In Addition to Glazing, Its Necessary to Make Insulation, You Canstall a Warm Floor and Install Radiators. It will be good if it is to spend water to your Future Winter Garden. Do Ventilation, But the SHOULD Not Be Drafts. If the Balcony Comes Out, On the Sunny String, You Will Have to Close The Foliage from Bright Sunlight In Weather to Prevent Overheating.