Monday, 14 November 2011

Assignment no. 1 - Passive Houses: Achievable concepts for low CO2 housing

This paper, entitled " Passive Houses : Achievable concepts for low CO2 housing" was written in January 2006 by Henk. F. Kaan and Bart J. de Boer of the  Energy research centre of the Netherlands. The paper was presented at the ISES conference 2005, Orlando, USA in September 2005.
In January 2005, an EU supported project (involving nine countries) called Promotion of European Passive house(PEP) commenced to promote passive house development based on the German/Austrian model. This paper examines the issues that the PEP project relates to. 
The main points of the paper are:
  • There is a need for more energy efficient buildings because "in the Western world, 40% of all energy consumption is from building".
  • Germany and Austria are the front runners in passive house construction with over 5,000 passive houses  built to date and more to follow.
  • Some European countries are introducing passive house initiatives but shouldn't just copy the German/Austrian model. Climate, building tradition, specific building codes and building details differ from country to country and this affects design and construction.The economics of passive house building vary from country to country.
  • The PEP project must define the term Passive House for each country. The writers inform us that "The energy use in an absolute sense does not by definition tell whether the building is good or not". One must question that achieving a passive house shouldn't in all cases be based on energy usage of 15KWh/m2 but based on different criteria for different countries. For instance in warmer countries in southern Europe, shouldn't energy required for cooling be taken into account?
  • The behaviour of occupants is also a huge factor once the house is built. For example, mis-use of the heating and ventilation system leads to over use of energy. The writers ask should the passive house technology "take over the decisions?" and systems be designed as "fool proof". 
  • While solar energy is important, it is the overall combination of the heating elements in the building that contribute to satisfactory indoor comfort. These heating elements include: air tightness, heat recovery from ventilated air, insulation building type and shape. These elements were found to be the most important when the energy research centre of the Netherlands used the computer program "TRNSYS" to carry out a study on optimum use of solar energy in building.
The paper concludes by the writers assuming that every country has different characteristics. The PEP hopes to look at all the countries involved and find similarities and differences "and show how the countries can learn from each other."
I agree  that every country has different characteristics such as climate, building traditions, access to building materials and passive houses should be defined differently in different regions.
 Also, in countries where the concept of passive house is in the early stages, it is more difficult to obtain the relevant building materials. These may have to be imported and one then has to consider the carbon footprint disadvantage and cost of the passive house option.

Note: Click on this link to go to the PEP website for more information:

Note: Here is a visual presentation showing the basic principles of  Passive House construction


  1. Here is a link to the original article;

    Building passive houses in other countries is clearly not a matter of straight forward copying the German concepts. For the building tradition, architecture and building technologies differ from country to country. In Germany, for instance, outer wall plastering is quite common, whilst in Belgium and in the Netherlands brick cavity walls are mostly applied, and Sweden and Finland have broad experience with wooden buildings. These three various construction methods ask for different constructional solutions.

    The definition of a passive house should therefore be different for each country or climate and the model will need to be adapted to suit.

    On an side note; its interesting to learn from the article that the word passive house actually originated from the US in the 1970's.

    On Anthony’s blog post he mentions that people may be put off by the cost of building a passive house however the PEP project has found that the extra costs involved for insulation etc will be compensated by the savings made in heating output costs.


  2. Hi Shay,

    interesting blog post. While I agree with the fact that different countries build with different materials and have to handle different climatic conditions, I don't agree with your statement that a different way of measure should be applied in different regions. A standard is a standard and should remain the same. Surely, there are different challenges to be met, but what wise construction in the north of Europe can save in heating requirement, should another way of wise building practice save in cooling requirements in the south. What do you think?

    In addition, I think it does not matter if you build in timber or concrete, using plaster or brick. Every country looking at the passive house concept has an advanced building standard and should therefore be able to adopt to energy efficient construction.

    However, there are numerous possibilities of achieving a low energy building and local legislation should adopt to a reasonable level for its residents. "Passive House" is just one way of aiming for energy efficiency through good building practice but it has not necessarily be "the only way".

    I think passive house is just showing best building practice with its concept of orientation, using solar gains, air tightness and good insulation. It is not solely about meeting energy consumption thresholds and u-values or to sell a specific range of products.

    As you also pointed out in your post, final energy consumption is about consumer behaviour. Keep up the good work. Wanna watchmeblog just follow:

    Kind regards,

    passive attack

  3. Hi PassiveJanGMIT,

    did you not know that all the good things in live come from the US first? :)

  4. Shay,

    Firstly I find that in the Western world, 40% of all energy consumption is from building quiet staggering and never thought that the figure would be so high!

    I agree with you that different regions should be defined differently when talking about passive houses because of different cultures, landscapes and climates.
    I think the cost of building a passive house should be looked at in more depth by the PEP as different countries differ in terms of labour costs. I may be alot more cost effective to build a passive house in Germany, as competition for the contract would be alot more competitive there because it is likely that alot more companies are building passive houses in Germany as opposed to Ireland. The issue of skill, training and awareness in constructing passive houses is essential for obvious reasons and I think more emphasis should be put on this.

    Good report, fair play.

    Kieran McNicholas

  5. @Passive attack,

    Of course there will be different methods of achieving the passive house standard in different countries. Its simple cold countries will require more passive gains while a hot country will require cooling in the warmest seasons.

    There in no doubt that a passive house model cannot be carried from country to country because of different building methods, climates etc. As long as the final goal is a passive standard then there will always be different ways to reach that goal. Good workmanship, proper installation and best practice will help to achieve this.

    Look at the Denbydale project, no two porjects will be the same, even if they are in the same country. You cannot apply one model across the board as it simply will not work.


  6. @passivejanGMIT,

    Fair comment about the solar gains.
    I can see that you know your stuff. Passive housing is an interesting concept. We'll see what coming up in the near future..I think there is a lot to come.

    passive attack

  7. Hi shay

    I agree with your with you that different countries build with different materials, this perhapse could be due to the price of materials in different countries. even though t climate conditions vary I thisk once a standard has been set it should stay the same in all climate conditions.
    passive houses are being built in all countries and the end result is the final energy consumption which everyone wants to achieve no matter what climate conditions exist.

    good work.

  8. Colleagues,

    Thanks for your posts.
    But consider the following – a house in northern Scandinavia and a house in the Mediterranean. There is no way you can compare them. There would be massive differences in outside temperatures. The Mediterranean house would use energy for cooling, which is more than the energy required for heating. This house would also try to minimise its solar gain in terms of orientation and window frequency. Shading would be required in the warmer region? Would the insulation type be different to minimise the cool air escaping to the outside? Surely in this case, these countries have to define their passive houses differently. As Jan said, as long as every country strives for a passive standard, there are different ways to reach that goal


  9. Shay,

    You are right and its the same point I was making in my first post.

    A model cannot be copied from one country to another. Even within countries the model cannot be copied. A house down in Wexford vs a house built in Donegal will possibly have different design details because of the macro climate present in each area.

    From reading the article and all the comments again i think its safe to say that we all have concluded that each design will differ from country to country but that once the passive house standard is the goal then that is the main thing.

    Good job shay, your blog has generated alot of interest :-)


  10. Comment Part 1


    I wish to comment firstly on the quote: "The energy use in an absolute sense does not by definition tell whether the building is good or not". If you are trying to have a low energy building, surely the energy use is the only definitive way of measuring whether you have achieved your aims or not? I find the arguments put forward by Kaan and de Boer to be lacking consistency.

    I think that this may be due to the fact that this publication is quite dated. I notice that the citation on the article you have summarised is for the year 2006. At this time the Passive House standard was very rigid and not well travelled. In 2007 a new Passive House Planning Package (PHPP) was released which was updated and dealt with many of the issues mentioned. At the time of publication, as mentioned, Germany and Austria were the leaders in the Passive House movement with 5,000 houses. So of course they would not have considered peak cooling load. This has changed considerably in the past five years. Although they are still the leaders in the movement, the standard has travelled throughout the world, including the US. The PHPP has now been updated to include summer comfort and cooling, and the following:

    The new calculations introduced into PHPP 2007, developed within the context of Passive-On are:
    - Solar loads through opaque building elements
    - Night ventilation
    - Monthly method for cooling
    - Overheating frequency
    - Peak cooling load
    - Latent load
    I have attached an image to my blog of the Passive House Criteria and the verification sheet for the PHPP to illustrate the required heating and cooling loads to comply with the standard. (I am not able to attach it as a post so had to put it there!). In this you will see that useful cooling demand is specified as < or equal to 15kWh/(m2a). This deals with ventilation and cooling demand. The excess air temperature is also a good measure of building performance in terms of maintaining a constant temperature and internal comfort. Also the production of Passive House building materials has become more widespread since 2006. Even an Irish company, Munster Joinery, is now manufacturing passive windows, and there are numerous passive house construction companies in Ireland.

  11. On another note, the term “Passive House” is not a protected term. It is defined in the article as "An (ideal) passive house heats and cools itself in a purely passive way" [Adamson 1987, Feist 1988]. If something is called a “Passive House”, this does not ensure that it is meeting the defined “Passive House Standard”. A house that is orientated towards the sun, but does not take any low energy measures can be called a passive house. If a house is to be guaranteed as meeting “Passive House Standard”, it needs to be certified by the Passive House Institute in Darmstadt as meeting the standard, and will be deemed a “Certified Passive House”.
    The arguments that were put forth by our colleagues are both very compelling. I agree with Henrik’s comment that a “standard is a standard”, and do not think that the Passive House criteria should be changed for each country. If there is to be a standard it should be universal. I also think that Jan is right and that all other countries shouldn’t just blindly follow and copy the standards dictated by the Germans!

    I was intrigued by the question posed by the authors: “Which principles of solar building should prevail?” So I propose a compromise. In essence I agree with the Passive House standard. I think the aims are commendable, but that some of the requirements are too rigid. I propose that the criteria for the heating energy demand, useful cooling demand, primary energy demand, and excess temperature frequency are the only determining factors as to whether a building meets the standards or not.
    At the moment, if a designer wishes to use windows that are not Passive House certified, or to use a construction that does not meet the required U-values, they have to write to the Institute stipulating reasons for this and the Institute can decide to accept or reject the building as meeting the standard. I propose that the specification of U-values, g-values, ventilation efficiency etc. is stopped, and that the criteria I mentioned previously are the only specifications for the standard to be measured against. This means that the standard is consistent across all countries, but that designers across different climates have the freedom to approach the standard in whatever way they wish.

    Note: This is the first time I have come across the PEP. Initially I understood that they proposed to create a different PHPP for each climate but I see that they have compiled a database of all of the publications on Passive House by each country. That is a great help, and will definitely be of use in the future, thanks Shay!

  12. If you look at the SEAI Passive House Guidelines document for Ireland the standard for the U-value for the walls is < or equal to 1.75 W/(m2lk) and for roof is < or equal to 0.15 W/(m2lk). This is higher U-value then specified for Germany, which is a positive step. I still think that the recommendations for U-values should be relaxed, as even this standard is still difficult to achieve, and not necessarily necessary in Ireland.

  13. Interesting article Shay. I found the energy consumption of 40% to be very shocking, I didn't realise it was so high. This article is very consistent with other ones I have read about the development of passive houses in different countries with different climates. Clearly Ireland's high winds and constant rain is a major concern when designing here as a pose to the dry hot deserts of Nevada which were mentioned in Jan's blog.

    I look forward to your next blog.