Building a sustainable house does not have to cost a fortune. This article sets out how it works, and what changes when you build in southern Spain rather than in northern Europe.
Before the twentieth century, most houses were sustainable out of necessity. People lived in the countryside, energy was scarce and in many places there was no electricity supply at all. That shortage forced them to work with what nature gave them: if the main facade faced south, the sun warmed the rooms for free, and there was less firewood to cut and carry.
Then came industry, the towns grew and those habits were quietly forgotten. There is no good reason not to pick them up again in the twenty-first century, with the materials and the technology we have now. Below are the fundamentals of a self-sufficient house — and the points where this advice works differently on the Costa del Sol.
What is a sustainable house?
A house earns the name when it meets, broadly, the following:
- It protects the health and ecology of the site it sits on.
- It has a low energy demand, with renewables covering what is left.
- It uses natural, breathable materials.
- Its materials and its waste can genuinely be recycled.
- It manages water sensibly — on this coast, that means rainwater and greywater, not just low-flow taps.
- It pollutes as little as possible, in construction and in use.
- Its insulation is made from natural materials.
The key decisions when building a sustainable house
This is the order we work through them at our architecture practice in Málaga.
Orientation
Orientation is the cheapest energy measure there is. It costs nothing at design stage and you cannot change it afterwards. It matters while you are still choosing the plot, too: a site that sits in shade all winter is a problem you pay for every year.
Work out the solar angles before you decide where the rooms go. That tells you which spaces get the most light through the day, which ones warm up on their own, and how much heating and cooling you will end up buying. There is more on this in our guide to working out the orientation of a property.
One caveat for readers arriving from the UK or Ireland. Here the enemy is the summer, not the winter. A wall of south-facing glass that would be a gift in Yorkshire will cook a house in Torremolinos in August. The answer is the one the old houses already used: overhangs, deep window reveals, shutters, cross ventilation and thermal mass, sized for a sun that is high in July and low in January.
Renewable energy
Go for clean, renewable sources: solar, wind, geothermal, biofuel generators. Each buys you a degree of self-sufficiency and each suits a different job. On this coast solar does most of the heavy lifting, for the obvious reason — photovoltaic panels for electricity, thermal panels for hot water. Low-consumption appliances are part of the same calculation.
Worth knowing if you are new to the Spanish system: when you come to sell or let the house you will need an energy performance certificate (certificado energético), Spain’s equivalent of the EPC and a legal requirement rather than a formality. It is signed off by a qualified technician, and under Royal Decree 390/2021 it is valid for ten years — five if the property comes out with a G rating.
Building materials
Time to put the house up. Which materials should you choose?
Timber is the usual starting point, and one of the most ecological natural materials available, provided it comes from sustainably managed forestry. It can do the structure, the walls or the finishes.
Other materials worth considering:
- Adobe: bricks made from clay-rich sand and straw.
- Hemp.
- Straw bale.
- Recycled materials, such as glass bottles or plastic bottles filled with sand.
A word of honesty here, because this is where most articles stop. Not all of these travel equally well through the Spanish system. Timber and adobe have a long track record, and a building control officer will know what to do with them. Straw bale and bottle walls are another matter: expect questions from the structural and fire sections of the building regulations (the Código Técnico de la Edificación, Spain’s equivalent of the Building Regulations — DB-SE for structure, DB-SI for fire), and expect your mortgage valuer and your insurer to ask the same questions. It can be done. It simply has to be designed so that it can be defended on paper, not only on site.
How it looks
The style of a self-sufficient house deserves the same attention. Its lines and materials should sit with the setting rather than argue with it. That is why many of these houses borrow the forms of nature, and why their interiors tend to repeat the same textures and light.
There is a practical reason as well as an aesthetic one. Across much of Andalusia, local planning rules set out which roof forms, colours and volumes are acceptable in each area. A design that respects its setting is a design that gets its planning permission (licencia de obras) without an argument. That is time and money you keep.
That is the short version of how to put up a self-sufficient house. If you are weighing up a plot on the Costa del Sol, the useful moment to find out what can realistically be built on it is before you sign, not after. In the meantime, there is more on construction and sustainability on our architecture blog.
