Do you use your air con?

[Harvey1512]

Originally Posted by GMcL

20ᵒC in Northumberland again Harvey ?

Growing up on the coast there, anything above 17 was considered a hot day followed by three days sea fog.

Haha. I live inland so it has been 25c for the last 3 days. I used to live in Amble, my inlaws live in Alnmouth so I know all about a chilly sea fret. The difference can be crazy, a good 7-8c at times between coastal and inland, as you will know.

You are dead right about the temperatures. Anything above 17c and everyone is in shorts. I couldn't handle south of England temps. Seeing regular temps in the high 20's, low 30's down there doesn't fill me with any envy.

[hennabm]

On my cars that have it - yes I do use it all the time. As said already in this thread, it provides dry air so therefore reduces condensation on colder days. Warmer days speak for themselves.

With my 240, I use the "analogue air con" and use the vents on the A pillars as I find them very effective at providing cooler air on the move. When standing, I have to use those funny little handle things on the inside of the door to lower the windows

[canis]

I never had air-con until I got the T4 last year. The previous V40 had it, but it was empty of it's freon and left unused. I know it was empty, because I emptied it. Which is a £2000 fine, iirc???

It's perfectly obvious the V40 had air-con added as an afterthought. One glance at the routing of the pipework involved shows this, and it's a bloody nuisance. Gets in the way of just about everything. My opinion was to remove the entire shebang and fit a smaller auxilliary belt. But the wife, who owns the car, objected to this plan. So the air-con remained in place, useless and unused.

The T4 air-con actually worked. And it's the full proper climate controlled version too. Automatic temperature control, which works just not as good as you might expect. I still have to turn the temp up when i'm cold, and down when i'm hot, the idea that it has a thermostat taking care of temperature just doesn't hit the mark. Great idea in principle - if only it actually did it's job. This isn't a malfunction, it's simply not built very well.

What other posters have said about the dehumidified air and demisting - absolutely spot on. That's been my experience too. It's brilliant at clearing the screen, even in winter when the engine isn't yet hot.

But it does sap enormous power from the engine. Those who are saying it doesn't must drive very slowly. The compressor gives enormous drag to the engine, you can hear it when it starts. Immediate RPM drop, and the idle bypass valve opens to take up the drop.

I'm rather concerned about the environmental cost. Freon horrible for the atmosphere and they will all leak eventually. And how many garages are releasing this stuff ("It's alright, we'll get nextdoor to re-gas it for you. It'll work better then too! It only costs £30!") to get access to engine components and just hoping nobody will notice - i shudder to think. The extra effort to pump this stuff around - and yet people will rattle on about saving one tenth of a penny from their petrol station, but drive around with the air-con on all the time. The loss of one mile per gallon due to tyre-pressures and they'll rant about safety and economy, yet drive aroudn witht he air-con all the time. This is hugely wasteful, though i realise int he grand scheme of entire buildings being made not only cool, but actually cold as a mark of status and economic muscle, will render this effect minimal. Nevertheless, it bothers me.

Then there's driver habits. I can well imagine thousands of cars every day attempting to squeeze every last kilojoule of heat the vehicle has stocked up through that tiny half-inch pipe. Now if the climate control controlled the windows too - that'd be something. ("lol") It's completely insane to get into a hot car and use the air-con to cool it. ("What???") It's grossly inefficient. ("I can afford it!") The real loser is, of course, the environment. ("Oh shut up you tree-hugger!")

[Laird Scooby]

Originally Posted by canis

The T4 air-con actually worked. And it's the full proper climate controlled version too. Automatic temperature control, which works just not as good as you might expect. I still have to turn the temp up when i'm cold, and down when i'm hot, the idea that it has a thermostat taking care of temperature just doesn't hit the mark. Great idea in principle - if only it actually did it's job. This isn't a malfunction, it's simply not built very well.


But it does sap enormous power from the engine. Those who are saying it doesn't must drive very slowly. The compressor gives enormous drag to the engine, you can hear it when it starts. Immediate RPM drop, and the idle bypass valve opens to take up the drop.

I'm rather concerned about the environmental cost. Freon horrible for the atmosphere and they will all leak eventually. And how many garages are releasing this stuff ("It's alright, we'll get nextdoor to re-gas it for you. It'll work better then too! It only costs £30!") to get access to engine components and just hoping nobody will notice - i shudder to think. The extra effort to pump this stuff around - and yet people will rattle on about saving one tenth of a penny from their petrol station, but drive around with the air-con on all the time. The loss of one mile per gallon due to tyre-pressures and they'll rant about safety and economy, yet drive aroudn witht he air-con all the time. This is hugely wasteful, though i realise int he grand scheme of entire buildings being made not only cool, but actually cold as a mark of status and economic muscle, will render this effect minimal. Nevertheless, it bothers me.

Then there's driver habits. I can well imagine thousands of cars every day attempting to squeeze every last kilojoule of heat the vehicle has stocked up through that tiny half-inch pipe. Now if the climate control controlled the windows too - that'd be something. ("lol") It's completely insane to get into a hot car and use the air-con to cool it. ("What???") It's grossly inefficient. ("I can afford it!") The real loser is, of course, the environment. ("Oh shut up you tree-hugger!")

If your temperature control isn't working well, it might be an idea to locate the cabin sensor and give it a clean - a soft brush and a vacuum cleaner usually work well. Be gentle with it, it's fragile!

If the engine is idling and you switch the A/C on, yes it will drop the idle speed. Don't forget though, the idle mixture on a more modern engine like in a V40 is set to use the absolute minimum of fuel to meet emissions. This means there is no "fat in the system" to accommodate extra loads such as lights, heated rear window, A/C and so on, meaning the AICV has to take up the slack. Obviously not so much with the lights, HRW etc but it's exactly the same.

As has been said many times, the drag of opening windows causes more fuel to be used than driving round with the A/C on and is a lot noisier too. A well used and maintained A/C system is also less likely to leak.

Getting into a hot car and using the A/C alone to cool it isn't very efficient, you're right. Using the windows to let the first and worst of the excess heat out while the A/C system starts pulling down is in fact a recommended procedure.

I'm sure you've seen puddles forming under cars when they are parked after a run. This is ice melting off the evaporator and draining out the drain tube. The ice is formed by the moisture extracted from the air and is made worse by using the A/C with the window open, much the same as your fridge at home will develop haw frost if the door is left open - excatly the same thing.

What you've pointed out is many people don't really understand A/C and that's where 90% of the problems begin and end.

[phil1968]

The A/C compressor saps about 5 hp, about the same as the power steering pump & alternator combined. If you think about it, the engine is only generating probably twice that at idle, so no wonder the rpm drops when the A/C is turned on. The most recently used refrigerants (R134a & R1234yf) do not deplete the ozone, they do however contribute to greenhouse gas production. The previously used refrigerant, R12, was used up until the early 90s & that did contribute to ozone depletion. "Freon" is a trade name BTW, the same way you'd call a vacuum cleaner a "Hoover" or "Sellotape" sticky tape.
Going slightly off-topic, I work as a contractor for a large pub chain & their policy is to open all external doors in the pub when the outside temperature goes above 21 deg. C with the aircon going flat out. Go figure

[Laird Scooby]

Originally Posted by phil1968

The A/C compressor saps about 5 hp, about the same as the power steering pump & alternator combined. If you think about it, the engine is only generating probably twice that at idle, so no wonder the rpm drops when the A/C is turned on. The most recently used refrigerants (R134a & R1234yf) do not deplete the ozone, they do however contribute to greenhouse gas production. The previously used refrigerant, R12, was used up until the early 90s & that did contribute to ozone depletion. "Freon" is a trade name BTW, the same way you'd call a vacuum cleaner a "Hoover" or "Sellotape" sticky tape.
Going slightly off-topic, I work as a contractor for a large pub chain & their policy is to open all external doors in the pub when the outside temperature goes above 21 deg. C with the aircon going flat out. Go figure

Whoever sets the policy for that pub chain needs to sober up, stop drinking the pub chains products and smell the coffee and change the policy!

Just to expand on the alternator consumption, the alternator in mine is 120A @ 14V = 1680W if all of its output is being used. As most wound components are about 80% efficient, that means it uses about 2100W to drive it or just under 3hp. One horsepower is approximately 750W (actual figure is near 746 but i can't remember it off the top of my head) to give an idea of the conversion.

However, both the alternator and PAS pump only present load to the engine if they are being used - the laternator will almost always be providing some charge, even if only a few Amps to cover the basics. The PAS pump will freewheel until it's called on to move the steering though.

The big difference is most of the cars we talk about on here have Constant Displacement compressors. This means they are either on or off, much like your fridge at home. Later cars from the late 90s on generally have Variable Displacement compressors which only work as much as is needed to bring the temperature down to the level needed so aren't shuttling on/off like the older Constant Displacement variety.

With the compressors we have, they will be felt to "kick in" and as pointed out above, the engine is not making much more than what the compressor needs in terms of power with the minimal fueling for a clean idle.

[canis]

Phil, Scoob, thank you both. I feel a bit better about it now.

One problem with air-con which hasn't been addressed - need the windows open to smoke!

I think I can guess what the solution to that is!

[Laird Scooby]

Originally Posted by canis

Phil, Scoob, thank you both. I feel a bit better about it now.

One problem with air-con which hasn't been addressed - need the windows open to smoke!

I think I can guess what the solution to that is!

Sometime using the A/C the moisture that gets drawn out can fog up the windows temporarily so opening the window to let the moisture out is good. Opening it while having a smoke then closing again after is kind of the same thing.

[phil1968]

Originally Posted by canis

Phil, Scoob, thank you both. I feel a bit better about it now.

One problem with air-con which hasn't been addressed - need the windows open to smoke!

I think I can guess what the solution to that is!

TBH in warm weather I have the windows down & the A/C turned off in both my car & van around town at sub-30 mph speeds. Obviously I turn the A/C off on the C70 when the roof's down, but I make the conscious decision to do that as in the handbook it says that the A/C is "subdued" when the roof's down, but I'd rather turn it off physically myself to make sure it's completely off. I have the windows closed & the A/C on above those speeds & crack the window open about 2 inches during a smoke