Why ventilation is more important than insulation
Insulation is exactly that an insulator, It will insulate whatever is in the home.
If you create heat it will help the heat last longer, if you cool it will stop the home radiating the suns energy into the home during the day making it easier to cool.
Insulation will also trap moisture & odours VOC's which will lead to allergic reactions bacteria & dangerous mould if you don't manage the above.
During the warm-up program where many state houses and welfare dependent people got free insulation a lot of the homes developed black mould in the bedrooms & living areas. This lead to lung and other respiratory illnesses as mould will enter the airways & attach itself to the inside of your lung causing that dry cough & can lead to very serious infections & allergies.
Ventilation uses the free dry air from your roof cavity which is filtered then pushed into the home flushing out odours, moisture VOC's all day, it's a bit like folding your home inside out & putting it on the line on a nice day every day.
This means every time you or mother nature puts moisture into the home the filtered dry air will remove it so you can manage the health of your home all day every day.
This is when insulation is at it's best as the dryer home will have a warmer core temperature naturally and the insulation will help you get better efficiency from your heating & cooling.
It's a myth that insulation can dry your home or keep it dry as it cannot remove internal moisture & the same is true about heating your home.
Ventilation also can not heat & cool your home but with both ventilation & insulation it is cheaper & easier to heat & cools your home.