Who understands, please give advice. Can it be that the cold from the …

Who understands, please give advice. Can it be that the cold from the balcony being removed on the first floor is felt? Should these holes be closed? Seal them with cement? Friends of the hostess said that these holes cannot carry cold into the house....but I feel how cold it is at night... My little child... and then winter comes... And if it blows, then it will be impossible to solve it later... It's only in summer... Nobody has lived in our house for a long time... Therefore they can't know for sure. I am very worried about what to do... Please give advice who understands this.