DIY

What Size Generator Do You Need?

Built by Kevin Glover · @gloverbuilds · Verified formula

Calculate the wattage needed for backup power during outages. Home essentials, whole-house, or jobsite.

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

In this article

Sizing Your Generator
Portable vs Standby

Dimensionierung

Laufwatt addieren + größten Anlaufstrom. Kühlschrank: 700W (Anlauf 2.200W). Heizungspumpe: 500W (1.500W). Beleuchtung: 300-600W. Grundversorgung: 3.000-5.000W. In Deutschland: Stromausfälle sind selten (SAIDI ~12 Min/Jahr) aber Vorsorge wächst.

Typen

Inverter (2.000-4.000W): leise, 800-2.500 €. Konventionell (3.000-8.000W): lauter, 500-1.500 €. Stationär mit Umschaltung: 5.000-15.000 €. Für PV-Besitzer: Batteriespeicher (5-15 kWh, 5.000-15.000 €) ist die elegantere Lösung.

⚡ CalcWolf Insight

A whole-house standby generator (Generac, Kohler) installed with an automatic transfer switch is one of the highest-ROI home improvements in areas with frequent outages. It adds $3,000-5,000 to home value and is increasingly expected by buyers in storm-prone and rural areas.

Frequently asked questions

Welche Leistung?▾

Grundversorgung: 3.000-5.000W. Mit Heizung: 5.000-8.000W.

Generator oder Batteriespeicher?▾

Mit PV-Anlage: Batteriespeicher (autark, leise, wartungsfrei). Ohne PV: Generator als Backup.

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Kevin Glover · @gloverbuilds

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 →