes to allow the hot air to escape.

It is because the still air in the car after it has been parked is likely to be warmer than that outside so it is always best to open the window even for a minute when you first drive off in hot weather.

[stuartmmcfc]

craigjm said:

It is because the still air in the car after it has been parked is likely to be warmer than that outside so it is always best to open the window even for a minute when you first drive off in hot weather.

thanks for the physics lesson but the point i was making was that Jaguar don't say " turn the air con on full blast and keep the windows closed so it can work at its most efficent' or "open your windows and don't bother with the air con as it'd be a waste of time" but do both even though it's been sugested earlier that open windows and air con don't go together.