Housing conditions and energy efficiency Households according to whether they have made improvements to thermal insulation or the heating system, by size of the household. Unidades: Horizontal percentages. Has made improvements to thermal insulation or the heating system No improvements have been made and it is warm enough during the cold months No improvements have been made and it is not warm enough during the cold months Total 14,1 60,8 25,1 1 member 12,5 59,2 28,3 2 members 14,5 61,3 24,1 3 members 14,9 61,3 23,8 4 members 15,2 62,7 22,1 5 members or more 14,5 58 27,5 Notas: Fuente: Instituto Nacional de Estadística