Originally Posted by Deejay
Originally Posted by MOG42
Really appreciate the time taken in your post and a few interesting points. As you say there is a fair bit about - which doesn't seem to e moving very quickly - perhaps another story! I felt the zircon would only really be useful with the windows in and the roof up - but it seems it's better than that! Thanks once again will report back Dave
Running air-con with roof down may feel nice to some degree (note, fan on full, nozzles directed towards you, etc) but it is working really hard. The compressor never gets to cycle on and off, the air filters are filtering much more air than normal and so will clog up quicker and of course, as mentioned, fuel consumption will dive.
On a hot day at home, would you open the freezer door and spend a couple of hours sitting in front of it to cool down?
In extremely hot weather, I find it more effective to pop the hood up with windows removed. Less chance of sunburn too.

Morning Doug, I agree that the aircon is much much more efficient in feel with roof up. However, I did undertake a test on our cars aircon last year regarding compressor cycle periods with the roof up and down. I found it only cycles slightly faster when roof is up, it does not run continuously. I did not expect this, but I have checked this year also and its the same, I can only assume its where the AC run sensor is located on the car?. Note: The only reason I check the aircon each year is because we had so many issues with it after purchase, I half expect it not to work, but since the systems seals were changed its been fine. Also, at very slow speeds in traffic you can hear the compressor cycling, but its also possible to feel it in the air flow as there is a slight variation in temp as it cycles.

Dave
Plus Six "Squeak"
Roadster departed.
1936 BSA Empire Star Q8. 1935 BSA W7-35. 1938 BSA M20