• Daniel Butucel

HOW DO WE BUILD TO THE nZEB (nearly ZERO ENERGY BUILDING) STANDARD

Only nearly zero energy buildings will receive a building permit after 31st December 2020



What does nZEB mean?

According to Law no. 372/2005 and republished in 2020 regarding building’s energy performance, ‘’the nearly zero energy building is a building that has a very high energy performance, for which the energy requirement is nearly zero or it is very low and it is mainly covered by energy from renewable sources, including locally or nearby produced energy from renewable sources.”

The same law 372/2005 also mentions that “in order to supply the total power consumption of a nearly zero energy building, renewable energy sources (non-fossil), cover at least 10%of the total primary energy of the building”.


Why nZEB?

The European Union takes climate change and its impact on the environment very seriously, committing, in the long term , to becoming neutral regarding CO2 emissions from each sector ( civil engineering, industry, transport, agriculture), in order to create a thriving stable environment for the future generations. To this end, a series of long term goals have been issued for 2020, 2030 and 2050.


The buildings sector has a significant impact on the environment (40% power consumption and 36% CO2 emissions) and it has been one of European Union’s priorities for some time, EU which has issued directives and has set ambitious goals for future years. Among these goals, we mention Directive 2010/31/EU (EPBD) on thermal building performance that mentions the nZEB standard. Romania, as part of the EU has to align with this directive and to improve the thermal performance of the newly built and existing ?


We have written more on the environmental impact in this article.




The nZEB benefits

It goes without saying that the nZEB standard brings a benefit to the environment, thus contributing to the reduction of the building power consumption and by default their greenhouse gas emissions during their life-span. In Romania, the built-up fund amounts to 493.000.000 m2 in rural and urban areas and energy consumption ranges from 150 to 400 kWh/m2/year. When we report such values, every kWh/m2 saved is a considerable amount.


Most of the costs of a building during its life-span ( estimated at 50 years) are attributed to its maintenance ( over 70%), especially heating, as also indicated by the European statistics.


By reducing the power consumption, monthly maintenance costs are also reduced. Moreover, buildings’ owners rely less on the energy price developments, whether gas or electricity.



How do we implement the nZEB?

The nearly zero-energy buildings growth plan published in 2014 presents the NZEB standard extensively through energy efficiency measures, coefficients and economic and feasibility analyses based on the current situation of the built-up fund and the way in which it is built.

Energy efficiency measures include measures aiming to raise energy performance of the building envelope, also mentioned in the passive house standard: proper thermal insulation, energy efficient windows, reduction of uncontrolled air infiltration and reduction of thermal bridges. We have extensively discussed the passive house standard in this article. More than that, measures such as LED lighting, energy efficient heating/cooling equipment ( e.g. heat pump) or more efficient appliances are added. These accumulated to a primary energy requirement of up to 100kWh/square meter/year.

Furthermore, systems that cover the minimum 10% renewable sources requirement need to be implemented, including photovoltaic systems, solar thermal systems, wind turbines or heat pumps.

Naturally, all these energy efficiency measures entail additional investing costs. In the table II.11 extracted from the previously mentioned plan, an economic simulation of the investment in a single-family nearly zero energy household compared with a conventional one. Taking into account the cost of the energy and the greenhouse gas emissions ( additional taxes for pollution) over a period of 30 years, the initial investment in the nZEB standard energy efficiency measures (280 EUR/square meter) is not only amortised , but it will also create economic benefits after the calculation period (in 30 years the overall cost of an NZEB building is almost 2 times lower than the conventional one, 648 EUR/square meter as compared to 1207 EUR/square meter). Taking into account the investment cost as well, a nZEB house proves to be more economic in the long run.



Conclusion

All residential projects whose building permit was issued after 31stDecember 2020 will have to meet this standard. Things are changing whether we like it or not, and we can be certain of one thing: WE ARE GOING TO BUILD BETTER AND MORE EFFICIENTLY from all points of view. The benefits of nearly zero energy buildings are undeniable and the nZEB standard will stimulate the continuous professional training of those who design and build, will improve the development of certain sectors in civil engineering, will increase the level of comfort, will reduce the power consumption in this sector, therefore on the environment.


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