As we have explained more than once in our blog, Passivhaus refers to the concept of nearly zero energy buildings (NZEB) approved by the European Directive 2010/31 / EU on the energy efficiency of buildings. This standard is based on design criteria that allow the use of energy and natural light during the winter and the minimization of the solar incidence during the summer. Likewise, the high technical and constructive requirements contribute to the excellent thermal conditioning, conserving all heat absorbed in winter and dissipating in summer.
Its equivalent in the case of building rehabilitation would be the EnerPHit certification. In these cases, through the use of Passivhaus systems and components in these buildings, we can achieve a considerable improvement in the internal thermal comfort, durability of the structure, profitability and energy use during its useful life.
How can you certify as Enerphit?
One of these two criteria has to be fulfilled:
- According to heating demand requirement
- According to requirements of the individual building components: It must be demonstrated that all relevant elements and products fulfilled the criteria that the Passivhaus Institute has specified for certification. In case they are non-certified products, you must provide proof of the criteria reached.
In this link you can see the detail of the criteria calculations.
Why rehabilitate according to the Enerphit criteria?
The simplest answer is that the energy mortgage is reduced considerably, without having to rely on fluctuations in energy prices. These rehabilitations are prepared to save up to 75% of energy consumption.
Enerphit rehabilitation outperforms traditional rehabilitation in energy saving, but also brings other benefits to housing:
- Due to the mechanical ventilation systems of high energy efficiency, the indoor air of the homes is of high quality even in those located in the heart of the city.
- They are homes free of condensation (molds will not occur).
- They are well insulated homes, both thermally and acoustically, protecting them from outside weather and noise.
- It is a more comfortable home throughout the year.
¿And why certify?
By certifying, we can achieve more reliability because Passivhaus standards are guaranteed.
The sustainable materials and systems used are not very different from conventional ones, but these are based on greater energy efficiency based on the tightness of the property to save on air conditioning.
This certificate is intended primarily for existing buildings, which cannot be renewed until they reach the Passivhaus standard, given other conditions (economic, unattainable such as the orientation of the building, …).
How to qualify for the EnerPHit certificate? What is EnerPHit + I?
Normally, this certificate is intended only for existing constructions that cannot be renewed until the Passivehaus standard is reached, due to economic conditions (lack of profitability) or impossible work to be carried out (change the orientation of the building).
When 25% or more of the surface of the façade is rehabilitated with thermal insulation on the inside, the EnerPHit + I seal is designated.
We do certify an EnerPhit building
We are currently working on an Enerphit rehabilitation project in the Baix Llobregat region. It is a house of the early twentieth century, with stone walls and covered with wooden beams, among others.
In the current phase, all the partitions, pavements, existing stairs, torn up facilities and removal of debris have already been demolished, leaving only the initial structure of the house, beginning to dress again, initiating the installation of screed insulation. This has shown that heat loss can be further reduced through the building elements adjacent to the ground. This thermal insulation can have different thicknesses, in our case we are talking about an XPS type insulation of 10cm in screeds and facades, and 20cm in roof.
Different thicknesses of XPS Polystyrene
The challenge in this insulation will be to comply with the “marker pen rule”, that is, to keep the thermal envelope without discontinuities so that a continuous line can be drawn without lifting the marker. What is sought with this is to minimize the thermal bridges starting from the first moment until the end of the insulation, since these can alter the energy performance of our building.
In order to ensure that the work is carried out correctly following the criteria necessary for future certification, we have several professionals within our reach. On the one hand, we have among us a Tradeperson certified technician, who assures us that everything is executed following the requested standard (more information here), and on the other hand we have the advice and audit of an external technician (Designer PH) who corroborates through the necessary calculations in the different audit phases.
Our forecast is that in a few months we can request the Enerphit certification, with results well below the mandatory markers:
It is important to keep in mind that the values are provisional and that they are being adjusted so that from the heat recovery system and with a post-treatment battery the internal thermal needs can be covered on most days of the year.