Roof insulation - what to look for
You can usually get access to your roof space through a ceiling hatch, either in the hall or living room (if not there, check in the bedroom wardrobes). If you have a ceiling hatch, safely peer into the roof space from a ladder and assess whether you have any insulation present. Take a tape measure with you and measure how thick it is.
Some homes do not have a ceiling hatch, either because one hasn't been installed or, more commonly, because the roof is a skillion or cathedral roof. Skillion and cathedral roofs are commonly pitched roofs in which the sloping roof is seen from the inside of the house as well as the outside. This means there is no large ceiling cavity.
Roofs without ceiling access should be assumed to be insulated if they were built after 1978. Any inaccessible roofs built before this date probably don't have any insulation.