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.
Kolding sits in the Triangle Region, and many firms also cover the neighbouring towns. The motorway is short. Access and scope usually cost more than the distance itself. The same 4 businesses as the Danish page: B. LYHNE VVS ApS, Dall VVS ApS, Kolding VVS ApS, Seirup VVS ApS.