Brought to you by
Brought to you by
The possibilities for the application of Passive House components in the modernisation of existing building stock was systematically investigated in the 24th session of the Research Group for Cost-effective Passive Houses [AKKP-24] , and the special aspects of building facades that are worth preserving were dealt with in the 32rd session of the Research Group [AKKP-32] . The challenges of carrying out individual renovation measures and ways to achieving an optimal final state, were addressed in Research Group No. 39 “Step-by-step modernisation using Passive House Components”.
After the successful realisation of a whole series of pilot projects, the modernisation of existing buildings using Passive House components is finally ready for implementation on a large scale. Since then, enough time has passed to assess whether the finished modernisation projects have proved successful in operation. After completion of the Tevesstraße (Frankfurt, Germany) and Hoheloogstraße (Ludwigshafen, Germany) projects, comprehensive metrological examinations were carried out by the Passive House Institute, the results of which are shown in the following illustration:
|Calculated (PHPP) heating demand of existing
building stock and calculated heating demand
and measured consumption (adjusted for an
interior temperature of 20 °C and standard
climate) after modernisation of the projects in
Tevesstraße, Frankfurt a.M. (ABG Frankfurt
Holding, architecture by: faktor 10 GmbH) and
in Hoheloogstraße, Ludwigshafen (GAG
Ludwigshafen) (see [Peper,Feist 2009]
and [Peper,Grove-Smith,Feist 2009] ).
At each step of the refurbishment the question that should be asked is: which alternative is more “worthwhile“? The result of these analyses of the respective burden over the period of use shows:
|If insulation is to be applied, it should be done properly.
This basic principle applies to older buildings and new
constructions alike. If it is properly carried out, the facade
will not need to be renovated again for a long time.
Retrofitting with Passive House level insulation is econo-
mically ideal under the present and future conditions.
Less insulation is bad for the budget now – and even
worse in the future.
Thus, the principle to be followed, as we have always maintained, is: if it has to be done, it should be properly done! To stop at moderate insulation would be a waste of money. It should also be considered that it would be practically impossible to carry out “subsequent improvement“ with justifiable effort: while it is possible to carry out the better measures today at low differential costs, later installation would require the same effort once again for scaffolding, installing, protection from weather etc. (this would not be profitable under any circumstances). That is why, from the very beginning, great attention must be paid to a high quality of the thermal and energy-relevant aspects of each procedure. When it is time for the relevant building component to be renewed anyway, then scaffolding will be put up and all remaining measures will be carried out in any case, thus the additional effort for a qualitatively better implementation will be very small.
There are some other reasons why better measures should be preferred:
The excellent thermal protection of the same level as the Passive House components is not only economical but also preferable in all aspects.
The economic situation is even better for the owner: the interest subsidy programme of the German government through the KfW’s “Energy-efficient Modernisation” programme provides an equivalent of 15 to 25% of the total investment for the measures. Many countries and regions in Europe have similar programmes, as in most Austrian States for example.
The return on an investment in one’s own house (for energy-saving purposes!) is then almost 10%/year – an absolutely secure investment, although there is the risk that energy prices will increase even more in the future (the measures are even more worthwhile in that case). Not only are the profits safe but they are also tax-free as they are the result of saved heating costs. The most attractive measure economically is clearly the improved thermal insulation of the same quality as the Passive House; and the building owner and residents also benefit from all the other advantages, which have already been explained.
The following demands are made on home ventilation, mainly for reasons of hygienic air:
It goes without saying that the systems used should be quiet, ventilation should not cause draughts and the air should be warm and have a good hygienic quality. Here too, Passive House systems are preferable in all aspects.
The following illustration shows the differences in savings for an actual property when only mediocre components are used (low-energy refubishment) and when a refurbishment is carried out using Passive House components. Only the latter case provides a sustainable option.
|Annual heating demand for an unrefurbished old
building, a “low-energy” refurbishment, and a
refurbishment using Passive House components.
The comparison shows how important it is to achieve the highest possible level of energy efficiency that is economically viable. Only then will it be possible to reduce energy consumption to a level which is both affordable and ecologically sustainable. A variety of independent studies carried out on realised buildings have proven that the methods presented here are successful in all respects. Today, we know that
[AkkP 24] Einsatz von Passivhaustechnologien bei der Altbau-Modernisierung; Protokollband Nr. 24 des Arbeitskreises kostengünstige Passivhäuser Phase III; Passivhaus Institut, Darmstadt 2003.
[AkkP 32] Faktor 4 auch bei sensiblen Altbauten: Passivhauskomponenten + Innendämmung; Protokollband Nr. 32 des Arbeitskreises kostengünstige Passivhäuser Phase III; Passivhaus Institut; Darmstadt 2005.
[Kah et al. 2008] Kah, O.; Feist, W.; Pfluger, R.; Schnieders, J.; Kaufmann, B.; Schulz T.; Bastian, Z.; Endbericht: Bewertung energetischer Anforderungen im Lichte steigender Energiepreise für die EnEV und die KfW-Förderung, Passivhaus Institut, Darmstadt, 2008 : To download it free
[Peper, Feist 2009] Peper Dipl.-Ing. Søren; Feist, Prof. Dr. Wolfgang: Gebäudesanierung „Passivhaus im Bestand“ in Ludwigshafen / Mundenheim, Messung und Beurteilung der energetischen Sanierungserfolge, Hg. von Passivhaus Institut Dr. Wolfgang Feist, Darmstadt, 2009.
(Refurbishment of buildings – “Existing Passive House” in Ludwigshafen/Mundenheim, Measurement and Evaluation of the successful energy-efficient refurbishment, published by Dr. Wolfgang Feist, Passive House Institute, Darmstadt 2009)
[Peper/Grove-Smith/Feist 2009] Peper, S.; Grove-Smith, J.; Feist, W.; Sanierung mit Passivhauskomponenten, Messtechnische Untersuchung und Auswertung Tevesstraße Frankfurt a.M., Darmstadt, 2009 : To download it free
[PHPP 2007] Feist, W.; Pfluger, R.; Kaufmann, B.; Schnieders, J.; Kah, O.: Passivhaus Projektierungs Paket 2007 (Passive House Planning Package 2007), Passive House Institute, Darmstadt, 2007 (Link to description: PHPP-Contents (Passive House Institute)).
[Vallentin 2008] Vallentin, Rainer: Herleitung belastbarer Klimaschutzstandards im Wohnungsbau, 12. Internationale Passivhaus Tagung, Nürnberg, 2008