Building without heating: more material or more installations?

Last month I finally visited the ‘2226’ office in Austria near Bregenz. (updated in 2022 and 2024, see at the end) . The building, realized about 4 years ago, already won many prizes. What is special about this building: it has no heating system, and in fact no ventilation system, except windows that can be opened. When I first heard this, I was immediately focused. After all, we mainly try to get a buildings operational energy  under control with the addition of a lot of high-tech. And as I experienced, with 0-energy buildings the amount of technology is even more increasing. Technology which itself also requires materials and energy. So what has happened here?

The architectural office, Baumschleger-Eberle, was already known for its progressive buildings, but this was the superlative. [1] To make the g function without heating took a lot of calculating time. To find a combination of mass, insulation and internal heat sources, which, calculated over the year, ensure that the inside temperature remains between 22 and 26 degrees. Ventilation is regulated via panels next to the windows, which open on the basis of CO2 measurements, and possibly provide night cooling in the summer. The building eventually became a cube with sides of 24 meters, high ceilings and vertical , high windows. The walls are approximately 80 cm thick, made of ceramic elements, half of that insulated elements.

And it works, after 4 years of measuring, there are no significant problems, and the people in the building are satisfied. Knowing this, you would expect this to become the standard way of building, but the customers are not lining up, a staff member told me. Potential customers doubt and hesitate, though a few ‘clones’ are now under construction.

I already had such an ‘aha’ experience once before: when I discovered that, in terms of energy and material combined  load,  the best solution for a 0-energy retrofit of a terraced house turned out to be  limited insulation , only the cavity walls, while adding some more PV panels [2] Because the material impact was the deciding factor for a home that did not require fossil operational energy. Annoying, because at that time I was just involved in a project where we did insulate heavily to passive house level to limit the amount of solar panels.

And this was a similar ‘aha erlebnis’, but in the other direction: using more material, in the façade, that is extra load, but doing so  you suddenly make another heavy load superfluous, that of a heating installation and required solar panels for this.

How about that? How does that outweigh each other?

Then we just have to dig deeper into the numbers. But data for material comparison is difficult to get, especially with regard to the impact of installations.. For the embodied impact of the materials for installations, for example, very few data are available,  and there is not much to be found in the databases either. But I knew a project from an IEA research group on embodied energy * for which it had been calculated: a demonstration office for the Deutsche Umwelt Bundesambt, well documented, in Berlin. [3] Incidentally also a zero energy office with regard to building-related energy.

And those figures show that the embodied energy from installations accounts for no less than 25% of the total embodied energy, and even 40% of the CO2 emissions. That is quite substantial, in absolute numbers the EE is 2.7 GJ / m2 floor (for the installations). The building as a whole comes out at 10 GJ / m2 of useful floor space. [4] That is well above average, most common buildings are around 5-6 GJ / m2 floor, excluding installations or so. It is, of course, only a single measurement, but it makes you think, if that is the general trend for more 0-energy buildings, then that would be a considerable extra burden on buildings.

But what about this, compared to 2226? Well, we also have the figures for that building, again thanks to research in an IEA research group (EBC Annex 72, the successor to the A57 group [5]). Which results in a total Embodied energy of 5.6 GJ / m2. And that is interesting: This office (including ‘installations’, which are therefore not there …) has a much lower embodied energy as the extra-active 0-energy office in Berlin  And despite the increased use of materials, the EE value is even not above an average value for buildings, buildings that are not even zero energy.

The question that remains, and is important, is how many materials have been used for this extra-passive office? Because facades of more than 80 cm and high ceilings are not natural. And that amounts to more than 1900 kg per m2. Which is a lot, if you know that an average building in the Netherlands is somewhere between 1000 and 1200 kg / m2. And that building in wood construction  could even reduce that towards 600 kg / m2.

The environmental impact in the sense of invested energy is not that high, the embodied energy EE, but the material input itself, the claim on raw materials is high. It is of course mainly ceramic material, which is not the most ‘endangered material’. In principle it is erosion materials coming down from mountains via rivers, as such renewable but there is a limit to everything. In large parts of North China, it is forbidden to build with ceramic products, because the demand became such large that fertile agricultural land was used for it. There is even a limit to ceramics as a raw material. Which does not imply that we cannot use it: If 2226 is an example of a building with the lowest combined operational and embodied energy impact (OE and EE), then we have to build like that.. It just implies that we can construct a limited number of new buildings only, just as much as to be able to stay within the natural limits of the material flow,  adapt to the speed of regeneration of this basically renewable raw material. It is a matter of evaluating the building level as well as at the level of resource flows. One cannot do without the other. [6]


However, is this a 0-energy building? If we ignore the low energy for the ventilation control next to the windows, in fact it is, as far as building-related energy consumption is concerned. Despite the fact that it didn’t even have solar panels on delivery. After inquirinis the reson for that was a subsidy issue, the roof will soon also have solar panels. Which then primarily covers “household consumption”, there si nothing else….

This domestic use is therefore in fact the ‘heating load’, as an internal source. This is around 54 kWh / m2a for this office. And supplemented with a small amount of internal heat from the working people. (But in calculations, we do not have to include that 54 kWh/m2  as heating demand: for buildings with a heating we also do not add the internal heat sources to the heat demand. Instead, we subtract that to come to the real demand..)

And then a  key question: what is the climate-neutral year for this building? [7] The year that not only the operational energy is 0, but also the Embodied energy is compensated, or the total net is Zero Emission Building. Or a net 0 NEG.

Although it is an (almost) zero energy building with regard to building-related operational energy, the construction and materials have of course caused a CO2 impact. When will it be compensated? As the building does not generate active renewable energy (until now), this embodied energy is not compensated. So there remains a embodied energy burden, a considerable direct CO2 contribution. And that is direct, during construction, not spread over the lifetime of the building!.

Assuming that solar panels will be installed soon, and suppose that is 400 m2 of the roof, that whole building-related energy production can be seen as compensation for materials production. With a yield of 400x 140 kWh, it is a total of 56000 kWh / year. Or 23.5 kWh / m2a. If we divide embodied energy, by that amount,  it takes 66 years. (plus 3 years for the EE of the solar panels) to compensate.. The building will be net climate neutral in 2088. That is far too late, if we want to be close to 0-CO2 emissions by 2050, because of the Paris climate treaty. Buildings should be climate neutral well before 2050. Again a signal that we must be economical with new constructions, no matter how well designed ……..

In that respect, there is another special aspect of this building: This building needs solar radiation in its year-round heat balance, so it is important to avoid a neighbouring building that casts a shadow on this building. Just as this building itself should not cast a shadow on its neighbors, to give the other building the opportunity to implement such a concept as well.. In other words: urban planning will have to adapt to guaranteeing that solar radiation access !



addendum 051222 and [11] :

a more extensive and recent article, written for students and in english , can be downloaded here:
and recent research on application of 2226 concept in other climate zones, can be found in this publication:
more buildings have since been completed, as well as housing wihout heating  (‘2226 in Graf’), see several collected links under [11]

add 200324:

Two interesting lessons from the successful building concept ‘2226’, the offices and homes without heating system, by Baumschlager-Eberle, in Austria. [x] . Thereby, ventilation regime is important, (via self-opening and closing windows) to maintain indoor comfort levels.

– Not continuous ventilation, but only when the CO2 limit value is exceeded (1200), so in peaks.

– CO2 is higher against ceiling and floor, but lower at working height: that counts as a measured value. Hence the ceilings are also slightly higher.

Lecture by Junghans at ETH Zurich, the engineer behind the concept: (from minute 17 technical details)


* for embodied energy, it must be borne in mind that all figures are based on primary energy figures, which means that the actual final energy demand is re-calculated back to fossil energy use, usually with the national energy mix. This is of course strange if we want to compare actual use of energy in production. Moreover, they are often general or sector averages:: if the production uses  renewable energy, that is not reflected. In fact, production (embodied) energy figures should be given in enduse, with a free choice of a specific energy mix to add, avoiding  to unnecessarily multiply them with an inefficiency factor. Moreover, if we know that we have to switch entirely to renewable energy, it makes no sense if we now optimize to an energy source that has had its time. Anyway that’s a discussion I have in other areas …. [8]

[1] several websites describe the building::

and a follow up project::

[2] Environmental impact evaluation of energy saving and energy generation: Case study for two Dutch dwelling types, Michiel Ritzen, T.Haagen, Ronald Rovers, Chris Geurts

in: Building and Environment 108 ·July 2016, DOI: 10.1016/j.buildenv.2016.07.020


[4] IEA EBC Annex 57 Embodied Energy: All reports can be found here:  The described building is in the report of Subtask 4 pag 324 case studies.

[5] IEA EBC Annex 72 , publications to follow:.

[6] Broken cycles, This Summer in English available. Durch vesrion: Gebroken Kringlopen, Naar een volhoudbaar gebruik van bronnen, Boek uitgeverij Eburon, isbn 9789463012034 ,

[7] climateneutral:

[8] Primary energy:

[9] 2226 office, first one

2226 house in Graf

and in Simmental

and in Emmenbrucke

publikatie evaluatie:

Author: ronald rovers