Kreditanstalt für Wiederaufbau (KfW; German state-owned investment and development bank)

KfW Programme 261 – "Bundesförderung für effiziente Gebäude – Wohngebäude Kredit" is a low-interest loan programme that supports energy-saving measures and the reduction of CO₂ emissions in residential buildings, implemented on behalf of the Federal Ministry for Economic Affairs. It targets comprehensive whole-building renovations to achieve an Effizienzhaus standard, as well as the purchase of a freshly renovated Effizienzhaus. Unlike KfW 270, which is a straightforward investment loan, Programme 261 combines a subsidised loan with a partial debt forgiveness component: borrowers can receive up to €150,000 per residential unit and a repayment grant (Tilgungszuschuss) of between 5% and 45%, depending on the efficiency level achieved and applicable bonus categories. The higher the energy efficiency of the renovated building — reflected in the Effizienzhaus rating (EH 85, 70, 55, or 40) — the larger the repayment grant awarded.

Eligible applicants include private individuals, homeowners' associations, companies, freelancers, housing cooperatives, and public-law bodies such as chambers and associations. On the technical side, the building must be at least five years old at the time of application, all measures must be carried out by qualified specialist firms, and the applicable technical minimum requirements must be met. Crucially, an independent energy efficiency expert must be engaged before the project begins to develop the overall energy concept and issue the formal "Confirmation for Application" (Bestätigung zum Antrag), which is required for the funding process. Procedurally, the application must be submitted before any construction work begins or delivery and service contracts are signed, and it must be preceded by a documented advisory consultation with a financing partner, recorded on the official KfW form.