you might have a large heat sources inside your house:
1) oven often on. 2) lots of fridges with poor door insulation. 3) lots of PC's/monitors/plasmas left on.
or:
- it could be the sun coming in through the windows and heating the floor. - it could be the sun heating the walls (if thin - eg wood)
Best is to: isolate heat sources (close doors to kitchen etc. prevent sunlight coming through the windows. Keep sunlight off the walls withe eaves/tree planting etc.
But most importantly the house will no longer radiate heat overnight, so the prior days heat will be stored and added to by the fridge etc overnight.
So cool the house overnight with open windows and close them early in the morning.
A small aircon (with heat exchanger outside) might make all the difference now you are insulated, but will only work if you don't have alot of glass to which isn't a good insulator..
