Auto Climate Control & AC always on - Hyundai

faceman

This might be obvious to everyone bar but gonna ask. I have a Hyundai I40 with an automatic climate control feature. When you hit Auto, regardless of the temperature set, the AC button is also lit. I dont know if that means its constantly conditioning the air or whether it just means the feature is enabled for use.

I tend to set climate control manually but Im wondering if its in vain. Does using the Auto function run the AC at a level that would add to fuel costs?

Cheers!

Atlantic Dawn

Yes this is normal, Auto will put on A/C and result will be heating/cooling the car until that temperature is achieved. The fuel difference is tiny in modern cars, I leave mine on permanently.

bigtimecharlie

My 09 BMW does that also. I believe it will only use the Air Con when it wants to so it acts as a normal HVAC system most of the time.

The Air Con on with auto climate can be coded out, not sure with the I40.

zg3409

A/c is used intermittently to demist front windscreen and reduce humidity of car. It does this particularly at start of trip. On all cars it's important to turn on a/c every so often as this helps lubricate seals and without this, say a/c off all winter your a/c will leak gas and stop working.

Gregor Samsa

There’s really no reason to ever turn AC off. It may use a small bit more fuel, but so does using your wipers, your headlights, the radio, etc etc.

AC isn’t just about cooling the air - the fact that it dehumidifies it is probably it’s most important feature. So even on a cold, wet winter’s day when you have hot air blowing, it’s taking the excess moisture out, meaning your windows won’t fog and the air will be more comfortable. Plus as mentioned, the AC system thrives on being used, as the gas contains lubricants that keep the seals in shape while it’s flowing around. If you leave it off for extended periods of time, the seals leak and you lose gas - and with it AC performance.

Best bet on a modern car is to select your comfort temperature (or temperatures, if you have multiple zones), stick it on Auto, and forget about it. Setting the temp to max or min won’t heat it or cool the car any quicker that just setting it at the temperature you actually want in the car. And unless you need to clear an already foggy (or frozen) windscreen, blasting the fans doesn’t help get the temperature set any faster and just makes more noise.

AC on, set temp to 21/22 degrees, leave it on auto. Job done.

colm_mcm

I’d turn off aircon if trying to defrost the car on a cold morning, if the engine is cold, the AC will make the air even colder. Once engine is up to temp I’d turn it back on as it keeps windows clear.

Other than that it stays on all year round.

zilog_jones

https://www.boards.ie/discussion/comment/118636497#Comment_118636497

This isn't applicable to all cars, only those with belt-driven compressors. On cars with electric compressors like most hybrids and all EVs, there's no shaft seal to start leaking if not used.

On my Prius and other Toyotas I've used with climate control, I can turn off the AC while leaving Auto on. I don't have enough experience with Hyundais to know if the same can be done with them.