Bioclimatic construction in Idealista News
On October 17, Idealista News published an article on Bioclimatic construction: how to achieve an ‘eco-friendly’ home with nearly zero consumption, featuring our firm as an expert in sustainable, ecological, and healthy architecture.
In the article, we answer a series of questions regarding strategies to ensure bioclimatism, energy efficiency, and the sustainability of the spaces we inhabit:
Is it more expensive to build an ‘eco-friendly’ house than a standard one?
If we speak exclusively about energy consumption—which for us is already a matter of the past century—there is no additional cost as such. This is because we achieve reduced consumption primarily through bioclimatic design, lowering energy demand via passive means such as solar gain and protection, thermal mass in construction materials, and high levels of insulation and airtightness.
Currently, the prevailing Technical Building Code has mandated that homes be zero or nearly zero-energy since 2020. Therefore, discussing extra costs in this field no longer makes much sense, as it has been a mandatory requirement set by regulations for several years now.
It is a different matter if we discuss sustainability in terms of the consumption of limited planetary resources and the environmental and health impact on people, which would be the correct definition of sustainability in construction.
Regarding planetary resource consumption and environmental impact, if we compare the same house built with low-impact materials to a so-called “conventional” home built with materials with a high ecological footprint—such as concrete, steel, and plastics—and focus solely on the cost per square meter, the additional cost can be in the range of 30% to 50%.
However, sustainable architecture is not an option to be compared; it is a necessity and an urgency due to the climate emergency we face. Therefore, it is not about comparing, but about striving to carry out zero-impact projects in an economically viable way. This is not just a matter of sustainability; it affects the health and well-being of users, as well as the planet we inhabit.
To realize a sustainable home, we cannot expect to finish the project and then go to tender with natural and low-impact materials, because the numbers will never add up. It is necessary to establish a strategy from the beginning of the project, starting with the sufficiency of square footage, moving through the valuation of materials, and reducing unnecessary finishes and installations.
Carrying out a sustainable project in terms of zero impact is economically viable when an integrated strategy is proposed from the very start of the project.
What consumes the most energy in a home?
In homes that are more than 10 or 20 years old, predating the most recent energy efficiency directives, the most significant expense is, of course, heating in winter and air conditioning in summer. These are houses with very little insulation and poor airtightness, where heat exchange with the outside is guaranteed and hygrothermal control is non-existent.
In recently built homes—following the 2020 update of the Technical Building Code which already requires zero consumption—if they have been executed rigorously according to regulations and both insulation and airtightness are adequate, and passive control strategies typical of bioclimatic architecture have been implemented, heating and cooling consumption is reduced. The bulk of electricity expenditure then becomes the generation of domestic hot water, which can easily be produced using renewable energy.
Are there subsidies or tax incentives for sustainable renovation and construction?
The most relevant subsidies currently available are focused on renovation, as the European Union has made a very significant commitment to the rehabilitation and updating of buildings to reduce the energy consumption of all those structures with poor insulation or low airtightness.
In many cases, there are also grants at the municipal level, especially focused on property tax (IBI) rebates, which allow for the rapid amortization of renewable energy production installations.
For new builds, there are currently almost no subsidies. However, the investment in a zero-consumption, low-impact home is quickly amortized, as it is possible to build a house that not only consumes no energy but may even produce more than it uses. This is not to mention the benefits to well-being, comfort, and health provided by a home built with natural and respectful materials.
What sustainable technologies or systems do you typically implement in your projects?
We are in favor of reducing technology, as bioclimatic design allows us to achieve consumption reductions of around 80-90%. Most of the homes we build today no longer require heating and cooling systems to achieve average comfort temperatures of 18 to 24 degrees Celsius throughout the year.
Thus, the first premise would be to reduce consumption and, from there, cover the remaining demand with renewable energies such as solar panels.
In fact, the problem with technology is usually that it has a limited lifespan with an average turnover of 7 to 10 years, compared to a house that has a useful life of 100 or 200 years (or even more depending on the construction systems used). This is why any investment we can allocate to bioclimatic design instead of installations and technology will be easily amortized.
How much can energy consumption be reduced with bioclimatic design?
Passive bioclimatic architecture can reduce energy consumption by up to 80-90%, and this extra demand can be met with renewable energies, such as solar panels, provided that the site conditions, location, and surroundings are favorable.
Can all houses be more ‘eco-friendly’?
Yes, of course. We work with century-old homes, some over 100 or 200 years old. These are houses built with mortar and lime walls that possess exceptional thermal inertia, so with simple interventions in exterior insulation and airtightness, we achieve surprising results in terms of energy efficiency.
In most homes built 20 or 30 years ago, the construction base is good, but at that time insulation or airtightness were not taken into account; these are interventions that are quickly amortized through energy savings.
It is always necessary to keep in mind that when we carry out an energy renovation, we must work with natural and breathable materials and avoid plastic insulation that does not allow for the natural transpiration of the walls, which can lead to dampness and condensation.
How much can be saved by opting for a house with bioclimatic design?
If the house complies with current energy efficiency regulations, has a bioclimatic design that reduces energy demand, and energy production is achieved through renewable resources, the consumption costs of a home today are practically zero.
What changes must be made to further encourage ‘green’ construction?
For us, the essential change is that emissions start to be calculated in building regulations. Several countries in the European Union already include limitations on energy demand and the control of CO2 emissions and the impact of construction materials in their building codes.
This is going to be the new reality in our country, as the draft of the Energy Performance of Buildings Directive (EPBD) published last March—with final approval expected next year—no longer speaks only of energy efficiency, but of the calculation of CO2 emissions. This is the necessary and urgent change we must make.
This is where natural, sustainable, and low-impact materials will start to become competitive—when we consider the costs to the planet of opting for polluting materials that are contributing to the climate crisis we face.
What small habits or installations can people incorporate into their daily lives to make their homes more ‘eco-friendly’?
The main habit we always recommend is to inquire and research every material or modification we are going to make in our home. For example, if I have to change a floor, I can ask myself what the lowest-impact local production option is that includes non-toxic protection.
If I have to decide on parquet, I should understand how much wood it incorporates relative to chipboard with resins that may be toxic, and find out if the top layer is wood or a photo of wood covered in plastic that will electrostatically charge the environment.
In the case of changing window frames, we can inform ourselves about the impact of PVC compared to the impact of aluminum or wood, and the well-being or thermal comfort that one material or another will provide.
When we buy a sofa, we can investigate whether the textiles it is made of are sustainably produced or if they incorporate flame retardants or stain-resistant products that could be toxic and linger in the environment throughout the product’s useful life.
In summary, the most important habit we should have in our homes is to be conscious of every decision we make.