[BarryJI]

Now that it's winter in Los Angeles, or as close as we get to it, I like to switch the a/c in my 228i off. This is a habit I acquired many years ago, driving European sports cars with 4-cylinder engines which, with the a/c on, produced all the power of a ride-on lawn mower. This does not apply to the better-engineered BMW, whose power output does not appear to take too much of a hit from a/c use because -- I think -- the thermostat will simply turn it off when the climate setting is on Auto and the interior temperature matches that set by the driver.

Somewhat to my surprise, I have noticed that the car gets very hot inside, even in cold weather. For example, when I get into the car it might be 56 degrees outside but it's stuffy and well over the 70 degree temperature inside the cabin that is the standard comfort level for me. I am a little baffled that I need to cool the car interior down using a/c, even when I have not left it in the sun, when the outside temp is quite moderate.

Does the car vent a lot of heat from the hard-working engine into the cabin, heat which using a/c all the time, even in the winter, is designed to dissipate? The little red/blue heat setting wheel on the dash does a very good job dialing down over-aggressive a/c cooling, but I do wonder why the car seems designed to be run on Auto temperature mode all the time, even in cool weather. It seems to me that -- correct me if I am wrong -- the car's climate control system will actually disengage the a/c if it's not needed, even when the green a/c light is showing?

I'm not complaining, just curious. I could always drive with the windows down, but in Los Angeles, the traffic noise and pollution make that not a good idea. I think perhaps the car is engineered to have a/c on when the windows are shut, even in the winter, because it does not really diminish power output and appears not to operate, even when switched on, when driver-set temperature levels are achieved.

The design and engineering of this car, especially in the many areas where it seeks to automate functions that some -- older -- drivers are used to controlling completely manually, is impressive. The car appears to have a much finer control of cabin temperatures via sophisticated thermostats than I have experienced before. My question is: am I fighting this, unnecessarily, by attempting to run the car in moderate-to-cold conditions with the a/c setting off by default?

[AlpsRider]

I also turn off the a/c when the temp drops below 70, then turn the thermostat down to 65 which activates the fan at a higher speed. If my car has been sitting in the sun, I blast the a/c on max just to cool it down, then switch it off. The sunroof works well at slower speeds but on the freeway I usually close it. I had Photosync tint installed on the windows which makes a big difference with solar heating in the cabin.

[BarryJI]

Good advice, thank you. I have tints all round, too, but the cabin is small and heats up fast.

[Cyberdemon]

What do you have the circulation control set to? There are 3 settings (auto, manual, off). If you are recirculating the air in the cabin you aren't bringing in any of the fresh air from outside.

Keep in mind, these days it is better to leave the car on automatic. The AC compressor does not just function to make the air colder, it removes humidity. The system in the BMW should automatically switch the compressor on and off as needed.

[BarryJI]

Thanks, yes, I am adapting to a design philosophy that places a lot of functionality onto "smart" tech that used to be a hands-on task for the driver. I am beginning to appreciate the desirability of leaving a/c ON (because, as you say, it does not cause the compressor to be always running) and air recirculation to AUTO. I have never had a car that automates air recirculation before, nor one with "smart" climate control. It feels odd to be running a/c in the winter but as long as it does not pull power from the engine when it doesn't need to, then I will happily submit to BMW's design philosophy.

[AlpsRider]

Originally Posted by BarryJI

Thanks, yes, I am adapting to a design philosophy that places a lot of functionality onto "smart" tech that used to be a hands-on task for the driver. I am beginning to appreciate the desirability of leaving a/c ON (because, as you say, it does not cause the compressor to be always running) and air recirculation to AUTO. I have never had a car that automates air recirculation before, nor one with "smart" climate control. It feels odd to be running a/c in the winter but as long as it does not pull power from the engine when it doesn't need to, then I will happily submit to BMW's design philosophy.

I have the same older tech ideas. The thing is that with previous cars I could always feel or hear the compressor come on, however my M235i is so quiet and has so much power I can't tell if the compressor is on or not. I guess that is a good thing, but I just don't trust the system. It would be nice if there were a way to know when it comes on. Some of my previous cars would turn on the a/c compressor whenever I switched the vents to defrost, it wouldn't matter if it was 35 degrees outside. If you didn't change the vent selection, you would just drive around all day with the a/c on!

[Cyberdemon]

FYI I can't confirm if this is still the case, but previously my understanding was BMW's will also automatically shut the compressor down at WOT, so if your concern is losing power when mashing the gas, you won't.

[AlpsRider]

Originally Posted by Cyberdemon

FYI I can't confirm if this is still the case, but previously my understanding was BMW's will also automatically shut the compressor down at WOT, so if your concern is losing power when mashing the gas, you won't.

Well fuel economy is also a consideration, especially when it is below 68 degrees outside, it seems silly in a dry climate to run the compressor.

[BarryJI]

Originally Posted by AlpsRider

I can't tell if the compressor is on or not. I guess that is a good thing, but I just don't trust the system. It would be nice if there were a way to know when it comes on.

RPMs at idle is a very good indication. It idles higher to output power to the compressor. I like it when it settles down on the lower number.