Even though Polish-English language barrier, I can tell that the audience enjoyed Tomasz Mroz´s and Mario Bodem´s presentations on passive houses including a number of questions from the audience. Here are some thoughts from the Polish audience about the marketing approach of a passive house, investments and effectiveness of energy-efficient renovation, and technical solutions in buildings.
Participants in Swegon Air Academy seminar in Krakow were really not shy and asked many questions about energy-efficient buildings. The first of many questions was related to investments in existing and new buildings, i.e. what is the payback time in both cases and should we rather focus on new buildings? Mario´s response was that if the existing building is in good condition (as bricks and concrete structures) and the layout of the apartments are good, and then it is worth keeping. Building a new multi-residential building in Germany costs approximately 1,300-1,400 EUR/m2 compared with a renovated concrete apartment building equaling to 375 EUR/m2.
Mario stated that the impact value on the building after renovation is huge if the certain approach is kept: “We do not renovate for saving energy, we renovate when it is needed. If the building needs renovation anyway, you just calculate the difference between really good and average renovation, and that usually leads to the payback time of less than 10 years. In this case, you save money for energy but also in that particular city area they are having problems with renting apartments and now (after renovation) all of them are rented and the owner can even raise the rent.”
According to Mario, the more extreme efficient renovation would be 30% more expensive compared to the normal renovation, but this project got 20% subsidies from the government because it was energy-efficient renovation. Also the costs and payback time are documented, as all calculation were checked, the work execution was also checked that is was done as designed. Also the government institution receives actual consumption values for the next three years in order to see the actual efficiency of renovation and to pay out money from the grant. This also reflects on another question from the audience about how to calculate the effectiveness of renovation. Mario said that in industry all is so far based on calculated energy analysis, but a good approach is to keep in touch with owner to get the actual data for future analysis.
Some participants were interested in the existing versus new heating systems in Mario´s apartment building. In the renovated building, the radiators were kept but the heating source changed from oil to pellets. This allowed lowering the temperature in the system and keeping the traditional over-sized radiators. This question led to the question about humidity and dry air in passive houses, where ventilation system in a passive house is necessary to achieve good air quality and only the necessary amount of air is heated, otherwise when the air volume is increased and heated, then this result in a dryer air.
The seminar concluded with a heated discussion with Tomasz Mroz in Polish language about marketing approach of a passive house concept versus politics and economic aspect of a building of passive houses. It seems that it is the understanding of the concept of nZEB that the nearly zero-energy building will be based on the passive house technologies / techniques and additional renewable systems / energies. The Swegon Air Academy seminar concluded with monitoring of passive houses which should be placed in action in order to prove that the passive house standard (and any type of energy-certified building) can be achieved in reality and it is not just promises on paper and design.
Image by Petra Vladykova