[Marty mii]

Anybody tested if running with the air con on makes any difference to mpg?

 

[Collas]

Of course it will, though it's not that much. If you don't exercise the air con on a regular basis then the system will stop working, which is expensive to repair.

Nick

 

[_1S_]

Anybody tested if running with the air con on makes any difference to mpg?

In my experience, it depends on where you use your up!

When used in town, or in driving situations where you often accelerate, having AC on makes a big difference. With the hot weather last week, I've seen it getting as bad as a 30% increase (as indicated on the on-board computer) in those conditions.
The AC was on at full blast with the 30-34 °C weather though.

Once out on the Motorway / open road, things settled down again, and the overall tank returned average fuel consumption.Edited by: _1S_

 

[Rickenbacker]

Obviously recently I've had the air con on almost all of the time and I check my mpg every fill up. I haven't noticed any difference, in fact my UP seems to get slightly better mpg in the warmer months even with air con on. I'm still averaging 55mpg consistently but in winter this was more like 50mpg.

 

[_1S_]

my UP seems to get slightly better mpg in the warmer months even with air con on.

With the warmer air you get less air resistance. Petrol engines generally like warmer intake air too, and they obviously warm up quicker, which all helps to reduce fuel consumption. So you can still get better fuel consumption despite running the AC .

On the CNG up, you can really feel the power drain from using the AC.
Acceleration is even slower and takes more fuel, while idle fuel use is doubled to 0.8kg/h with AC on.

The roads I've taken with the AC on full tilt, would normally take 3.0 to 3.2 kg/100km (indicated) without AC. They now took 4.6 !
The math kind of fits though.
Using like 0.5h to do around 25km, would add 0.4 kg to 25km, or 1.6kg to 100 km.


Only one solution : drive faster with the AC on

 

[move up!]

-IS-, could you tell us how much CNG costs per Kg (or litre), please? Of course, we don't have it in the UK yet, but I'm just interested...