Ah sorry Mcririck, I had not realised you had a later vehicle where all the controls are on the tea tray, on earlier cars with a proper dashboard there is a button on the Climatronic marked ECON or on a simple Climatic equipped car like mine there is an AC on/off switch. In either case it does not switch the AC off 100% but it will not be sapping any significant power, just stirring the refrigerant around the system.

 

My post on Saturday was not appropriate and in hindsight very abrupt, had you had an ECON button you would have understood.

On 28/10/2023 at 15:39, Kenny R said:

Think you’ll find modern ac systems only have a marginal effect on fuel economy.

With every car I’ve had with climate control I’ve set the temp at 20° ac on and auto and never had the need to touch the control again.

The benefit being at a comfortable temp, and no steamed up windows in the cooler months far outweigh the minimal amount of fuel used.

same as above, have done this for years in my auto AC cars, no foggy windows etc, nice comfortable temp inside, not worth worrying about fuel for the cost of it

This last week I noticed my mpg was quite a bit lower than usual. Yesterday I checked the AC and decided to turn it off. mpg much better these last two days.

And how do you explain the high consumption only manifesting in the last week with low temperatures where the aircon barely has any work to do?

 

It will consume more if the regrigerant charge is low but only measurably so in stinking hot weather.

7 hours ago, J.R. said:

And how do you explain the high consumption only manifesting in the last week with low temperatures where the aircon barely has any work to do?

 

It will consume more if the regrigerant charge is low but only measurably so in stinking hot weather.

The last week wasn't as cold here as previous weeks.

I don't think I had the Aircon symbol lit up in previous weeks.

The regen charge is pretty consistent and I understand how it works.

Regen charge? Is that not the regenerative braking system that supposedly gives your vehicle better fuel consumption? I was referring to the charge of refrigerant gas in the air conditioning system. You would not know that it is "pretty consistent" without regularly checking the high and low pressures with a manifold test and comparing them to the tables, although it should be consistent, the charge (weight) would not vary day to day, the system pressure does according to temperature and humidity.

6 minutes ago, J.R. said:

Regen charge? Is that not the regenerative braking system that supposedly gives your vehicle better fuel consumption? I was referring to the charge of refrigerant gas in the air conditioning system. You would not know that it is "pretty consistent" without regularly checking the high and low pressures with a manifold test and comparing them to the tables, although it should be consistent, the charge (weight) would not vary day to day, the system pressure does according to temperature and humidity.

I'm not sure why that would affect fuel consumption so drastically, why even mention it? The car is 2 months old. You seem very resistant to the idea that AC affects fuel consumption.

Edited 16 December, 20232 yr by mccririck

1 hour ago, mccririck said:

why even mention it

 

I didn't, you did! I thought perhaps it was a typo:

 

5 hours ago, mccririck said:

The regen charge is pretty consistent and I understand how it works.

 

 

1 hour ago, mccririck said:

You seem very resistant to the idea that AC affects fuel consumption.

 

 

Not at all, the first law of thermodynamics is irrefutable, I simply explained that unless your system was low on refrigenant charge you would not notice the de minimus consumption other than in the height of summer in a hot region, certainly not now in the UK.

 

I understand and am experienced with vehicle and domestic AC systems, I made it my business to do so and have invested in the test equipment, vacuum pumps and gases, I was encouraging you to have your system charge checked if you believe that it is noticeably reducing your fuel economy in the current cold weather.

 

You can lead a horse to water.........................................

@mccriricki am not sure that the AC is affecting the MPG of the 1.4 TSI when on, it might be more affecting what you are looking at on the display for Average MPG.

 

The AC was not in operation when the Ambient temp was at 3*oC or below even if a little light showed it was.

 

If the PHEV has the engine fired up and using more petrol enough to bother you with AC on then do just switch it off if that does not mean the windows are fogging up and the damp / moisture is getting retained in the car. 

On 16/12/2023 at 12:59, Rooted said:

@mccriricki am not sure that the AC is affecting the MPG of the 1.4 TSI when on, it might be more affecting what you are looking at on the display for Average MPG.

 

The AC was not in operation when the Ambient temp was at 3*oC or below even if a little light showed it was.

 

If the PHEV has the engine fired up and using more petrol enough to bother you with AC on then do just switch it off if that does not mean the windows are fogging up and the damp / moisture is getting retained in the car. 

I only use the can in hybrid mode at the moment, I haven't been charging it myself, so stored electric doesn't tend to go above 3 miles worth.

 

Why do you mention it not having any effect below 3⁰C? The week I was focusing on was above that btw.

 

Why would AC not affect mpg? It has to as it uses energy. 

Cooling engines / coolant oil in Summer also uses energy,

and heating this up like oil and coolant, and hybrid,s ICE engines firing up need to get to efficient temps each time they fire up, then shut down, then again fire up.

Unlike an ICE vehicle that might warm up and stay warmed up until the journey ends.

 

The reason i mention the AC not operating at 3*oC and below is because i read owners manuals and know the system,s and how the work.

Some are 4 *oC and below and some 2*oC and below.

 

As to why the AC does not greatly affect the MPG is because it is such a small amount compared to other factors.

Tyres / Pressures, Catalytic converter needing up to temp on cold starts and now the GPF needing up to heat and then how much you might use stop / start or not and wipers, lights., entertainment and all the rest. 

Edited 17 December, 20232 yr by Rooted

I used to drive with AC off in all but very hot conditions as I prefer fresh air, including open window. I worked out after years of doing this that the AC systems in my cars were suffering by only sporadic or seasonal use and required compressor servicing & regassing too often for my liking. In my last two cars I started leaving climate/AC on full time and it had no measurable impact on fuel economy. In the current Octavia I leave it on a set temp and I'm returning equal or better consumption figures than Skoda claim. Happy days. Nothing to be saved by turning AC off, and I still have a window / roof open occasionally (naughty, I know ). Petrol only, no hybrid/electric/battery etc. in my little cruiser.