Listed buildings are buildings that have been recognized as having either historic or architectural significance, and they number more than 350,000. These buildings are protected by UK law and require permission from the local planning authority. As for whether you can install our windows in a listed building, this is entirely up to the local planning authority to that you bring the proposed installation. The likelihood of having it approved depends on the grade of the listed building, the purpose of the change, the materials, accessibility, and the impact it will have on the original style of both the building and the windows themselves. Buildings are divided into three grades, Grade I, Grade II* and Grade II: Grade I: These buildings are prestigious, with a high amount of public, cultural and national significance. The craftsmanship of the building is highly acclaimed, and as a result, is protected to a large degree by the government.  Even if the proposed changes are approved, they are likely to come with demands to make them sympathetic to the original vision. Examples of Grade I buildings include Buckingham Palace, the Tower of London, the Royal Bank of Scotland, Hamilton Court etc.  Grade II*: These buildings are regarded with a special interest in the nation, although mostly by the region that its placed in. Examples of Grade II buildings in the UK include Scotland Street School Museum, the Clifton Suspension Bridge and St Pancras Station.  Grade II: These buildings are regarded by a significant portion of people as being special, mostly as a result of their architectural integrity and style. These are the most common type of listed buildings in the UK by far, making up 92% of listed buildings, and can even include residential buildings that people live in. Examples are wide-ranging, from levels of importance as the House of Parliament, to a pair of mills in Cheshire that were converted into flats.  As a general rule, it’s much easier to have a proposed change passed in Grade II* or Grade II building than a Grade I, especially when the energy-efficient new windows replace older, inefficient ones. Overall, one of the most important things to keep in mind when installing these windows in Listed Buildings as historic as Aberdeen is that the aesthetics are not disturbed.