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collir tua 40 y cant o wres drwy waliau sydd heb eu hinsiwleiddio , collir 20 y cant drwy awyru , a chollir 20 y cant ar ben hynny drwy ffenestri sydd wedi'u hinsiwleiddio'n wael
some 40 per cent of heat is lost through uninsulated walls , 20 per cent is lost through ventilation , and a further 20 per cent is lost through poorly insulated windows
mae bron 1 .3 miliwn o dai yng nghymru , y mae 19 y cant , neu 240 ,000 , ohonynt wedi'u dynodi'n swyddogol yn rhai sy'n anaddas a heb eu hinsiwleiddio
there are almost 1 .3 million houses in wales , 19 per cent , or 240 ,000 , of which are officially classified as unfit and lacking insulation