Is Carbon filter and fans needed for 3x3x6 grow tent, but placed outside

So I'm planning putting my grow tent outside in a small shed, the tent should just fit inside the shed. The shed door will constantly be open to circulate, I have a 400w hps. If I can manage to keep the temp around 20c - 25c (that's around 65 - 75 farenheit) is it worth spending another $200 for the ducting and carbon filter when I could just keep the shed and tent door open. I live in Australia right down the bottom, so it can get quite cold in winter (which is a month away) temps can drop to around -1. So would the climate around here be good enough to not have to invest in these items? Any help much appreciated

The filter isnt for the envirotment
The filter stops the smells
The filter stops the cops and friends finding it.
Chop day 1 small pla t will stink the whole block out . No filter

The sun in ur country will dsmn grow year round compared to uk lol. Aslong as its 15degree min nighttime ul grow good. Strain dependant some dont mind cold bread for uk etc

Autos in winter.
Id love a sun grow in aus all that uv n shit hot days man.

Grow out in sumne4 tent winter if it does get cold. But i seen peeps gro uk in the cold so

But sheds get damn hot u know?