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The Qualitätssiegel Nachhaltiges Gebäude is a state-quality seal for buildings. The prerequisite for the award of the quality seal is proof of the fulfillment of general and special requirements for the ecological, socio-cultural and economic quality of buildings.
The quality seal is awarded by independent bodies on behalf of the Federal Ministry of Construction after certification. The quality seal is awarded in the requirement level 'PLUS' or 'PREMIUM'. These quality seal levels carry specific set benchmarks for residential buildings:
QNG-PLUS is awarded in cases where CO2e/(m2*year) is no higher than 24kg CO2e/(m2*year) and the calculated non-renewable primary energy requirement of the building is no higher than 96 kWh/(m2*year).
QNG-PREMIUM is awarded in cases where the CO2e/(m2*year) is no higher than 20kg CO2e/(m2*year) and the non-renewable primary energy requirement of the building is no higher than 64 kWh/(m2*year).
For non-residential buildings, the benchmarks are determined on a project-specific basis, as detailed in Annex 3 of the QNG manual.
The included building elements include, among other things, the building parts from Kostgruppen (KG) 300 according to DIN 276 (2018) as well as defined building systems of KG 400. Outdoor components according to KG 500 are to be taken into account if they are absolutely necessary to maintain building operations.
All building materials with a share of more than 1% of the total mass of the building, more than 1% of the primary energy consumption (non-renewable) or more than 1% of GWP100 must be taken into account.
The sum of the neglected building materials must not exceed 5% of the mass of the building, the primary energy consumption (non-renewable) or GWP100.
Small parts processed on-site or in a factory (e.g. nails, dowels, screws) and product-specific small quantities (≤ 1kg) may be neglected.
Create a Project
Create a building project and select the ' LCA for Qualitätssiegel Nachhaltiges Gebäude (QNG)' tool as the chosen calculation tool.
Create Your First design and Select LCA Parameters
Ensure that the 'Product specific service life' is selected for the default service life value.
Mandatory Scope
The scope can be found above or in the guidance directly.
Calculation Period
Set the calculation period to 50 years by opening the ‘Calculation Period’ tab and inputting 50 years.
Building Area
Fill in the Building area question form by entering the appropriate area in 'Netto-Raumfläche, NRF'.
Building Materials
Fill in your project information in One Click LCA by entering the design either manually or by importing your data (see different import options here; guidance for data import can be found here). If you need help finding the right datasets for your building materials, check our guidance pages here and here.
Only generic QNG data ("Rechenwerte") is available in this tool. The tool also includes base amounts ("Sockelbeträge") for building technology under the 'HVAC components and equipment' material category which users should select based on the requirement level ('PLUS' or 'PREMIUM'), the building's energy performance and the building's type (defined by classes K1 to K6 which can be found in the QNG guidance). These should be used in conjunction with the building technology equipment that will actually be installed.
Energy consumption
Input energy as required by the calculation scope for one year. This value will be multiplied by the calculation period for full-lifecycle results.
In the QNG calculation, energy is divided into three subclasses:
B6.1: This is regulated energy consumption (required for all building types, input in kWh).
The total B6.1 values for consumed energy are calculated using the GEG model. This includes the loads from heating, cooling, ventilation, dehumidification and humidification of the building according to the planned fabric condition of the envelope, the planned building services and the planned zonal conditioning.
For heat, the data set for the specific energy source is used, and for electricity, the data point “Usage - 1 kWh national grid electricity mix, version 1.2” must be used.
B6.2: This is the unregulated energy consumption for the operation of the building. It is excluded from residential buildings. It includes elevators and central services (low voltage systems & video surveillance). The corresponding resources can be found in section 1 of the energy consumption tab.
Elevators: Use Tables 11 and 12 in the QNG guides to determine which resources to use for the elevators you have.
Low-voltage systems: Low-voltage systems are reported per NRF. You will need to enter an additional low-current asset resource for each low-voltage system used.
Video surveillance: CCTV is reported per surveillance area
B6.3: This is a default value for the energy consumption of users, taken from default values in kWh/(m2*year). For non-residential buildings values are defined per usage type (input per m2 of usage type) and for residential buildings, there is a lump sum of 20 kWh/(m2*year).
PV impact: As per the QNG rules, the electricity requirement should initially be covered by the self-used portion of the energy produced on site, while the remainder is drawn from the grid. The self-used energy is with a primary energy and emission factor of zero. To represent the effect of this renewable energy use in the tool, add the kWh produced as a negative value and assign it to the classification "Eigengenutzter Anteil erneuerbarer Energie" in the cost group column.
Exported energy: As per QNG rules, you need to account for exported energy, which is reported in module D2. Input your kWh values in section 4, “Exported energy”. Enter them as positive kWh values – the calculation automatically converts them to negatives to represent benefits in module D2.
General note: The datapoints should be added as separate inputs and then marked appropriately using the cost group options to refer to the respective B6 subclass.
Reference Values
As mentioned in the beginning of this article, there are fixed benchmark values for residential buildings. To represent this in the software, select the resource “Reference value for DGNB 2023/QNG, Residential building” in section 1 of the reference values tab.
For non-residential buildings, the reference building's performance is based on various parts:
Construction-related part:
For the aspect that concerns A1-A3, B4, C3-C4 of cost groups 300 and 400, input the NRF for the resource that matches the LCA class of your building. This can be found in section 1 of the ‘Reference values’ tab.
To represent the top-up factor for A1-A3, B4, and C3-C4 of PV systems, the respective resources for roof area may be used. There are many with different self-usage shares. The QNG mentions 40% for the ones without battery storage (page 14) and in the case of determining the pro rata requirement value (page 11).
Energy-related part:
B6.1: For B6.1, the QNG rules for the determination of the reference value for non-residential buildings refer to the GEG ANNEX 2 and provide further requirements on calculating the kWh.
The resource 'Utilization - 1 kWh national grid electricity mix - QNG', which can be found in section 2, is used to input the electricity usage for this category (in kWh).
As per QNG rules, the heating is represented through natural gas.
Please note that the kWh values to be entered for B6.1 must first be reduced by the corresponding reduction factor (see Table 11 in QNG rules).
B6.2: Resources for central services and elevators can be found in section 2 of the 'Reference values' tab. For more information on how to input this see part about B6.2 in the energy consumption section.
B6.3: For representing B6.3, you can find the resources for usage for various zones in section 2 and input them per NRF.
PV impact: Finally, you need to subtract the energy generated on site that can replace grid electricity. In the software, this is done by converting kWpeak to kWh: Assuming a self-use share of 40%, the solar energy generated by the reference building PV system is calculated as kWpeak*0.4*1000. The KWpeak is calculated with Formula 1 in the QNG guidance. The resulting kWh is input as a negative value to reduce the total B6 and assigned to the class "Eigengenutzter Anteil erneuerbarer Energie” in the cost group column. The resource used for this is “Utilization - 1 kWh national grid electricity mix, version 1.2”.
Exported energy: No reference values are to be determined for module D2 (and D1, see the QNG rules for the determination of the reference value for non-residential buildings, page 9).
General note: The datapoints should be added as separate inputs and then marked appropriately using the available options in the cost group column to refer to the respective B6 subclass. Otherwise, one risks that no values will show in the results table for these subclasses.
Results
The results summary table is used to report the impacts as per the QNG guidance (see page 20 for residential guidance and page 26 for non-residential building guidance).
The rows concerning the Fulfillment of QNG-PLUS and QNG-PREMIUM show 1 if they are achieved, and 0 if they aren't.