I have insulation in the roof courtesy of the Rudd Labor government. It has certainly kept the house cooler in summer.
However in winter the situation is worse, before the insulation the sun shining on the metal roof heated the place beautifully, the house was just right about 10am and stayed warm the whole day. Since the insulation was installed the place doesn’t warm up in winter unless you open all the doors and windows to let the heat in.
It has been about 23/24C in our lounge every evening this week even at 9 pm. That is with no heat on but we’ve had lovely weather this week and our house is a sun magnet. We have big patio doors which take up half of the length of the room out to the south facing garden so it retains the heat of the sun for the rest of the day.
I feel so sorry for people whose homes don’t get much sun as it makes a huge difference. A neighbour of mine gets no sun in any room in her cottage and she comes to mine and asks if I have the heat on! 
