Car Air Conditioning: Energy Usage & Benefits

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Discussion Overview

The discussion revolves around the energy usage and efficiency of car air conditioning systems, particularly comparing the continuous operation of the AC versus intermittent use while keeping the fan and vents running. Participants explore the mechanics of car AC systems, their operational modes, and the implications for energy consumption and comfort.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that running the AC continuously consumes significantly more energy than just using the fan, as the compressor is belt-driven and affects fuel efficiency.
  • Others argue that running the AC intermittently may be more efficient due to the nature of car AC systems, which do not vary capacity effectively.
  • It is noted that the efficiency of the AC system may depend on how the user selects temperature set points compared to the car's built-in settings.
  • Some participants mention that many cars do not have thermostats that cycle the AC compressor, while newer models may have such systems that optimize performance.
  • There is speculation about whether keeping the fan on with open vents allows warm air to enter the car, potentially affecting cooling efficiency.
  • Participants discuss the mechanics of how car AC systems operate, including the role of pressure sensors and temperature controls in regulating the compressor's operation.

Areas of Agreement / Disagreement

Participants express differing views on the efficiency of running the AC continuously versus intermittently, and whether the design of the car's AC system influences energy consumption. The discussion remains unresolved with multiple competing perspectives on the best approach.

Contextual Notes

There are limitations regarding the assumptions made about the operation of different car models, the lack of specific data on energy consumption, and the variability in user practices and vehicle designs.

Who May Find This Useful

Individuals interested in automotive engineering, energy efficiency in vehicles, and those seeking to understand the operational mechanics of car air conditioning systems may find this discussion relevant.

  • #31
russ_watters said:
Usually that means there is no AC at all...

I stand corrected. I just went out and took a closer look. There is an AC button. I've been driving the stupid thing for over 3 years and never noticed it before. It must be stuck in the 'on' position, because I've never used it and the AC works when you turn the dial to the blue side.
 
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  • #32
You're probably wasting energy running it in the winter too...
 
  • #33
Quite possibly. At this point, there's no reason to investigate it, though. She's moving up north on the weekend, and is planning to sell it when she gets there.
 
  • #34
russ_watters said:
You're probably wasting energy running it in the winter too...

not true
you have to run the A/C once a month , every month to keep the seals " lubed up "
,,,,90 percent of A/C problems are leaks in the system...
so hit the A/C button once a month for a few minutes to prevent big $$$$ costs
 
  • #35
Ranger Mike said:
not true
you have to run the A/C once a month , every month to keep the seals " lubed up "
,,,,90 percent of A/C problems are leaks in the system...
so hit the A/C button once a month for a few minutes to prevent big $$$$ costs

I've heard this too, but i always forget to turn it on in winter 'cos it's so freaking cold outside. The best way is to use it to demist the inside of the windscreen.
 
  • #36
Ranger Mike said:
not true
you have to run the A/C once a month , every month to keep the seals " lubed up "
,,,,90 percent of A/C problems are leaks in the system...
so hit the A/C button once a month for a few minutes to prevent big $$$$ costs
I've never heard that and it doesn't make any sense to me (I'll check my manual though), but in any case, Danger was apparently running it all the time.
 
  • #37
redargon said:
I've heard this too, but i always forget to turn it on in winter 'cos it's so freaking cold outside. The best way is to use it to demist the inside of the windscreen.
If you turn the AC on, but turn the thermostat all the way up, it will run the compressor and then reheat the air with engine heat. It is actually a good way to warm up a car on a cold day.
 
  • #38
AC has three basic assemblies..compressor, condenser and evaporator.
the compressor is a belt driven " pump" with Electro magnetic clutch assembly..it also has numerous " rubber" O-ring seals...you have many "' rubber " ( ok.. synthetic material now a days) seals...these need to be lubricated to prevent drying out and leaking...the same scenario as storing an automobile over the winter...the biggest problem in storage besides cylinder surface rust is seals drying up...axle seals, transmission drive shaft seals, crankshaft oil seals, master cylinder seals. wheel brake cylinder seals and clutch master cylinder seals is so equipped..and the air conditioner seals...
you got to keep um lubed. Refrigerant like R12 has mineral oil in it and the new EPA crap R134A has PAG oil. both of these oils are to lube the seals and the compressor vanes...
this is why you should run the A/C for 10 minutes EVERY MONTH to keep the seals from hardening..thus leaking..the most common A/C prob is low refrigerant...savvy?
 
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  • #39
I understand the explanation and it seems like it should make sense, I've just never heard it before and don't see why it would be true that the seals would dry out or cylinders would rust.

It just sounds to me like the Seinfeld episode where Jerry has George "exercising the gaskets" on his toilet.
 
  • #40
Good One...That is why you all are so lucky to have a guy like me posting on occasion...

Reminds me of that guy named Chris...who ran into a lot of people saying they understood his explanation but never heard it before and didn't see why it would be true. All he got was a city named after him in Ohio.
 
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