Nearly Zero Energy Building, what challenges and opportunities exist in Spain?

The Nearly Zero Energy Building (nZEB), also known by its English acronym (nearly Zero Energy Building), is considered the great opportunity for the construction sector to become fully sustainable. It is also an opportunity for the auxiliary industry and presents a very interesting challenge for building designers. The nearly zero energy architecture is preparing to transition to the regulations that will come into force in less than two years.

Since 2018, there has been a requirement for all public construction to implement the nearly zero energy building, the biggest challenge in energy efficiency in the sector. Starting in 2020, all buildings constructed in our country will have to comply with the nZEB standards, which primarily ensure that homes or other spaces require virtually no energy and are completely sustainable.

While in some Nordic countries this type of construction has been a reality for some time, in Spain the intervention of the European Union has been necessary for the sector to start transforming towards this model. Who is making the greatest effort? The architects specialized in nearly zero energy buildings, many of whom have transitioned from other traditional sectors.

The puzzle that architects must solve in face of this new way of building is that they have to follow the guidelines of the EU Energy Efficiency Directive in Buildings. Basically, what is presented there is that the energy consumed by these homes must be generated from renewable sources. Some of these will be located on the property itself and others in the surrounding area.

On the other hand, architects must ensure that these alternative energy sources do not affect the health of future occupants. Orientation, insulation, ventilated facades and roofs, solar panels, thermal systems, and of course, mechanical double-flow ventilation solutions are key in this new way of building.

What professionals note about nearly zero energy architecture

Architects must focus on maintaining affordable costs, prioritizing the needs of nearly zero energy architecture. They agree that for this type of new building design, the most noteworthy would be:

1. The location and site of the building. Latitude offers solar angles that need to be avoided in summer and utilized in winter, as they will provide free heat. One architectural solution is to plant deciduous trees that shade the building in summer and whose leaves fall as temperatures drop. Another good solution is to place windbreaks outside the homes to protect against cold climates.
2. The construction orientation. We must find a way that provides the necessary comfort without resorting to traditional air conditioning methods. Professionals believe that it is a good solution to resort to vernacular architecture, which adapts to the regional needs of each community. It is also necessary for the building to be compact and have a better orientation toward the south. Another solution is to place cold rooms, such as bedrooms, on the part of the building that receives little solar radiation, to the north. Likewise, the sun can be harnessed to preheat rooms occupied during the early hours of the day. Architects also recommend installing horizontal louvres on the south side and vertical ones on the east and west sides.
3. Envelope solutions. Since buildings lose heat through walls, floors, and ceilings, a high level of insulation should be adopted, specialized carpentry, and thermal bridges should be avoided.
4. Energy efficiency. For this, it is essential to have mechanical ventilation systems, among which double-flow options stand out. Also options like geothermal systems, Canadian wells, aerothermal energy, wind energy, and of course solar panels.
5. Adaptation to each climate. With nearly zero energy architecture, the necessary adaptation to each climate is more important than ever. In warm and dry areas, overheating must be avoided while enhancing solar capture in winter. In contrast, if the weather is humid, ventilation will be even more necessary. Cold climates also change and require greater insulation, solar capture, and nighttime ventilation in summer.

There's no doubt that the future of nearly zero energy architecture is tied to this requirement from the European Union. While many builders still need to adapt to this new situation, architects are in a better position and for many of them, this is a new way to find challenges and ways to develop their work. As we have said, starting in 2020 all buildings in our country will have to be nearly zero energy buildings.