To certify or not to certify, that is the question.

Passivhaus is a building standard that guarantees a building with high energy efficiency and increased thermal comfort. To achieve this, it is necessary to follow a series of steps, the last of which is the in-situ test to obtain Passivhaus certification.

But is it compulsory to certify a house built under the Passivhaus standard, what are the advantages of certification and what does this certification imply?

We know that these are common doubts that arise when you are thinking of building a Passivhaus, and that is why I have dedicated this article to answer them, let's get to it!

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What is Passivhaus certification?

Passivhaus certification is a quality seal that guarantees that the house or building satisfactorily meets the criteria of the Passivhaus standard. The basic requirements are as follows:

• Heating demand less than 15 kWh per m² of floor area per year.
• Cooling demand less than 15 kWh per m² of floor area per year.
• Primary energy demand less than 60 kWh per m² of floor area per year.
• Airtightness less than 0.6 air changes per hour.

There are 3 categories of Passivhaus certifications: Passivhaus Classic, Passivhaus Plus and Passivhaus Premium. You can read more about them here.

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What is the process to certify a Passivhaus house?

The Passivhaus Institute is the body in charge of certifying Passivhaus buildings. This certification can be carried out either directly by Passivhaus Institute staff or by an accredited certifier (not to be confused with a certified Passivhaus designer!).

Although in theory, certification can be requested after the work has been completed, it is highly recommended to contact the certifier at the initial planning stage, because in this way any problems can be corrected more easily.

In general, the steps to obtain Passivhaus certification are as follows:

1. Initial check: The certifier must check whether the project has special characteristics in order to determine how it should be assessed during certification.
2. Preliminary review: In this phase, the design concepts, insulation and installations are evaluated in general terms. The preliminary version of the calculation of the Passive House Planning Package (PHPP), a specialised software for planning the energy efficiency of a building, is also reviewed.
3. Project phase review: Before construction starts, all project documentation related to the energy balance, the technical data of the building materials and the complete calculation of the PHPP programme is handed over to the certifier. The certifier will report if everything is correct or if adjustments need to be made.
4. Final review: Once the construction work has been completed, any changes that have been made will be updated in the final version of the documentation to be submitted to the certifier. An on-site test known as the "blower door test" is also carried out to measure the tightness of the construction.

If all certification requirements are successfully fulfilled, the owner will receive a certificate with a unique identifier number, a supplementary booklet containing the documentation with the energy balance and all characteristic values of the building, and a plaque (optional).

Is it compulsory to certify a house built to the Passivhaus standard?

The answer to this question is no, it is not mandatory. As I indicated at the beginning, Passivhaus is a construction standard to achieve a building with superior energy efficiency and unparalleled thermal comfort.

To meet the Passivhaus standard criteria, good insulation, the use of high-performance windows, the elimination of thermal bridges, the incorporation of a mechanical ventilation system with heat recovery and a high level of airtightness are necessary. A certified Passivhaus designer, or an architect with the support of a Passivhaus consultant, can design a house that meets these characteristics.

That said, even if your home is designed and planned to meet the Passivhaus standard, ultimately certification is the only process that guarantees that it has been implemented correctly.

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Advantages of Passivhaus certification

There may be various reasons why you may decide that it is not necessary to certify your Passivhaus home, and this is completely valid, but I would like to discuss some of the advantages that you can gain by certifying it:

• Quality assurance. With certification you can be sure that the Passivhaus standard really will be achieved in your home, and you can avoid possible fraud by companies that want to "sell you a pig in a poke".
• You will have supporting documentation to apply for the so-called "green mortgages", which are mortgages that reward sustainable and energy-efficient housing with better conditions. Here is a link to this article with more information on green mortgages.
• During the certification process, the certifier may detect energy saving measures that would be too costly to implement and are not necessary to comply with the Passivhaus standard.
• It will increase the value of your home. If you want or need to sell your home in the future, this certification is a guarantee of quality that increases the value of your home in the real estate market.

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Finally, I come back to the initial question: To certify or not to certify? After my research, my answer is that it is worth certifying. If you are already investing a little more in building an energy efficient house, the cost of certification is not much higher, especially if you consider that you can apply for mortgages with better conditions and that you can sell your house at a better price, if by fate you want or have to do it. No one knows what the future holds!

But if you decide not to certify your home, don't worry! You will still have an ultra-efficient and comfortable home, and you always have the option of doing so in the future. Although it is not recommended, remember that you can still apply for Passivhaus certification even after construction is complete.

So, I think we have solved this question, and if you want to take the next step towards your new passive wood house schedule a video call with us and let's start shaping your project.