Work on fixed installations (faste installationer) has to be done by an autoriseret elinstallatørvirksomhed (authorised electrical firm). Ask whether they hold the authorisation themselves or bring someone who does, and get that on the invoice.
Vejle lies in a valley, with steep drives and older houses up the hill. That affects scaffolding, delivery of materials, and time on a roof or a facade. The same 4 businesses as the Danish page: AC EL-INSTALLATION A/S, EL-KONSULENTERNE HENRIK BERGHOLT ApS, Kaltoft El, Østjysk El-Teknik ApS.