What windows to install for your Passive House?

In this post ‘Different passive window systems’, I tell you about the 3 passive window systems that you can install in your passive house, their advantages and disadvantages. Additionally to informing you, we recommend the window materials that we believe are best for your home.

In case you still don’t know us, let me introduce our studio: we’re ERA architects, the English speaking green architecture studio to call in Barcelona.
Actually, I’m Esther Rovira, an architect in Barcelona and a passive house designer for new sustainable builds and big green renovations in Barcelona and Catalonia.
In this post you’ll find all the essentials from our professional point of view.
I hope this helps you!

I hope this post helps you!


1) Aluminum
Although there is a wide variety of aluminum windows with thermal break and even certified for Passive House; this option doesn’t convince me (for now).
Aluminum is a material with high thermal transmittance (that is, it highly transmits temperature from the outside to the inside and vice versa).
In our Passive Houses we try to separate the outside temperature and the inside temperature as much as possible and aluminum naturally doesn’t offer us this quality.
In order for an aluminum carpentry to meet the levels of insulation that a passive house needs, insulating chambers, foams or rubber are added.
This increases the dimensions of the carpentry to a minimum of 110-119mm.

2) Fiberglass
Thermally it’s better than aluminum but it is not even close to the thermal performance of PVC. This material is almost 10 times stronger than PVC and much more stable (with less expansion and contraction).
They are usually wide (105mm in lower folding) and have a very high durability.
There are only 8 manufacturers of these carpentry in the world and 6 are located in China.

3) PVC
Right now the material with the best thermal performance and value for money is PVC windows.
In other words, it’s  your most economical and thermally insulating option.
Even so, you should know that it is an unassuming material with large carpentry (101mm in lower casement) and pre-frames that don’t allow large openings.
It’s also important to emphasize that PVC is Polyvinyl Chloride and like all polymers, its base is petroleum (normally more than 40%!).

4) Wood
It is the most consistent option because wood is naturally insulating.
Despite the fact that they usually have thick thicknesses (117-121mm in lower casement), today you can find very minimal carpentry models (98mm in lower casement).
The only two drawbacks are: its price and its maintenance.
You can avoid maintenance with mixed carpentry of wood with aluminum on the outside and wood on the inside.
If normal wooden windows are expensive, the mixed ones are even more unaffordable.


My professional recommendation:
In our Architecture studio in Barcelona we always recommend wood or PVC carpentry.
If you do not have a budget for wood and you are in a city with a warm-temperate climate, directly ask for a budget for double-glazed PVC windows with low passive emissivity.

You may also be interested in:
Our other post: Types of Facades
Or know that if you subscribe to our newsletter of recommendations for your passive house or positive house; You will receive useful information and you will be able to opt for discounts on our services.
And of course you can unsubscribe whenever you want!


I hope this post ‘Passive House passive windows’ has helped you.
Best of luck on this adventure.
See you on the next post,


Founder of ERA architects 

P.S. Wanna get FREE tips for your project weekly? Yas! or follow us on Instagram, Pinterest, Twitter y Facebook