Work on fixed water and heating installations needs an autoriseret VVS-installatør (authorised plumbing contractor), or a firm that brings one. Ask which it is, and ask for that on the invoice (faktura). Authorisations are looked up at Sikkerhedsstyrelsen, sik.dk.
Esbjerg is more houses and industry than tight apartment blocks. Wind on the west coast affects roofs, facades and outdoor work more than in eastern Denmark. The same 4 businesses as the Danish page: Breinholt VVS ApS, FORUM SMEDE OG VVS ApS, Ribe VVS ApS, Star VVS Entreprise A/S.