The first passive house on wheels in our country 99% of the time will not need heating

Raya Lecheva

A caravan, a mobile home on wheels or a zero-energy mobile home is already a fact in Bulgaria and is valued at BGN 40,000, but it is not for sale, said Dragomir Tsanev, executive director of the Center for Energy Efficiency "EnEfect".

The first passive house on wheels in our country was presented at the Architecture and Construction Week exhibition by "EnEfect" and is part of The NZEB Roadshow initiative, in which a total of five countries Bulgaria, Romania, Croatia, Greece and Italy participate.

This passive house on wheels or caravan is roadworthy and can be your home anywhere. It is 4.20 m high at its highest point, 2.50 m at its lowest point, 2.50 m wide and 4 m long. But what is more important? The mobile home meets the gold standard for zero-energy building and passive house. Its construction is made of metal and wood, in which there is 20 cm of insulation, triple glazing. On the inside, there is a membrane that provides ideal vapor barrier and air tightness. The passive house has a ventilation system with recovery, which is extremely compact and silent. When the building has a high air density, we must ensure a greater air exchange constantly. The air movement and purification provided by the ventilation system is healthy for us and should be present in all buildings, the experts commented. According to "EnEffect" studies, in Bulgarian bedrooms in the morning, carbon dioxide saturation is four times higher than the norm, which is dangerous for health. This was the result in all homes surveyed. "We can't get up at 3 a.m. to open our windows, it's better to have a smart system that takes care of that," commented Dragomir Tsanev.

Rather, we should think about how we will cool ourselves in the summer

One more important detail, this building really does not need heating. 99% of the time there will be no need for heating, the heat in it is completely sufficient to ensure a normal living temperature. The problem is more in the summer because all the warm inflows raise the temperature. That's why we have a highly efficient heat pump to help with cooling. In the summer, this heat pump is powered by a photovoltaic installation, which is about 3 kWp and will be completely sufficient for energy needs, said Alexander Stankov from EnEfect. Ordinary old air conditioners do not have such efficiency, and there are already solutions that give us four times more energy than a unit of electricity we use, Tsanev added.

All these elements are part of the zero-energy building standard and fulfill the passive house standard.

Interestingly, when you leave a passive building for a week, even if you go on vacation and come back and leave it at 20 degrees, the temperature will have dropped to 17-18 degrees. You will need very little energy to bring it back to 20-21 degrees. Whereas with standard construction it is not. You'll come back, but if your building isn't insulated, you'll find it at 11-13 degrees and it won't be pleasant and you'll have to crank all the appliances to the max. In the passive building, there are no drafts, no unpleasant cold when you approach the window, there is constant ventilation with fresh air. Today we think that these are things that are not important, but in the end they cost money, because the health effects of poor living conditions can be too expensive for us, said Tsanev.

Not only that, the mobile home on wheels with such a construction is earthquake resistant.

The passive house can approach the prices of a standard building

The mobile house was made to show that zero energy buildings are not science fiction, they are happening in Bulgaria at very affordable prices. With enough knowledge, it is not that much more expensive to make compared to conventional construction.

This mobile home is made with materials that are in mass production in Bulgaria at the moment. Our job was to optimize the energy parameters and improve the project so that it meets the highest energy performance. So there is someone to do it and I hope that with this realization people will see that this is possible, comments Dragomir Tsanev. Not so much to influence the caravan market as to make it into standard construction as well. Regardless of whether we are making a caravan or another building, the principles are the same.

Still, it's easier to make a standard building than a caravan. When there is good thermal insulation, three-layer window frames with a warm spacer, installed correctly, when we have air tightness, when we have ventilation system and of course a heat pump with renewable energy, then we are protected from rising energy prices, because even in the coldest winter we need a very small amount of energy.

The first passive building in Bulgaria that we built was Gabrovo in 2015, certified by the Passive House Institute in Germany, Tsanev recalled. The cost increase was 7.2% over the norms of the time, expected to pay back in 7.5 years at the energy prices of the time, and then we had a problem with many materials and components. However, for a kindergarten that is in use for at least 50 years, the initial investment is recouped in seven years, and from then on it is in constant profit. Also, energy prices were low then, now they are higher.

He also gave an example of the measurements made on the first 1000 buildings in Brussels after the passive house standard was announced and in 2014 the difference in price with standard construction was zero.

Energy efficiency should be a priority, not a luxury

The most important thing is that energy efficiency is in the first place for people, for designers, for contractors. When designing a building, it is important what will be prioritized. Whether we want it to be energy efficient or have marble on the stairs or have gold faucets. We can tell the designer to save on the faucets, make the balcony smaller, but add 5 cm more insulation.

When priority is given to energy efficiency, then the prices are equalized with the prices of standard construction, Dragomir Tsanev is emphatic.

It took us a long time, because there are not many personnel in Bulgaria who can install similar types of materials, and it was necessary for representatives of the companies that present the materials to personally come and install the materials in order to achieve the quality we want, Tsanev said. Therefore, together with the Bulgarian Chamber of Construction and the National High School of Vocational Education and Training, the Agency for Sustainable Energy Development, we are working on creating a road map for training on energy efficiency and renewable sources. It will be ready by the end of this year, when the rules will be ready for what workers in the construction sector need to know in order to implement such projects, Tsanev added.

As part of The NZEB Roadshow initiative, 7 events have already been held in Bulgaria with the aim of training on the topic of energy efficiency, and there will be a total of 30. Based on a successfully functioning network of partner training centers from 5 countries in South-Eastern Europe - Bulgaria, Romania, Croatia , Italy and Greece, are building active professional and user communities. The goal is for professionals, as well as people, to become familiar with better quality and more beautiful energy-efficient buildings, which not only save costs, but also improve comfort and healthy living conditions. The Bulgarian caravan has the highest air tightness indicators. The Croatian Caravan won the National Geographic Award for Best Educational Project. The Romanian zero-energy caravan attracts the interest of over 4,000 people in Cluj.

Where else can you see the zero energy caravan?

On April 22 and 23, the caravan will be part of an interactive educational event in Sofia Ring Mall. On the eve of Earth Day, the organizers want to introduce and inspire children, youth and their parents to achieve a greener future by using the basic principles of energy efficiency. At the end of May, a similar event will be held in Burgas. The models of the caravan will be presented June 20-22 in Brussels at the European Sustainable Energy Week, which is the biggest event of the European Commission. The main goal is also to work more and more closely with Bulgarian universities in order to expand the understanding of energy efficiency, comments Dragomir Tsanev. That answers the question of why it isn't selling. It is an educational project to introduce us to the advantages of zero-energy buildings. Maybe you don't know that our buildings emit 40% of harmful emissions, and the goal of Europe and each of us is to live healthier and longer, right? The caravan can travel and reach every corner of the country as long as there is interest.