A few fallacies regarding Passivhaus Passive Houses

You may have got the opinion in previous posts that I am against Passivhaus Passive houses, nothing could be further from the truth; I see the Passivhaus standard as THE way forward in creating a house with the lowest energy demands.

This post is in response to a tweet by the Passive house guru Wolfgang Feist (http://www.passive.de and @WolfgangFeist) lamenting the misinformation being spread regarding Passive Houses and asking “Why is it so important to keep up poor energy efficiency (for some people)?”.

Well, as an architect trying to convince clients that this is the way to go, I frequently come up against a range or arguments (fallacies) against Passive House concepts and below is the fallacy against the truth:

1. I’d hate to live in an airtight house, won’t I suffocate ? – FALSE

It is the uncontrolled air leakage (draughts at back of neck when sitting on sofa) that are one of the biggest contributors to energy loss in a house. By creating a completely sealed house you are at risk of creating internal condensation problems (I doubt if you’d suffocate however); so how do we get fresh air (that is essential) into the house? This is achieved via a mechanical ventilation system that purifies the air (you are therefore getting a purer air than simply relying on trickle vents in the windows or hit and miss vents in the walls.)

2. A Mechanical Ventilation system ? I don’t like the sound of that !

You won’t notice it, the units nowadays are silent in operation, you won’t feel any blasts of air and as described above will create a purer, healthier air in your building.

3. A Passive House costs a lot more money ! – FALSE

The amount of insulation required and the type of windows etc is probably what you were going to get anyway, as Building Regulations (in Ireland at least) are rapidly approaching Passive House standards anyway. The cost of certification is probably the smallest outlay to ensure that your house is built correctly.

4. I can’t get the materials that are required – FALSE

Even living in a remote part of Ireland, I am able to obtain all the insulation,membranes,tapes and seals etc. that are required thanks to excellent builders merchants such as Glynnes (Claremorris), Archers (Ballina) etc…

5. I don’t want a boxy design – FALSE

The Passivhaus calculations (PHPP is the software) is a very flexible tool that can work any design. Obviously the design will influence the results in PHPP but it is the designers skill in creating an architectural design that fulfills the Passivhaus construction standard.

6. I don’t believe Passive Houses works ! – FALSE

There are countless houses across the world (with happy clients) across the world in varying climates (including Ireland) that can attest to the success of their house in all weather conditions (including the sub-zero temperatures currently being experienced)

7. I’d hate to live in a house where I can’t open a window ! – FALSE

There’s nothing to stop you having opening windows and opening these at any stage of the day!

8. I’d hate to live in a house without a fire! – FALSE

There’s nothing to stop you having a fire in your house; the best way to achieve this would be to have a your fire as a sealed, multi-fuel/wood pellet etc. type stove that acts as a back-up heating system with an air intake from outside.

I’ll probably add more to this post as the fallacies are encountered, comments as always welcome and if anyone encounters others, let me know and I’ll include them in list. And if you think I’ve got anything wrong, also let me know!

0 thoughts on “A few fallacies regarding Passivhaus Passive Houses

  1. Hi. I was just wondering what happens if the MVHR unit breaks down or there is a power cut. Do I have to run round opening all the windows to make sure there is enough breathable air? I’m sure this is an issue that has been raised before but I can’t quickly find an answer and I just wondered if you know.

    1. A passive house is never completely air tight (threshold is 0.6ach) so you'[d have enough air to breath (someone correct me if this is wromg!); the house may get a bit stuffy and there’s be condensation on windows etc.. inside after showers etc.. but opening 2 windows opposite each other to provide cross ventilation will normally change the air completely in a room within 10 minutes.

    1. Excellent, I’d advise getting someone to work alongside your architects (unless they know PHPP) as a Passive House consultant that can check the house in PHPP as you progress, the website you mention should have listing-there’s also an EU passive house site too that may help.

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