Insulation is an absolute must. Was yours subsidised by the gov. or is all that finished now?
I have a mainly rammed earth home, so it insulates itself. Don't even need fans on 35+ days. 
Subsidised still, yet the landlord chose the joint that was a dodgy indian company that did mass calling and quoted $200 more than the rebate (so he had to pay out money still)
i was actually keen on the local guy we called ourselfs and he was going to give us a $100 bunnings voucher and be within the rebate, and was a better type of insulation... sad really... again the small local gets pushed out.
and i swear to god they are so stupid the company that rings me all the time...
them: Hello sir, im calling from (can never understand where) i am calling about the government reba.....
Me: stop stop stop, i got insulation installed on Friday I don't need it.
them: yes sir that's good but we are are doing it for free under the government reba.....
Me: i know i have already had it done on Friday.
them: yes sir i understand but we can insulate your home for free.
me: STOP, LISTEN TO ME, i already have insulation it was installed 2 days ago, why the hell( even if it was free) would i want insulation put in AGAIN?
them: ok sir.... do you have any other houses, we are doing the insulation for free under the government re.....
me: oh yeah!
them: yes sir how many houses do you own?
me: right now i have 4, but i will soon have 7... 2 on Strand, 2 on Fleet St and 3 on Trafalgar Square, you know because of the go directly to Trafalgar Square card.. its a gamble but that's my strategy...
them: sorry sir what is the address?
Hangup.