ENERGY
KfW heating-subsidy conditions changed on 21 July 2026
Programme 458 has revised eligible-cost caps and bonus rules; the efficiency bonus and emissions supplement were removed.
RATIOXA ENERGY
Calculate solar, heat pumps & energy cost
Evaluate investments through real cash flows, NPV, IRR and robust break-even points.
CURRENT CONTEXT
What changed?
Curated developments that may affect a RATIOXA assumption. Every update requires a visible source.
Available
What do you want to figure out?
A system for decisions that deserve more than a gut feeling.
01Open →02Open →03Open →04Open →
Energy · DECISION TOOL
Does solar pay?
Self-consumption, export, NPV, IRR and payback.
NPV · PaybackEnergy · DECISION TOOL
Heat pump or gas?
Present-value comparison of investment, efficiency and energy.
Present-value cost · SCOP crossoverEnergy · DECISION TOOL
Battery storage
Cycles, efficiency, degradation and net present value.
NPV · PaybackEnergy · QUICK TOOL
Energy cost
Project consumption, tariff and price changes.
Total cost · Monthly averageRATIOXA METHOD
Not just: What costs less?
What changes the answer?
Crossovers are found with robust numerical solvers inside defined bounds.
How we calculate →