Okay, to be honest, this is mainly true in the summer when greened areas on the house prevent sun exposure to the building, reducing heat in the home. Thermal insulation in the winter and reduction in heating costs is really only likely in buildings thickly covered on all sides with ivy.
t3://page?uid=2601We usually think of thermal insulation as our friend during cold winters, providing insulating layers to keep our house warm and reduce heating costs. But insulation is also needed in the summer when walls and interiors heat up excessively in strong sunlight. Plant life on the facade acts as a natural insulator, absorbing the sun's rays before they reach the facade. This is especially true in non-insulated homes where the greening can replace air conditioning and save expenses. Facade cooling with plants saves electricity costs and contributes actively to climate protection! The following climbing plants are suitable: the ornamental vines “Boston Ivy”, “Dark Green”, “Engelmannii”, “Inserta”, the virginia creeper, the crimson glory vine, wild grapevine, grape vine, climbing hydrangea and wisteria.
Summer AND winter cost savings are only possible with walls on which ivy or Irish ivy grows and develops its ageing form “Arborescens”, which creates leaf cushions that protrude far forwards. However, this ‘thickening’ of the façade can lead to the ‘embrasure’ effect at the windows, where the unobstructed view to the outside is severely impaired. The savings will be a maximum of 5 - 10 % of the heating costs. In addition, there must be no wind to carry away the protective air cushion built up in the foliage... In northern Germany, near the North Sea and Baltic coasts, houses completely covered in ivy have a long tradition!
In southern Germany and Europe, star jasmine is also an option, also the evergreen honeysuckle.