Why we decided to base our house on the Passivhaus Standard

Three years ago we decided to embark on a crazy adventure to do a self-build[1]. In the beginning we dreamt of a double story house with double height ceilings in the living room and various other design details. But since then we have simplified our ideas and have finally decided on a rectangular, one story house of 140m2. Although the design changed, the complexity increased because we decided to build a house with as low energy consumption as possible (a near zero energy building), that still ensured a good level of comfort all year round (without blowing the budget on heating costs) and reduced our environmental footprint to a minimum.

Rodrigo is the person in our team that has spent many long hours studying the Passivhaus concept and in 2016 he participated in the first Passivhaus Certification Course held in Chile (lead by architect and PhD Marcelo Huenchuñir Bustos).

In the last few years I have learnt a thing or two from Rodrigo about this building method. At least I now understand a few of the key concepts such as insulation, air infiltrations, thermal bridges or how a heat recovery ventilation system.

But, in order to give you an idea on the main characteristics of a Passivhaus and why we have decided to use this standard for our project, this first post is an interview with Rodrigo:

1. What is a passivhaus?

It is an energy efficient, ecological and healthy house that offers a comfortable temperature throughout the year, with only 10% of the energy consumption of a conventional house.

The Passivhaus Standard was developed in Germany more than 30 years ago, and takes into consideration the following key elements:

  1.  High leve lof insulation
  2.  Orientation towards the sun in order to maximise natural light (free energy)
  3.  High performance windows
  4.  A design free from thermal bridges
  5.  An airtight construction
  6.  Uses a heat recovery ventilation system

Don’t worry if all this sounds like Greek at the moment. Over the next few months we will go into more detail on all of these concepts as we build our house. And we will show the practical application of each element.


2. What are the benefits of building using this standard?

COMFORT: The inside temperatura is always within the comfort range of 21-25 degrees Celsius (winter and summer). A passivhaus provides stability to the temperature in the entire house, each hour of every day. It reduces heat loss in winter and heat entry in summer. It also ensures that the temperature is uniform in the entire house. No more going to the bathroom in winter and feeling like you are entering a freezer!

ENERGY EFFICIENCY: They are houses designed and built to be highly efficient in energy consumption, with the potential to use up to 90% less energy that traditional houses. This translates into important savings on heating and cooling costs throughout the year.

REDUCTION IN CO2 EMISSIONS: due to the low energy consumption, CO2 emissions are also 90% less than in traditional houses, thus helping to mitigate climate change which is THE challenge we are facing as humanity in the 21st century.

NATURAL LIGHT: with the right orientation (towards the north in the southern hemisphere), the house makes the most of the sun’s energy and natural light, without overheating in summer.

HEALTHY AND QUIET: the ventilation systems installed in passive houses provide a constant supply of fresh air, thus ensuring that contaminants and odours are eliminated from the house, while maintaining a comfortable interior temperature. The insulation and high-performance windows also make the house really quite.

A VERT GOOD PAYBACK: the additional costs of a Passivhaus vary depending on the country – is believed to be between 3% and 10% above the overall price of a house. But when considering the savings in energy costs during the life of the house, the unprecedented thermal comfort and a drastic reduction in emissions, the initial extra cost is paid back very quickly.

3. What are the challenges to building a Passivhaus in Chile?

Complying with the strict performance standards to achieve the Passivhaus certification is an enormous challenge and so far there are no houses built in Chile which have received the certification, although several have used the methodology. The main challenge is achieving the required level of airtightness. This implies having a workforce with a high level of knowledge and skills, which basically do not exist in Chile.

____

Over the next few months we will go into a lot more detail on all of these concepts as we implement them in our house. But it is important to stress from the start, that we are not experts in this type of building and this is the first (and hopefully last) house we will build. But we are passionate about sustainability and making as little impact on the environment as possible. And if it saves us money in the long run, then even better!

Hopefully you will keep following us throughout our challenge to build our Passivhaus…


[1] A self build does not actually mean you are the one building the house. We have a construction company, but we are responsible for the design, costs, timeline etc. This is a concept especially used by banks when a person is financing the building of the house and not buying directly from a construction company/real estate agency.

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