▁It ▁is ▁estimated ▁that ▁the ▁energy ▁consumption ▁can ▁be ▁reduced ▁to ▁ 1 5 0 9 ▁million ▁t onnes ▁of ▁equivalent ▁( M to e ) ▁and ▁at ▁the ▁same ▁time ▁it ▁will ▁cause ▁to ▁reduce ▁the ▁green ▁house ▁g ases ▁production ▁up ▁to ▁ 1 2 . 6 ▁gig at onnes ( G t ) ▁by ▁ 2 0 5 0 . ▁The ▁international ▁energy ▁out look ▁report ▁reve als ▁that ▁the ▁energy ▁consumption ▁is ▁increasing ▁in ▁each ▁year ▁and ▁the ▁energy ▁increment ▁tr ends ▁are ▁shown ▁in ▁fig . ▁ 1 . ▁ ▁So , ▁we ▁conclude ▁that ▁the ▁building ▁sector ▁is ▁one ▁of ▁the ▁largest ▁sector ▁where ▁energy ▁consumption ▁and ▁green ▁house ▁g ases ▁emission ▁can ▁be ▁reduced ▁effectively ▁by ▁impro ving ▁the ▁energy ▁efficiency ▁of ▁buildings ▁and ▁hence ▁H ERS ▁can ▁play ▁a ▁vital ▁role ▁in ▁ach ieving ▁all ▁this . ▁ ▁In ▁different ▁countries ▁ ▁Australia ▁ ▁Five ▁star ▁is ▁the ▁first ▁house - rating ▁scheme ▁of ▁Australia , ▁which ▁was ▁developed ▁in ▁ 1 9 8 0 ▁by ▁the ▁G MI ▁council ▁of ▁Australia . ▁This ▁scheme ▁was ▁basically ▁based ▁on ▁the ▁three ▁basic ▁elements , ▁glass , ▁mass ▁and ▁ins ulation ▁of ▁dwell ing . ▁Due ▁to ▁many ▁limitation ▁this ▁system ▁get ▁failed ▁in ▁att aining ▁popular ity ▁and ▁in ▁ 1 9 9 0 s ▁they ▁develop ▁Victor ian ▁scheme . ▁This ▁scheme ▁att ains ▁some ▁popular ity ▁but ▁it ▁was ▁also ▁not ▁suitable ▁for ▁all ▁climate ▁of ▁Australia . ▁In ▁ 1 9 9