Swedish to English Tech/Engineering Energy / Power Generation

I was under the impression that both of these terms meant the same thing - exhaust or extract air, but now I have a text in which there is a clear difference between them, so any ideas you may have on how to solve this would be greatly appreciated.

Here is the context: "Differensen mellan avluftstemperaturen och frånluftstemperaturen är större än 3°C"

Thanks in advance,

Richard