1. Six questions in the right order
Each narrows the possibilities, and the order is substantive. The questions are asked in a fixed order.
| # | Question | Note |
|---|---|---|
| 1 | When the application is or was submitted | determines the applicable version |
| 2 | Whether the building is new or existing | two different regimes |
| 3 | If existing, whether this is substantial reconstruction | the definition comes from the regulation |
| 4 | What the intended use is, and whether there are several | several uses require a separate calculation |
| 5 | What the room-temperature area is | within the meaning of the regulation, not the register's |
| 6 | Whether an exemption or a relief applies | an exemption removes the requirement, a relief lowers the level |
Only then should the limit value be taken from the annex to the regulation in force. A value taken earlier may be wrong.
2. Why the date is the first question
Here is the practical core of the article, and one specific trap. The trap concerns the application date.
According to information published by the Ministry of Climate, updated requirements apply to buildings whose building permit application or building notice is submitted from the date of entry into force, and earlier requirements apply to documents submitted before it. The date belongs in the document.
The trap lies in the dating: some published materials give the date of entry into force as 1 March 2025, whereas entry into force was later changed to 1 June 2025. The date must therefore be checked against the legislation in force rather than against commentary, which may date from before the amendment. This is exactly the same pattern as in the building permit procedure.
3. What to check in the regulation
Four things no summary provides and none of which can safely be memorised. They must be taken from the regulation in force.
The applicable limit value, which depends on the intended use and, for houses, on area. The definition of substantial reconstruction, where the building is existing. The definition of room-temperature area, which differs from the area recorded in the building register. And the precise wording of the exemptions, where an exemption is relied on.
4. Buildings with several uses
A separate case requiring a separate calculation, covered by its own article. It concerns buildings with several uses.
According to information published by the Ministry of Climate, each use whose heated area exceeds 10 per cent of the building's total heated area is assigned the energy performance value corresponding to that use. The building's energy performance value is the weighted average of the parts' values by heated area, and the maximum permitted value is likewise a weighted average, calculated from the parts' limit values.
The weighted average must therefore be calculated twice: for the result and for the requirement. Doing it once gives the wrong answer.
5. The most frequent errors
Four errors all lead to the wrong requirement, and the first is the likeliest with an experienced designer. Experience can mislead here.
| Error | Why it happens |
|---|---|
| Reusing an earlier project's limit value | the values changed on 01.06.2025 |
| Using the wrong date | some materials name 1 March |
| Using the register's area | the regulation's concept of area is different |
| Assuming an exemption without checking | an exemption must be evidenced |
The first arises precisely from experience: anyone who has made similar calculations before trusts memory where the text has changed in the meantime. The requirements have changed in the meantime.
Summary and four practical rules
The applicable requirement is determined by six questions running from the application date to the plot's exemptions and reliefs, and only then is the limit value taken from the annex to the regulation in force. The date comes first because it determines the applicable version, and there is a common trap here: some materials date the 2025 changes to 1 March, whereas entry into force is 1 June 2025. In a building with several uses the weighted average has to be calculated twice, for the result and for the limit value.
Four rules: fix the application date before anything else. Check the date of entry into force against the legislation in force, not commentary. Take the limit value from the annex to the regulation for every project afresh. Use the regulation's concept of area, not the register's.
This article offers professional orientation as at the date of verification. It replaces neither the regulations in force nor the assessment of a competent specialist.