Auto climate control

[Downsizer]

My car is parked in the sun and in the last few days the cabin temperature when parked reaches around 25 C. I have the climate control set to 21C and auto and in these conditions it starts up in recirculating mode with air-conditioning and high fan speed although the external air temperature is only about 17C. It seems to me to be more economical to turn the recirculation off and use the external air to cool the cabin, or am I missing something?

[Marco1979]

The sensor measuring outdoor temperature may also show 25-ish values when parked. At some point it will balance out and turn airconditioning off.
I find the best option to leave the whole system off for the first minute and just open some windows. Works like a charm . Also prevents the engine from starting up.

[Downsizer]

Thanks. Opening windows - what a good idea!

[coldstart]

Thanks. Opening windows - what a good idea!

hmm, it's even in the manual (section "Using automatic climate control"):

If the interior is very warm, you can cool it down more rapidly by partially opening the windows, turning the system on auto, and setting the temperature to low. Change the fresh air mode to recirculation mode until the temperature cools down.

[Downsizer]

Thanks for pointing that out. If I’ld used my feeble wits I would have opened the window as well as turning off recirculation. And Marco above has explained why the system did not recognise that the outside temperature was a lot lower.

[Kremmen]

The outside temp sensor is somewhere behind the front bumper so if you've parked nose into the sun then .....

[Downsizer]

Yes, I usually park facing south. I could park the other way but it would then be close to a south facing high wall which also gets quite warm. Opening the window for a few minutes is the best solution!

[Kremmen]

I always found just leave it on auto and let it do its thing

Honda aircon isn't the best and in summer on hot days I dropped the selected temp to 19 which seemed to do the trick and dropped the temp to 21 ish, eventually. Setting 21 and the temp never got below 24

On my previous Lexus IS200 and Xantias, if I selected 21 then it went down to 21, and quite quickly as the fan gave it some till it got there. All read from an accurate internal digital thermo I had. Positioned out of sun and car airflow

Honda system (3 Civics and the Jazz) seems weak and gives up early. Maybe down to striving for better economy figures

[Jazzik]

Thanks. Opening windows - what a good idea!

...and the best surprise is: you don't have to get into that hot car to open the windows... You can do it remotely with the key fob! See page 186 of the manual:
https://www.honda.co.uk/cars/owners/manuals-and-guides/honda-owners-manuals/_jcr_content/par1/textcolumnwithimagem_1653971839/textColumn/richtextdownload_90f/file.res/2021%20Jazz%20Owner%60s%20Manual.pdf

Here our Neil shows how to close all windows, by using the unlock button you open them: