First of all, what is an nZEB building? Marius told us that "to be part of the nZEB standard or passive house, a construction must be build according to the energy efficiency principles. First of all, thermal insulation must be continuous - meaning that we shouldn't just insulate the walls, but also the foundation, the roof and other structural elements."

At the same time, he says, it's important that a building does not have thermal gaps, where the heat or cold air leaves the building. An important component in this regard is mounting high-quality windows and doors, which must be properly installed by the experts in the industry, in order to avoid any possible thermal losses.

And to ensure fresh air inside, he recommends installing a ventilation system with heat recovery.

Old buildings brought to the present

The benefits of nZEB buildings are that a building can be renovated so that its carbon footprint is reduced, but this doesn't guarantee its optimal efficiency performance. Thus, in some cases, building a new construction would be the better option on the long run, even if the initial footprint associated with building it is higher.

"However, in order to determine this, you need to get an energy expert involved to have the building evaluated (who can check the building for any potential issues) and then they will make the renovating project. If the foundation wasn't insulated thermally, you can't do this at a later date and automatically, the building can't quality for the nZEB standard, although its performance will be improved", says Marius Șoflete.

And if the restauration of an old building is feasible to transform it from the energy efficiency stand-point, the owners must choose only high-quality materials, compatible equipment, as well as not overlooking the quality of the work to avoid, among other things, sealing issues.

The differences between a traditional building and a nZEB one are not that great, at first. Marius told us that the thickness of the walls is usually one of the first things that tells us we are looking at an nZEB construction, since it has thicker walls when compared to a traditional house.

Still, the benefits and more subtle differences come once you live or work in that kind of a building in the long run.

"First of all, a passive home has a better level of comfort. It is sealed, it doesn't lose heat and it doesn't need that many energy resources to produce it. The thing regarding energy requirements is essential, which means lower energy bills and independence from the energy bills fluctuations and this is due to the overall thermal energy efficiency, as well as the HVAC system or solar panels", says the co-organizer of the nZEB Expo.

Currently there are 28 nZEB buildings in the world and there are several other tens waiting for certification, according to experts at the Passive House Institute.

Maris explained that these buildings don't have any disadvantages, outside of maybe the higher-than-normal initial price. On the long run, this gets compensated through "the resistance and the energy efficiency. Also, such a building will protect you from the price energy fluctuations and if you want to sell it at some point, its value will be higher."

How to build an nZEB house in Romania

Marius told us that the passive house industry evolved significantly over the past five years. There are specialized project engineers that have been certified by the PHI and there are also several facilities specialized in the production of prefabricated wooden houses, offering owners integrated solutions. Also, there are materials and equipment suppliers that specifically work with these constructions, such as heat pumps or ventilation systems.

"More importantly, however, is that there are people specialized in checking the quality of these constructions. Many of these experts and their companies will be present at the nZEB Expo and will be speakers and will even organize demonstrations to offer the visitors the proper know-how they need", the engineer specialized in passive houses explained.

Unfortunately, Romania sits behind other European countries when it comes to the number of nZEB buildings, because owners in our country look closely to the initial construction price, overlooking the long-term benefits.

"Currently there are discussions about resuming the Green House program, which unfortunately is not enough for a building to become nZEB. A house doesn't become energy efficient just with solar panels, but it also needs proper insulation, to be sealed and so on", says the co-organizer of the nZEB Expo.

The nZEB Expo fair could facilitate the access to information for the industry members, as well as for those who want to build more efficient homes.

Carlos Moreno, the creator of the 15 minutes city concept will also be present as a speaker at the nZEB Expo fair, which will take place between the 14th and 16th of June in Bucharest at Romexpo.