How do we face the Nearly Zero Energy Building?

The problems of pollution are already among the priorities of the governments of the European Union, and that is why from 2020 all constructions that are carried out in our country will have to be Nearly Zero Energy Buildings. What does this mean for the construction industry? A huge change, which leads builders to create homes and offices that practically do not consume electricity, gas, or other supplies. However, what energy challenges does this present in a country like Spain?

The Nearly Zero Energy Building has a series of implicit characteristics, such as the need to use a mechanical ventilation system to ensure proper airflow, or a building tightness that solves heat loss in winter and prevents rooms from becoming very hot in summer. Nearly Zero Energy Buildings must also incorporate renewable energy technology, hot water heating systems, and low-consumption appliances. All of this is collected in the Basic Document HS3 of the Technical Building Code.

However, according to the European Union, Spain -along with other Mediterranean countries- is considered one of the territories that are least advanced in implementing the Nearly Zero Energy Building. The energy challenges of Spain are greater, but that does not mean they are avoidable. So during the next year, it is understood that many behaviors in construction will need to change.

How does our country face this change in legislation?

Main energy challenges in Spain

On one hand, at the social level and from the administration, companies and even the citizenry still mostly do not know this new way of building. It has only now that regional and central governments have started providing information on this matter, and while in northern Europe it is common to talk about it, in Spain it is still not.

Likewise, the climate does not help in our country. Many of the certifying seals specialized in sustainable homes, such as Passivhaus, have been developed in the north of the continent, where the climate is much colder. In Spain, there are both warm areas and very hot areas. And that poses a whole challenge.

Another very important challenge is the large Spanish housing stock, which totals about 25 million properties. Two-thirds of these are more than 30 years old, representing an added problem in achieving more efficient cities -it should be noted that most pollution is produced by buildings through demand for supplies-, given that the European obligation for Nearly Zero Consumption is only for new constructions.

To achieve renovations focused on the same criteria included in the Basic Document HS3 and for old buildings to also be nearly zero consumption, the help of the administrations will be needed. Above all, because renovations of old buildings to adapt to Nearly Zero Consumption are much more expensive than the same work on new buildings.

We must also consider among the energy challenges for the construction of Nearly Zero Energy Buildings that the European regulation does not specify how each territory should adapt to the imposed requirements, but rather that each State must provide said justification based on its own particularities. And, for now, in Spain specific criteria on how to implement this new construction model have not yet been established. Fortunately, specialized architects in the sector are laying the foundations for how this regulation should be applied.

It should also be noted that regulatory changes will not remain forever in the current state of the Basic Document HS3. The Nearly Zero Energy Building establishes that sustainability criteria must be reviewed at set time periods, meaning there will need to be constant adaptation to new changes.

Lastly, among the energy challenges in Spain regarding the standardization of Nearly Zero Energy Buildings, it is important to remember that Spain is one of the European countries the least aware of the need to invest in sustainability. And this is something that must improve over the years; collaboration from the administrations is also necessary to put the need for clean air. on the table.

What advice can be given to builders who do not know how to face these technological challenges? Apply some of the sustainable certifications, as they are much more advanced and comply with European regulations. For example, BREEAM, which is in Spanish and is easy to apply.

In addition to certifications, there are also organizations that promote Nearly Zero Energy Buildings such as the EECN Congress. The main professional meeting forum where to address the current state of High-Efficiency Buildings and the implications they represent for the construction sector, the construction industry, architecture, and the related services in our country, of which we are part of the Technical Committee as experts in intelligent ventilation and energy efficiency.