Energy-plus house 2026: concept, added cost & funding

A plus-energy house generates more energy over a year than it consumes, usually feeding the surplus into the public grid or charging electric vehicles. This is achieved by combining excellent insulation, a heat pump, a large photovoltaic system, and battery storage. In prefab construction in 2026, it is the most ambitious standard tier offered as a standard product by brands such as SchwörerHaus, Baufritz, and Helma.

GEG legal framework and energy standard

Core technology in 2026: PV, storage, heat pump, ventilation

• 8–14 kWp photovoltaics on south/east and west roofs (typical sizing for a 140 m² detached home).
• 8–12 kWh usable battery storage—increases self-consumption to 60–80%.
• Ground-source or air-to-water heat pump with a high seasonal performance factor (≥ 4.0) for the lowest electricity demand.
• Controlled residential ventilation with heat recovery (η ≥ 85%).
• U-values well below the GEG reference: external wall 0.12–0.15 W/(m²K), windows Uw ≤ 0.90.
• Smart meter and energy-management system for load shifting (heat pump + wallbox).

Funding in 2026: KfW, EEG, and self-consumption

Plus-energy houses qualify for reduced-interest financing through KfW Climate-Friendly New Construction funding (KFN 297/298)—up to €150,000 in credit per residential unit with QNG certification. Since 2023, the zero VAT rate has also applied to purchasing and installing the PV system; remaining electricity fed into the grid is paid at the EEG tariff. Overall, the additional cost over an EH 55 standard house pays back in 12 to 18 years in 2026, and considerably faster if electricity prices rise.