The building industry in general and the housing industry in Western Europe in particular are facing a turning-point. At first glance, this turning-point does not seem too remarkable; definitely not from a safe vantage point of 500 kilometres away. The announcement that, as of 1 January 2013, gas boilers may no longer be sold in Denmark is of great importance for the building industry and installations technology. It heralds a new era of thinking about the different forms of energy, and thus exergy as well. The background behind this radical decision is to avoid burning a resource as valuable as natural gas at 1200° Celsius to achieve temperatures of 20° Celsius in our homes. In Denmark, process heat for low caloric heating is seen as an unwise and unnecessary exploitation. The functional lifespan of a gas boiler is approximately 12 years, thus it will take ten years before the gas flame goes out in Danish houses, and the transition to district heating and sustainable energy will be carried out on a large scale.

In the Netherlands, the only sustainable source of energy is the sun; a large nuclear fusion reactor at a safe distance of 149 million kilometres away. Fossil energy is the raw material for upcoming generations. From a technical point of view, we have been able to build minimum energy dwellings for thirty years. Now we are witness to a completed self-sufficient dwelling, the Concept House Delft Prototype at Heijplaat in Rotterdam. Here, on the other side of the Nieuwe Waterweg on Woudhoek Noord 184 minimum energy dwellings were built in 1980–1982. During the designing phase, the architect of these flats, Jón Kristinsson, discovered that the then common two pilot flames in the kitchen geyser – practically a second heating device – consumed half of the gas that the new energy efficient apartments required. Thus, electronic ignition was devised. Since then, gas appliances with pilot flame are no longer available in the Netherlands. We live in the land of the Gasunie (gas union); thus things will not continue at that speed. But changes are coming. We can drastically reduce the heating demand of new and existing dwellings by handling ventilation intelligently, based on CO₂ inside air quality measurements. And most importantly, by switching to very low temperature heating. Solar energy and waste heat in the industry and cooling water in electric power plants is low temperature water, albeit with seasonal heat storage in the ground.

The electric heat pumps that, in the Netherlands, will replace the gas boilers have a useful yield (COP) of 3 to 4. At very low temperatures the yield can increase to 8 to 10, i.e. twice as much. The new coal plant on the Maasvlakte has a yield of 40 to 45%, the remaining 55 to 60% of the thermal energy either goes into the air or to the North Sea as valuable cooling-water; but it does not contribute to district heating.

A sustainable society is very comprehensive, and energy is an important subject that requires solutions. My definition of sustainability is short and simple: ‘Anything that future generations would like to inherit and use and are able to maintain is sustainable’.

The long history of the recently completed concept house Delft prototype, in ‘Het Nieuwe Dorp’ of the workers district Heijplaat next to the former RDM dry-dock terrain in Rotterdam, which at presence undergoes a transformation into a sustainable knowledge and innovation campus, is invisible. At the time of completion, this energy positive experiment is a snapshot of the ‘state of the art’ in 2012 of sustainable, stacked industrial wood skeleton construction in the Netherlands; based on existing and relatively affordable technology. The innovation lies in the way that these technologies are industrialised, developed, integrated and realised in a process of close cooperation and adjustment between various industry partners and academic researchers. The initiative of the underlying academic research originated in 2005 from Harry Oude Vrielink, a retired contractor in Vriezenveen. What is to be commended is how high the bar has been set for this difficult task that designers, producers and researchers have taken upon them to find integral solutions for all the problems of self-sustained industrial building. In spite of financial adversities and administrative meanderings, and with some delay, a habitable prototype has been realised. General Dwight D. Eisenhower supported the view “The process of working together on a solution is more important than the solution”. Since 2005, two of the main academic scientific staff members of the long process concept house have also been appointed professors. Thus, the acquired knowledge is certainly heard and spread at the two technical universities.

Time will tell in how far super-components such as the sanitary unit, preassembled ducting channels with connected installations and home automation devices will be considered and applied in the future renovation of residential dwellings in the Netherlands. “Predictions are difficult, particularly as far as the future is concerned”, Dutch cabaret artist Wim Kan once said. My prediction is that from an architectural point of view the concept house Prototype will remain unchanged for a while, but the installations and execution of the energy concept will be caught up with. Luckily the concept is developed as a ‘plug and play’ system which anticipates such a development. It seems plausible that in a few years time, for renovation projects, very low temperature air heating will appear in addition to underfloor heating. Unfortunately, this is one of only a few highlights without governmental political visions about renovation that allow Dutch voters to keep warm in the future, even without natural gas.

It is also to be expected that intelligent decentralised balanced ventilation in residential dwellings is easier to install than today's central ventilation with air ducts. The concept house Prototype, the ambitious pilot project of the Concept House Urban Villa, and the simultaneously conducted zero series developments (with several ongoing initiatives) should be able to accommodate such transformations of subsystems without abandoning the core of the concept. It is also precisely this flexibility for change, together with addressing the urgent task, the (new) necessity along the path of integral design as well as building and maintaining the buildings over the entire time of use, and even the unavoidable end of life that forms the power of this concept. It forms the basis for the correct effect of sustainability in the sense of perseverance.

In short: All praise for the initiative, the persistence and the final result of the concept house Delft prototype, which will prove its service.

Jón Kristinsson

Emeritus Professor Environmental Design TU Delft, architect and inventor. [Kristinsson, 1991, 2001, 2006, 2012]