In connection with the oil crisis in 1974, it was appropriate from a financial point of view to replace  windows with one layer of glass by double-glazed windows. As a result windows with small pane areas were replaced by windows with one large double-glazed pane. This raised discussion as to the changed architectural expression of a large number of buildings. A 3 day conference was held in November 1976 at Byggecentrum in Middelfart Denmark where this issue was discussed along with technical relations to the issue.

The conference resulted in a statement that the business needed a body to take care of the window manufacturer’s interests. Mr Gunnar Madsen, engineer at The Danish Technological Institute offered together with Byggecentrum to assist in establishing such a body. On 17 April 1977 a general assembly was held to establish the association The Danish Windows Manufacturers Cooperation Society (VSO). 16 of the leading Danish manufacturers of standard windows and external doors in wood, plastic and metal respectively, joined the association. A secretariat was established at the Danish Technological Institute in Taastrup, Denmark.

Besides taking care of the interests to the surrounding world as well as colleagues, an important part was added to the VSO objects clause: an obligation to contribute to heightening the quality of Danish windows and doors. An impartial control body  Danish Window Control (Dansk Vindues Kontrol) was then established. However, this body was for VSO members only to whom membership was mandatory.

DVK was managed by a committee consisting of representatives of consumers and window manufacturers but with a majority outside the circle of manufacturers. The main task of the committee was to develop and maintain a standard for the technical requirements to the products as well as laying down the guidelines and supervising 2 annual control visits to the manufacturers.

The requirements for the company and its products were written down in the “DVK Technical regulations for manufacturing windows” or: “DVK Technical regulations”. The guidelines for application to the rules and carry out supervision were described in “DVK Rules”.

DVK and VSO elected a joint secretariat in the department of “Technical Construction” at the Danish Technological Institute where engineer Gunnar Madsen was appointed daily manager. Executing control visits at the manufacturers were carried out in cooperation with Danish Technological Institute in Århus, which led to a long and fruitful cooperation between civil engineer Hans Nielsen and Gunnar Madsen.

Five years after it was established and after a lot of determination and further revision of the “Technical Regulations”, the association had grown from 16 to 30 members consisting of the window manufacturers who at the time were leading nationwide.

In the following years the number of member applications increased significantly but as a result of a section in the Rules of VSO that said that the company at the time of application on average over the last 2 years should have manufactured at least 3000 standard units, only few were eligible to become members.

The rule regarding minimum production was established in order to ensure deliverance of the standard windows and external doors to the consumer from a nationwide company which has proven its worth. The rule, however, resulted in a number of carpenters being excluded from deliveries from their immediate area.

Because of the exclusion of membership at VSO, smaller window manufacturers established FDV (Foreningen af Danske Vinduesproducenter) FDV and KVY (Kontrolordningen for Vinduer og Yderdøre) with the aid of their organizations.

Denmark now had 2 organizations who worked at the same purpose: to heighten the quality of windows and external doors. FDV and KVY established a secretariat at Danish Technological Institute in Jutland with Civil engineer Hans Nielsen as secretary.

Shortly after establishing the organization, FDV/KVY has 70 members while VSO/DVK had 38 members.

The two associations each continued developing their members but to the consumers it became increasingly incomprehensible dealing with two associations who had the same purpose. It was therefore a good opportunity to discuss a potential merger when EU in 1990 in connection with establishing the Internal Market required that all products were to carry the CE mark on the basis of tests carried out in accordance with the harmonized standards.

In 1992 the two associations merged and continued as VSO (The Association of Danish Windows Manufacturers) and DVK (Danish Windows Control). At the same time it was agreed to change DVK to an accredited certification body under the supervision of DANAK (Danish Accreditation and Metrology Fund) who on behalf of the state, supervise the impartial test and certifying bodies.

One condition for accrediting on the basis of the European standard for certification bodies is that there can be no close relations between an association and the certification body. For this reason DVK was separated from VSO who left it to Danish Technological Institute to establish and run a certification body named DVC (Danish Window Certification).

In connection with establishing DVC, the joint secretariat for VSO and DVK was divided as well. Civil engineer Hans Nielsen took over the secretariat for VSO and was responsible for the contents of the Technical requirements for manufacturing windows and external doors. Engineer Gunnar Madsen became daily leader and head of department at DVC.

After an extensive editing of the Technical Requirements and establishing a quality control system for DVC in accordance with DS/EN 45011, DVC was in 1994 accredited by DANAK (Danish Accreditation and Metrology Fund) to certify the rules for windows and external doors with the VSO “Technical Requirements” as well as certifying the rules of quality control systems in accordance with ISO 9000.

After the merger between the Association of Danish Window Manufacturers (FDV) and VSO, 48 companies were associated with VSO, while 120 companies were associated with FDV. After tightened requirements to the quality control of the companies and to the product quality itself, a number of small companies dropped out when converting DVK to DVC. In 1997, 106 companies were then able to DVC-brand their production of windows and external doors in wood, wood/aluminium, plastic and metal respectively.

From VSO (The Danish Windows Manufactures Cooperation Society) to VI (The Association of Danish Window Manufacturers)

One of the differences between the Association of Danish Window Manufacturers (FDV) and VSO was that FDV from the beginning and until the merger had a warranty scheme which came into effect if a member could not or would not acknowledge a financial claim in connection with a complaint.

A few years after the merger a large number of the VSO members wanted to re-establish a warranty scheme. But before VSO managed to establish such an agreement, BYG (Byggeriets Arbejdsgivere), who organised approximately ¾ of the VSO members, offered that they at no extra cost could be attached to BYG’s warranty scheme for carpenters.

Danish Industry established a similar agreement for its window manufacturers. Those VSO members who were not organized at BYG or DI respectively, were left without a warranty scheme. This meant that more members dropped out and in 2003/2004 – when Mr Hans Nielsen and Mr Gunnar Madsen retired – VSO had only 70 members.

The Board of Directors of VSO then decided a new strategy and action plan. The first step was to establish an independent secretariat without connection to Danish Technological Institute and employing Engineer Mr Johny H. Jensen as VSO Director as of 1 January 2004.

The next step was taken in April 2005, when the association changed its name to VinduesIndustrien (The Association of Danish Window Manufacturers) with a new logo. The 28 year old association was then upgraded to a modernized organization known for manufacturing high quality windows and external doors.

DVV label which is attached to the Technical Requirements shall be from 1 January 2012 to signal:

• the establishment has been certified by an independent body accredited by DANAK.

• the corporate elements meet the requirements as specified in the Technical Requirements.

• the corporate elements comply with current legislation in Denmark.

• the corporate elements have a valid CE marking.

• to companies connected to an appeals board for the treatment of any complaints.

• to companies connected to a 5 year guarantee against defects.

The DVV-mark will signal an integrated, consumer-proof quality system for windows and doors in Denmark.

The WindowIndustry will in the future market the new DVV-label.

See DVV-brochure here (pdf)

August 1, 2011

In 2018, The Building Quality Control Board (Byggeriets Kvalitetskontrol A/S) achieved accreditation as a certification body for DVV.

This meant that there were now two independent certification bodies, both accredited by DANAK, and which were certified in accordance with the Technical Requirements for DVV.

The two certification bodies were:

• Byggeriets Kvalitetskontrol A/S
• Dancert A/S

In the summer of 2019, Dancert A/S announced that they would soon cease to offer certification accordingly the quality standard Technical Requirements for DVV.

As the owner of the quality standard, the Board of directors of VinduesIndustrien firmly believed that the successful DVV scheme will of course continue - but as a consequence of the announcement now during a period of time with only one certification body.

Thus, from  April 1st 2020, only the Byggeriets Kvalitetskontrol A/S is authorized to certify under the Technical Requirements for DVV.

However, it remains the intention of the Association of Danish Window Manufacturers (VinduesIndustrien) to increase the DVV certification among several certification bodies, so as to provide companies with choice and a competitive price.

In March 2023, the general assembly unanimously decided that the association will henceforth be a part of the Confederation of Danish Industry. The association is placed as an independent association within DI Byggeri.