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CalcWolf DIY Warmwasserspeicher-Rechner
DIY

What Size Water Heater Do You Need?

Calculate the right water heater capacity for your household. Tank size by family size, usage patterns, and climate.

📅 Updated April 2026 Formula verified 📖 4 min read 🆓 Free · No sign-up

Dimensionierung

1-2 Personen: 80-120 Liter. 3-4: 150-200 L. 5+: 200-300 L. In Deutschland dominiert die Zentralheizung mit Warmwasserspeicher. Durchlauferhitzer: beliebt in Altbauten ohne Zentralwarmwasser (21-27 kW elektrisch). Die Wärmepumpe (Brauchwasser-WP): 1.500-3.000 € — spart 50-70% Warmwasserkosten.

Alternativen

Solarthermie: 3.000-6.000 € installiert, deckt 50-60% des Warmwasserbedarfs. In Deutschland mit BAFA-Förderung. Durchlauferhitzer: keine Speicherverluste, sofort warmes Wasser, aber hoher Stromverbrauch bei elektrisch.

⚡ CalcWolf Insight

The heat pump water heater is the biggest energy savings opportunity in most homes. It uses 50-65% less electricity than a standard electric tank by extracting heat from surrounding air. The $300 federal tax credit and many state/utility rebates can reduce the price premium to near zero.

Frequently asked questions
Welche Größe für 4 Personen?
Speicher: 150-200 L. Durchlauferhitzer: 21-24 kW (Dusche + Waschbecken gleichzeitig).
Solarthermie oder Wärmepumpe?
Solarthermie: 50-60% Deckung, wetterabhängig. Brauchwasser-WP: 50-70% Ersparnis, wetterunabhängig. WP ist effizienter.
✓ Math logic verified against primary sources → See our verification process
Kevin Glover
Founder, CalcWolf · GLVTS · Blickr
All formulas sourced from primary references — IRS publications, peer-reviewed research, and official standards. Results are tested against independent reference calculators before publishing. Rates and brackets updated when official sources change. Editorial policy →
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