QNG Profitability Calculator

Compare EH55 baseline vs. EH40 and EH40+PV scenarios.

Parameters
Scenario 1: EH55 (Baseline)
€
%
Scenario 2: EH40
€
%
€
Scenario 3: EH40+PV (QNG)
€
%
€
%
kWh
€
€
Scenario 1: EH55

Baseline for comparison

Loan:
Rate:
Scenario 2: EH40
Interest Saved (10y):
Energy Saved (10y):
Break-Even Year:
10y Net Benefit:
Scenario 3: EH40+PV
Interest Saved (10y):
Energy+PV Saved (10y):
Break-Even Year:
10y Net Benefit:

Ready to Calculate

Adjust the parameters to see the side-by-side analysis.

Frequently Asked Questions

EH55 and EH40 refer to the Efficiency House standards in Germany. EH55 means the building uses only 55% of the primary energy of a reference building, while EH40 uses only 40%. Lower numbers indicate higher energy efficiency.

The QNG (Qualitätssiegel Nachhaltiges Gebäude) is a German state seal of quality for sustainable buildings. It is required to unlock the highest KfW subsidy levels (up to 150,000 € subsidized loan).

The calculator compares the total financial outflow (interest payments + upgrade costs) of EH40 and EH40+PV scenarios against the EH55 baseline. It factors in interest savings from subsidies and reduced energy costs over 25 years.

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Detailed Methodology & Calculation Logic

Financing Logic

The calculator compares different mortgage setups with varying loan amounts and interest rates (reflecting KfW subsidies).

  • Interest Differential: Calculates the total interest paid for each scenario over a 10-year period.
  • Baseline Comparison: All benefits are calculated relative to the EH55 baseline scenario.
Profitability & ROI

We perform a 25-year lifecycle analysis to identify when higher energy standards pay off.

  • Energy Savings: Includes annual savings from reduced thermal demand and PV yield.
  • Net Profit: Calculated as (Interest Saved + Energy Yield) - Upfront Upgrade Costs relative to EH55.
Last updated: 2026-03-26