^
And that makes it ok does it ? No. It . Doesn't.
I loathe any animal being put into a cage, but that's just my personal take.
You don't show the original cage you bought, but I've attached a pic of one which offers far better ventilation, allows the internals of the cage to remain at room temperature, thus giving hammy a more regulated environment.
Too hot and hammy dehydrates and dies. Plus as pp says, poor ventilation causes condensation, mould, damp, and may affect his bedding and food.
Too cold and hammy will be miserable and suffer again.
did you research before going into all this?
The taped on mesh won't last 2 minutes. Hammy will fast remove/chew the tape and escape.
That storage box home made hamster cage needs to be moved away from the window, and the TV. Imagine that thing blaring out when hammy is trying to live his normal nocturnal life. The volume alone will hurt his ears.
But really, you seem to be impressed with the cost and the 'cool, fancy duct tape' , more than this tiny creatures needs.
was looking at joining stuff up, I have all the tubes from the cage I bought. I never realised how hard it is to cut plastic ...rough cut edges will be so dangerous to this little chap.
Also, plastic is made up of chemicals. Imagine little hammy chewing the stuff, stashing it in his pouches, or possibly/probably swallowing it.
If you can't afford a proper cage, then you can't afford a hamster.
And yes, I'm cross. 
And think of this - if someone imprisoned you into a big, sweaty plastic box that wasn't fit for purpose, what would you think then?