Passive House: 10 questions to John Sasso

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1) First question: which way forward for the design of a passive house?
To design the passive house standard in energy efficiency must be strongly and simultaneously work on two tracks: on one hand we need to drastically reduce losses, while the other must be increased in a controlled manner free from outside the solar gains.
I purposely specified “in a controlled manner”, as typically the contributions of heat from sunlight coming from the glass surfaces. Now: the windows in a passive house is the real element that dissipates heat.
We think that in a glass house very efficiently disperse heat ten times more walls, so they are both the largest source of heat, but also the worst source of dispersion.

2) must be designed so as the windows of a home energy efficient?
To solve the mystery to be put in the windows so that it maximized the contribution winter. This is achieved through a clever study of bioclimatic design that influences the number, position, orientation and shape of the glass surfaces. Sometimes the result is not achieved the desired standard passive without the right combination of windows.
In the discussion of this limit ourselves here only to the winter issue of its liability standards, and we know that that standard is in temperate climates is frequently accompanied by problems of overheating in the summer, if not carefully evaluated corrective.

3) The design of a passive house course provides a total isolation of the outer casing; what exactly?
Even here the theory is one thing, practice another. The way to proceed with the positioning of the insulation varies depending on the location climate of the intervention. In hot climates will tend to reduce the insulation against the ground to exploit the natural geothermal cooling summer offered by the soil. In cold climates the insulation goes almost without difference around the entire enclosure.
Crucially, there are gaps in the insulation. Verification can do that by following the perimeter of the housing marking the insulation with the stroke color. If these breaks are to be resolved with appropriate solutions.

4) What choice do to build a passive house?
It ‘like saying “Which house is better?” the univocal answer does not exist.
I always tell my clients: do not worry that it is passive or not: if you’re worried well.
On the surface it seems a contradiction, in fact people are anxious dala run at all costs to save energy at the cost of losing the pleasure and comfort of a home comfortable and welcoming. A house-to-be I said MUST risparmiosa. But it should please his owner. Only if you like and meet the emotional needs of those who lived, loved and will be preserved. If it is risparmiosa, but do not like, can be an efficient machine, but at the first change of the situations will be neglected in search of a better response.

5) There is a section for best passive house?
The answer depends on how much the geographical area or climate where the intervention is made. In all climate zones where the daily summer temperature (average day-night) rises above 25 ° C on the housing package should be split, keeping a layer of “heavy” high thermal inertia, on the inside, and putting the ‘ insulation on the outer side.
This is because whenever the outside air temperature rises above 25 ° C according to standard ventilation and we do, then 0.3 to 0.5 volumes per hour, means that in 2 or 3 hours we changed the internal air with the external one.
25 ° C outside air heat add the data from people (100W thermal / p) from appliances, lighting (97 watt heat lamp for a 100W incandescent), the sun beating through the windows.
At this point the internal temperature can rise by up to much above 25 ° C that are considered the temperature threshold for the comfort. The only thing that can save us is the ability of the casing on the inside to absorb heat!

6) There is legislation passive house?
The passive house standard (or Passivhaus) is encoded by the Passivhaus Institut Dr. Feist in Stuttgart in 1991 and if you want to obtain the relevant certification must refer to that protocol. Per se instead the term refers to every type of home dimensioned in such a way as not to necesitare of a heating system traditionally interso, for winter heating.

7) There is no software to build a passive house?
We have many, many usarne and attention to! The objective of Passivhaus is to maintain the maximum thermal load winter within the limit given by the quantity of heat generable without a plant of climatizzaione traditional (example integrating the heat in the air flow of spare part if is presete a ventilation system controlled) and contain the annual requirements under 15 kilowatt hours per square meter per year (15 kWh / (m² * a). To get it we need to make an accurate analysis for solar glass surfaces. To reduce overheating in summer must calculate thermal inertia of the housing and and in particular ammittanza internal (with simple words: the ability of the casing on the inner side to absorb heat). etc. …

8) What is the difference between a Passivhaus and casaclima?
They are two different things. Passivhaus is a specific and unique energy standard encrypted private in 1991 by Dr. Feist of the Institut Passivhau. According to the Protocol for the intervention or be certified or not.
Casaclima is a protocol for energy certification valid only in the Alto Adige, but commercially recognized in the rest of Italy. Casaclima certification means that the building has been validated according to this protocol, after which it can be class A, B, C, etc..
I omit here to dwell on whether or not to refer to Italy in a protocol designed for northern European climates, so it treads much emphasis on the importance of solar (which not surprisingly does not belong to the European building culture) and says nothing on the mass and inertia of the casing.

9) Standard Passive and green building get along?
This is clearly different instances. In the first case the aim is specifically build homes with low energy consumption, in the second case in their realization respected man and environment.
As always, the results can be concurrent or not. It depends on the designer.

10) What facilities for passive house?
The first objective is saving. The expenditure for the isolation not fair-and appropriate-the casing can also be very high, depending on the cost of the insulators employees. It ‘clear that isolation should not be spared, as it enables us to reduce consumption then. The goal is to isolate so much to not have to make your heating system and save it on a very firm voice. The impantistica you thus solves in the exhaust system and sanitary hot water. Will serve to produce than the minimum integration of heat needed something simple, very variable according to the specific situations.