Energy-efficient house in the NF-40 and NF-15 standard – what does it mean?

At present, in order to obtain a building permit, each new building project must meet clearly defined energy efficiency guidelines. The assumption applicable in the European Union can be found in the document Directive 2010/31/EU. In turn, EU directives become the basis for a number of changes in legal acts applicable in Poland.

An example may be the Regulation of the Minister of Infrastructure on the technical conditions that should be met by buildings and their location – in Section X there, a gradual tightening of the requirements for the EP indicator, which is the essence of the Energy Performance of a building, was introduced, and Annex No. 2 to the aforementioned regulation specifies the U indicator for building partitions.

New construction projects submitted after 31.12.2020 should comply with the requirements for technical conditions (currently WT2021). In their case, the insulation indices of partitions are:
– for internal walls: maximum 0.20 W (m2*K)
– for roofs: maximum 0.15 W (m2*K)
– for floors on the ground: maximum 0.30 W (m2*K).

Energy-saving passive and zero-energy buildings

The better the insulated building, the more energy-efficient it is – it is therefore worth striving for the lowest possible heat losses, which are minimized, for example, by the materials used to produce building partitions.

A zero-energy house is self-sufficient – it is characterized by zero net energy consumption and zero carbon dioxide emissions throughout the year. Passive houses, on the other hand, are characterized by very low heating energy demand – below 15 kWh/(m²/year). They lack traditional heating installations and devices. Instead, passive and internal heat sources are used to heat radiators and utility water: photovoltaics and heat pumps, recuperation, profits from residents, reheating devices, etc. In addition, thermal bridges are also eliminated, windows with three-chamber glass with a high coefficient are used, and the building is tight.

NF-40 and NF-15 standards

Just a few years ago, when a house design met the requirements specified as NF-40 and NF-15, the investor could receive a subsidy from the state budget for their construction. These standards were introduced by the National Fund for Environmental Protection and Water Management and were the upper threshold on which the subsidy for the loan would be obtained. This program has now been completed, while buildings constructed in accordance with the guidelines contained therein were characterized by the parameters described below.

NF-40 Standard – Requirements

In this standard, the heat transfer coefficient is:

– for internal walls: maximum 0.15 W (m2K) for climate zones I, II and III of Poland and maximum 0.12 W (m2K) for climate zones IV and V
– for roofs: maximum 0.12 W (m2K) for climate zones I, II and III and maximum 0.10 W (m2K) for climate zones IV and V
– for floors on the ground: maximum 0.20 W (m2K) for climate zones I, II and III and maximum 0.15 W (m2K) for climate zones IV and V.

NF-15 Standard – Requirements

In this standard, the heat transfer coefficient is:

– for internal walls: maximum 0.10 W (m2K) for climate zones I, II and III and maximum 0.08 W (m2K) for climate zones IV and V
– for roofs: maximum 0.10 W (m2K) for climate zones I, II and III and maximum 0.08 W (m2K) for climate zones IV and V
– for floors on the ground: maximum 0.12 W (m2K) for climate zones I, II and III and maximum 0.10 W (m2K) for climate zones IV and V.

The EP heat index determines the annual demand for primary energy of a building, necessary for everyday functioning – we are talking not only about heating the house, but also about utility water, as well as cooling, lighting and ventilation. In the case of Mabudo house designs, this value (indicated in the Energy Characteristics) is well below the upper limit required in each of the previously mentioned standards.

This is mainly due to the selected method of heating the building. At Mabudo, we encourage you to focus on renewable energy sources, such as a combination of photovoltaic panels with an efficient heat pump. Both of these investments can be obtained with favorable subsidies from various subsidy programs – both national and regional. Examples include the Green House and Green Mortgage programs. The Green House Certificate is awarded to buildings by the Polish Ecological Building Society, and for the purchase of such properties you can get a subsidy to the loan from partner banks.

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