The current GEG law is heating up the tempers. Fundamental discussions about heat pumps and gas boilers are dominating the public debate right now. But regardless of which direction you look in, energy costs will rise in the coming years. For this reason, the best energy is not consumed in the first place. The industry, on the other hand, is still trying to cram buildings full of 20th century technology and blow as much air as possible through shafts and ducts with huge amounts of energy. That's "old school." And has contributed decisively to the climate catastrophe.
But through better analysis and calculation methods, we can achieve a significant reduction in mechanical technology in buildings. We call this principle Stupid Home and Smartphone. To this day, the real estate industry still thinks the smartphone is for making phone calls. Unfortunately, it has not yet discovered the potential of this device for itself...

Consistent goals and team spirit

Low-tech buildings are designed from the ground up to achieve the required indoor environment with as little technology as possible.Successful low-tech buildings require consistent strategic goals.These must be clearly established at the beginning of the design process and reviewed with measurable metrics after completion, so that we can learn from the results and do even better next time.Classic sustainability criteria or requirements, as with DGNB or ESG, do not necessarily lead to low-energy buildings.Even the goal of enabling a so-called zero- or even plus-energy building is not self-evidently achieved by these sustainability criteria.
Holistic requirements, in combination with results-oriented planning and construction, on the other hand, result from a consistent life-cycle approach. In order to be successful here, the energy requirement should have a CO2 footprint better than zero during the period of use.This can only be achieved through plus-energy buildings.However, to ensure that the "backpack" from building construction for energy supply does not become too large, the selection of building materials already plays a major role.

Building envelope as a success factor

It is a good thing that building materials such as wood and clay not only reduce CO2 consumption in the construction of buildings, but also have a positive impact on comfort and energy requirements. Natural building materials and a solid building envelope enable efficient use of available energy. This does not mean the excessive use of technology, but rather the restriction to existing resources and proven techniques. A suitably solid façade can have a cooling effect in summer and store man-made heat in winter. Openable windows that ensure adequate air exchange are another crucial criterion. Nighttime ventilation is also a well-known and efficient method of thermally stabilizing buildings in summer. However, these concepts need to be transferred to our time to provide additional benefits and comfort. The keywords here are digitalization, artificial intelligence and related technologies. With our smartphones, for example, we can monitor oxygen levels and temperature fluctuations, create intelligent ventilation plans or simply be reminded to ventilate regularly.

A decisive role is played by facades, which not only regulate the incidence of light but also generate and store useful energy. Today, it must be questioned again and again whether the use of high technologies actually makes sense.

Do the resources saved outweigh the effort and consumption? Does the longevity of the building go hand in hand with the life cycle of the technology?

Gray energy and emissions must be calculated especially in connection with the building envelope, as it is of crucial importance for climate-neutral new buildings and sustainable revitalizations.

Building technology as a minimum principle

Once the foundation for a low-energy building has been laid by a good building envelope, the technical building equipment must be designed to avoid as much building technology as possible.

Heating and cooling must be reduced to the bare minimum. If this has not already been done through the choice of materials, systems with radiation components should be considered for heating. For (residual) cooling, adiabatic cooling systems enable optimized energy use. In addition to technical solutions in ventilation systems or by spraying water, technology can ideally be replaced by sensible plant troughs or "fountains". Air changes are to be solved, where possible, by natural ventilation. And in the case of lighting, a sensible design of window areas for daylight use should be aimed for, while a thoughtful room layout can achieve reduced technology for transport energy.

Storage instead of power

A lot of technology and "oversized plants" often have their cause in generous determination of corresponding consumption, usually in combination with a "fear factor", which is added on top. Appropriate plant sizes can be achieved with a qualified determination of heating, cooling and electricity requirements. Good practical experience and the evaluation of real buildings are certainly helpful here. In the vast majority of cases, the room occupancy is lower than assumed.

In addition, the normative performance calculation results from "extreme situations". Here, in coordination with the building owner, it can be examined to what extent these very improbable scenarios are necessarily taken into account in the calculation of demand.

In addition, the normative performance calculation results from "extreme situations". Here, in coordination with the building owner, it can be checked to what extent these very improbable scenarios must be taken into account in the calculation of demand.

The installed technology can also be significantly reduced with storage systems. Moreover, storage units have the advantage that they avoid the "cycling" of systems and thus enable more efficient operation. And this also has the positive side effect of reduced maintenance costs. Large "stratified heat storage tanks" are already very common. In addition to optimized operation of solar thermal and CHP systems, they are also essential for the increasing number of heat pumps. In combination with power-to-heat (P2H) units, the installed capacity of heat generators, and thus the use of technology, can be significantly reduced. And the use of suitable ice storage systems can reduce the cooling capacity of office and residential buildings by up to 50%.

Electricity storage systems not only optimize the degree of electrical self-sufficiency through possible PV modules, they can also contribute to a secure power supply. The need for emergency diesel generators can thus be critically questioned or at least significantly reduced. In this context, it is also worth pointing out a sustainable alternative.

"Stinky and noisy engines" may be replaced in the future by fuel cells capable of providing emergency power

a much cleaner technology with a smaller footprint. If, despite the possibility of reduced aggregates for generating the respective forms of energy, the aforementioned storage systems are still too "technical," another low-tech approach is the use of thermoactive ceilings or concrete core activation. This somewhat more inert system and the resulting storage masses can also reduce the output of heat and cold generation.

The power of the sun

All "residual energy" can theoretically be easily made possible with the use of solar energy. The use of fossil fuels can thus be easily avoided - all the more so in low-tech buildings. Solar thermal energy for heating purposes or PV modules for electricity generation are of course the most common solutions in building technology here. Optimized comfort can also be achieved through the indirect use of solar energy and the above-mentioned appropriate choice of materials. Wind turbines will only play a role in buildings in exceptional cases. Green electricity from such plants is then more likely to enter the building via the power connection, e.g. as a PPA

(Power Purchase Agreement).

Human factor 

People as users must also make their contribution to the efficient use of energy. After all, we produce heat 24 hours a day. So why not ensure that this energy is distributed and retained in the best possible way within the building? There is also a fundamental idea here: we need to develop a new self-image if we want to make progress sustainable. On the one hand, this concerns the incentive culture in the construction industry, which focuses too much on quantities and monetization instead of developing economical and efficient solutions or even social qualities. On the other hand, it is about what demands we should actually make for ourselves: Do we always just want to supposedly optimize everything, or do we want to create an environment in which we feel comfortable and which is nevertheless good for us, our environment and future generations? At the same time, one does not exclude the other. Especially since the human body is capable of dealing with a wide variety of environmental factors. For example, a room does not have to have the same temperature 365 days a year for us to feel comfortable in it. There may be fluctuations, but at the same time we can expect to regulate extreme temperatures in buildings, for example, or not to allow them to occur at all, in order to keep work and life at a comfortable level. The appeal is: Let's find user-defined solutions!

Users in particular should be more involved in the thermal regulation of their rooms. This is not about generating maximum, constant, thoughtless comfort. Rather, it is about a self-initiated thoughtful optimization of the parameters required for one's own comfort. If you can book your own trip on your smartphone, you can also use it to control your own room temperature. Why does a building still need a security camera and a doorbell? This could also be controlled via a QR code at the entrance and the smartphones of the users. Couldn't batteries also be charged while cycling and then used in the home instead of charging batteries in the home to make cycling to the gym easier?

Courageous builders required

But this also needs decision-makers in the real estate industry who break away from established conventions. They need to think about what is important for today, tomorrow, and the day after tomorrow, and they need to break new ground. At present, the real estate industry is dominated by false incentives and fears.

These include, for example, the use of excessive air-conditioning technology, excessive building standards and regulation. To overcome this, identity-creating and innovative building designs are needed. To explore new ways to develop the building industry system and inspire much needed transformation. This includes reducing the use of costly and high-maintenance technology and implementing new control methods instead.