How to do a sustainable renovation in Barcelona?

In this post ‘Sustainable renovation in Barcelona’, you’ll find the different options to renovate your apartment in warm-temperate climate with high humidity considering some Passive House standards.
In other words, you’ll get the 5 keys to transform your apartment into a Passive House (well, something close to that).

In case you don’t know us yet, let me introduce myself, I’m Esther Rovira, founder of ERA architects, architect in Barcelona and passive house designer for sustainable renovations, passive house new builds and self-sufficient off-grid houses in Barcelona area and Catalonia.
I hope this 5 tips help you!


The Passive House Institute specifies that a renovation of part of an existing building will never be a passive house.
This is because not in all cases we’ll be able to match the strict parameters of the German institute.
The Passive House also doesn’t allow to certify a part of a building.
This means that the sustainable renovation of your Barcelona apartment cannot be certified without considering the whole building.

I’ll tell you something, the Passive House standards are rules defined by German physicist for German weather.
So, in areas like Barcelona with other climate and humidity; BUT ALSO multi-property of buildings and less government subsidies for renovation, it may be more difficult to apply a certification.
EVEN SO, it’s undoubtedly the most prepared standard to face the future challenges of climate neutrality in 2050 and moderate energy consumption in homes.

The most efficient thing for a passive renovation is to insulate on the outside (over the façade).
But if you don’t want to enter into a global project with your neighbors, it’s best to insulate from the inside (faster, cheaper, fewer problems).
Depending on the sunlight and orientation in Barcelona, ​​you’ll usually need 6-10cm of insulation on the façade.
It does not hurt to insulate floor and ceiling with 5cm (unless you are on the top flor, then you’ll probably need waaaaay more than that).
In order to choose the most efficient thickness of insulation and material, it’s best to have a Passive House Designer Architect calculate it for you by doing a Passive simulation.

For a sustainable renovation in Barcelona, you must change all the windows.
The reason is that old windows are usually the main source of thermal bridging, leaks, capture of sun heat and solar protection.
Depending on orientation and sunlight, you could install windows with low-emission-passive glass with Argon gas (it would be necessary to calculate the glass and transmittance of the carpentry through a Passive simulation).
As you may already know, in Barcelona you cannot change your windows without your neighbors (yeps, again your wonderful neighbors!).
Although surely some neighbors have already changed them without asking you, right?
So I don’t really know what to tell you about this neighbors issue.

In order to avoid leaks from heating and cooling of your home, it’s basic and necessary to have an airtight interior.
For this you can apply a layer of plaster on all surfaces.
As you probably already have a layer of plaster on the walls, you can apply another on the ceiling and a piece of walls under the false ceiling.
You should also apply a product that ensures airtightness at all encounters.
By encounters I mean floor-wall, wall-ceiling and wall-window.

With such air-tightness you’ll need to renovate air to get new oxygen inside your home.
This means installing a controlled mechanical ventilation system with heat recovery and bypass in summer.
This will make your home save so much energy!
You’ll get comfort temperature while fresh air, no noise from outside (no pollution, no pollen inside…) and safe money!
For the colder and hotter days, you’ll need to also install 1 or 2 ACs.
As your home is highly insulated and hermetic, you’ll just need to turn on the ACs in silent mode and for less than 2 hours a day to get in the comfort zone of 20-25º.
(May you be IceMen and need less temperature in summer, well, what can I say, there’s a global warming going on, so maybe you need to adapt to Earth).

My professional recommendation:
In our Architect studio in Barcelona we calculate the insulation and machines by doing a simulation with our specialized software recommended by the Passive House Institute.
If you don’t have money for everything, I recommend that you do those parts you can’t do later, such as: plaster on the ceiling, hermetic line in meetings and the ventilation machine tubes under ceilings (we do it from €700 + iva).
The rest and depending on your home layout, you’ll most probably be able to do it later.

You may also be interested in:
Our other post: Passive Ventilation System definition and price in Barcelona
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Hope this post ‘Sustainable Renovation Barcelona’ has helped you.
Best of luck on this adventure.
See you on the next post,


Founder of ERA architects 

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