1. Where to find the current class
Three steps, and the second contains an important distinction. It concerns calculated and measured certificates.
| # | Step |
|---|---|
| 1 | Check in the building register whether the building has a valid energy performance certificate |
| 2 | Check the type and date of the certificate |
| 3 | Where there is none or it has expired, order a new one |
The certificate for an existing building is based on actual consumption data and is valid for ten years, while that of a building being designed is based on a calculation. The baseline for a renovation is the first of these, and the difference between the types of certificate is covered in a separate guide on building energy performance.
2. Why it is the baseline
Three reasons all concern the support, and the third determines the volume of work. The baseline class sets the class gain required.
Partial reconstruction requires at least a one-class gain, which cannot be measured without a starting point. According to professional sources, support is not available where the building already has the best possible class. And full reconstruction requires class C, for which the current class says how large a gap has to be closed.
Going from class F to class C is a different project from going from class D to class C. The current class is therefore not a document but an input parameter of the design.
3. What it does not tell you
Three things must not be inferred from it, and the second matters most in practice. The class does not say which works are needed.
| What it does not say | Why |
|---|---|
| Whether the building is technically sound | the class measures energy use, not structures |
| Where the energy is lost | the class is an aggregate indicator, not a diagnosis |
| Which works are needed | the same class gain can be achieved in different ways |
The class says that the building consumes a lot, but not whether the cause is the roof, the windows, the ventilation or the heating system. That answer comes from a technical survey, as covered by the article on technical condition: the class says how large the problem is, and the survey says where it is.
4. When to order a new certificate
Three situations, and the third is common in apartment buildings. The certificate is often out of date.
Where there is no certificate. Where the certificate has expired. And where the building has been substantially altered in the meantime, so that the old certificate no longer describes the present situation, for instance where the heating system or some of the windows have been renewed.
When ordering a certificate the competence of the specialist must be checked, which is covered in a separate guide on energy performance. Competence can be checked in the register.
5. What to do if the class is surprisingly good
One situation that causes disappointment, and whose remedy is to reframe the question. The question has to be put in numbers.
Where the building's consumption has been low, the class may be better than expected, and a better class means the required gain is harder to achieve. That does not make the renovation pointless: it means the share of support may be smaller or the conditions stricter.
The professional recommendation is to assess the renovation without support as well, since the indoor climate, the life of the building and the running costs improve regardless of the funding. The benefit remains in that case too.
Summary and four practical rules
The current class is found in the building register, and the baseline for a renovation is the certificate of an existing building, based on actual consumption data and valid for ten years. The class is an input parameter of the design, since the size of the required gain and therefore the volume of work depend on it, but it does not say whether the building is technically sound or where the energy is lost. A surprisingly good class makes the required gain harder, which does not make the renovation pointless but reduces the share of support.
Four rules: establish the current class before commissioning the design. Use the certificate based on actual data rather than the calculated one. Do not read the class as a diagnosis, since it does not say where the energy is lost. Check the age of the certificate where the building has been altered in the meantime.
This article offers professional orientation as at the date of verification. It does not replace the conditions of the body granting the support.