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Energy-Efficient Modernisation

Building renovation – a topic addressed by politics and society in equal measure. A large proportion of the office and residential buildings in Germany still do not meet modern energy efficiency requirements. But clients and users want to keep the loss of utility and rent caused by renovations as low as possible. This calls for systems that feature a high level of prefabrication and can be easily installed in the existing fabric of the building.

Joachim H. Faust - Managing Director of HPP GmbH + Co. KG

Energy-efficient modernisation is an architect's responsibility

The current public discussion regarding the thickness of insulating material on external façades is too one-sided. Today’s client will not be persuaded to invest more money in the façade of a building if lower operating costs are the »only« prospect.

Energy-efficient modernisation will be successful if, in the long term, the functionality and design of´ the modernisation is of a high quality. To achieve this, an awareness for innovation, rather than dated recipes for renovation, must predominate in the minds of everyone involved. Over the past few years, our office has designed many renovation projects, and has even converted listed buildings to meet the energy efficiency requirements of the modern age. As architects, we are always on the lookout for solutions that provide a suitable answer to the specific location and task. The industry helps us in this respect by supplying innovative products. The building envelope, roof and façade are the priorities for energy-efficient modernisation. Windows with U values of 0.8–1.4 W/m²K, highly efficient insulated profiles with narrow face widths and integrated fittings, triple glazing with a high level of daylight penetration, external and wind-resistant solar shading, thermal insulation in the glazing rebate, etc. are important innovations. The industry has developed system solutions and products for façades in particular which offer comprehensive, meaningful solutions in terms of technology, energy savings and architectural design. Thermal insulation on its own, therefore, is not the decisive factor, but rather solutions which minister to the appearance and function of a building, thus satisfying the requirements of the clients and users. Ready-made solutions are of little help here; it is the optimised interplay of innovative solutions which achieves the desired results.

Joachim H. Faust

Alexander Widlowski - Architekt h4a Gessert & Randecker Architekten BDA, Stuttgart /GER

Modernising means improving quality

It is not a question of saving money, but rather building economically. Every decision always has a counterpart. The holistic optimisation of projects is therefore the most effective way.

PROFILE: Where is the greatest potential for savings when modernising?
Alexander Widlowski: For an energy-efficient modernisation, the most simple measure is clearly to renovate the façade, which makes up the majority of the envelope. Cost effective is when a building can still be fully used after 25 years. The solution which is presumed
to be the most economical may bring follow-up costs in ten years. It is always important to ensure a reasonable quality level, because the fact is that construction costs only equate to approximately 20% of the costs that need to be provided for over a lifecycle of 30 years. The surface finishes and appearance are often firmly decided. The underlying technical points and thelifecycle aspects can often only be explained with difficulty. At the same time, that is precisely what is relevant in the long term.
PROFILE: The ERC 50 modernisation façade allows a façade to be renovated from outside, whilst the building is still in use. Do you see advantages in this?
Alexander Widlowski: Yes, if we are talking purely about renovating the façades of private properties, certainly. Of course, the new envelope has to suit the property in terms of design. If so, I would suggest a system like this. That could make a lot of things easier – provided it leaves enough design freedom. In principle, that is a great thing.

Gonzalo Alava - Bauwerke Architekten, Berlin/GER

Cost is a decisive factor

PROFILE: Is energy-efficient modernisation an issue for you?
Gonzalo Alava: Yes, our office normally works on conversion and renovation projects.
PROFILE: Where do you see the greatest potential for savings
there? And what role does the façade play?
Gonzalo Alava: The main role, of course! Then the connections between window and façade. The profiles are very important. Today everything is extremely well sealed but, for passive house requirements, the sealing has to be even better, so that it works.
PROFILE: Do you renovate buildings whilst they're still in use? If so, what criteria must be right for it to be possible?
Gonzalo Alava: Yes, we do. There is, of course, always the question of costs. The condition of the building is also critical. It might not be worth it if the cost of investment is too high. Or, for example, if it's a listed building, then it's out of the question.