1. What a nearly zero-energy building means
According to professional sources the definition has three parts, and the third makes the whole difference. The third concerns renewable energy.
| Part | Content |
|---|---|
| 1 | a technically sound and energy-efficient building |
| 2 | built to the best available construction practice |
| 3 | using renewable energy technologies |
The third part distinguishes a nearly zero-energy building from one that is merely well insulated. The requirement is therefore a combination: reduce the demand and cover the remainder with renewable energy generated on site.
2. The two levels and how they differ
According to professional sources the requirement operates on two levels, and their order is substantive. The first level is a limit value.
| Level | Condition |
|---|---|
| Lower level | must be achieved without using renewable energy |
| Higher level | must be achieved with renewable energy |
The most important practical consequence follows: renewable energy may not replace the building's thermal performance, it complements it. Solar panels cannot compensate for poorly insulated external envelopes, because the first level is checked before they are counted.
The specific limit values for both levels must be taken from the annex to the regulation in force, since they changed on 1 June 2025. Older values age quickly.
3. When the lighter requirement applies
One exception follows from the building's location rather than from anyone's wishes, and it is the least known part of this article. The exception is narrowly worded in the regulation.
According to professional sources the lighter level applies where a building does not have enough roof area facing the sun and unshaded by other objects to install a solar electricity system of the capacity needed to reach the nearly zero-energy level. In that case the new building's energy performance value must meet the low-energy building requirements.
The observation is important and counter-intuitive: the orientation and shading of the roof affect not only the solution but which requirement applies, as covered in more detail by the article on solar energy and roof area. The exception must be evidenced rather than assumed, and its conditions must be checked against the regulation in force.
4. What it means for design
Three consequences, the last of which bears directly on the budget. They concern the design and the plant.
The siting of the building on the plot becomes an energy question rather than only an architectural choice, and the roof shape and shading must be assessed early, since the applicable requirement may depend on them. It is decided in the first phase.
The renewable energy solution is not an addition but part of the requirement, and it cannot be dropped selectively later. A solar electricity system is not an optional extra in this context, and it belongs in the budget under requirements rather than wishes.
5. What changed for houses
A significant extension that brought the highest requirement into an ordinary house project. The requirement reached smaller buildings.
The former exception under which the nearly zero-energy requirement did not apply to houses of up to 220 m² heated area has ended. According to information published by the Ministry of Climate, the five-year transition of houses from low-energy to nearly zero-energy construction was deemed complete from 1 June 2025.
From that date the nearly zero-energy requirements also apply to houses of up to 220 square metres heated area, as covered by the article on houses. A lighter requirement applied to them before.
Summary and four practical rules
A nearly zero-energy building is a technically sound and energy-efficient building built to the best available practice and using renewable energy technologies. The requirement operates on two levels: the lower must be achieved without renewable energy and the higher with it, so solar panels do not compensate for the envelope. Where the roof lacks sufficient sun-facing and unshaded area, the lighter low-energy level applies, and since 1 June 2025 the requirement also covers houses of up to 220 square metres heated area.
Four rules: assess roof orientation and shading early, since the applicable requirement may depend on them. Do not plan renewable energy as a substitute for thermal performance. Take the limit values from the annex to the regulation in force, not from an earlier project. Budget the solar electricity system as part of the requirement, not as an optional extra.
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.