Home Generator: Complete Buying and Operating Guide

Types of Home Generators

Conventional Generators

Gasoline generators (1,000-10,000W): Most common, widely available, moderate cost. Runs on standard gasoline. Disadvantage: produce significant noise (65-75 dB), require separate storage of flammable fuel, higher fuel consumption.

Diesel generators: More fuel-efficient, longer-running. Diesel is more stable in storage than gasoline. Better for longer outages. Higher initial cost.

Propane/gas generators: Very quiet, burns cleaner, propane stores indefinitely. Requires propane tank installation or gas connection. Good for extended backup power.

Inverter Generators

Inverter generators produce "clean" sine-wave power, making them safe for sensitive electronics (laptops, medical devices). Also much quieter than conventional generators (50-60 dB vs. 65-75 dB). Higher cost but strongly recommended for home use.

Best choice for most homeowners: a 2,000-3,000W inverter generator.

Correct Sizing

Step 1: List your critical loads

Device	Running Watts	Starting Watts
Refrigerator	100-200W	600-800W
Chest freezer	80-150W	400-600W
Sump pump	750-1,000W	1,500-2,000W
LED lighting (10 bulbs)	100W	100W
Phone/laptop charging	100-200W	100-200W

Step 2: Calculate total starting watts

Starting (surge) watts determine the minimum generator size. The device with the highest starting watts usually sets the minimum. Add the running watts of everything else you want to run simultaneously.

Example: Refrigerator (800W start) + freezer (600W start) + lights + charging = need 3,000W generator minimum.

Rule of thumb: Size 20-30% above your calculated needs for comfortable headroom.

Legal Requirements in Germany

Noise regulations: Most residential zones prohibit generators from 10 PM to 7 AM. Emergency exceptions apply (actual emergency) but routine testing should be done during permitted hours.

Grid connection: You cannot connect a generator directly to house wiring without a transfer switch. This prevents backfeed into the grid, which can kill utility workers. A licensed electrician must install an interlock or transfer switch.

Indoor use: Strictly prohibited. Carbon monoxide poisoning from indoor generator use kills dozens per year in Europe. Generators must be outdoors with exhaust away from any opening.

Safe Operation

Before starting

Check oil level (most small generators will seize without oil)
Check fuel level
Position outdoors, exhaust pointing away from buildings
Keep 3+ meters from windows and doors

During operation

Never refuel while running (fire hazard)
Monitor weather — generators must not get wet
Keep children and pets away from generator
Test monthly to ensure starting reliability

Fuel storage

Maximum storage: 10-20 liters in approved containers
Fuel additive (STA-BIL) extends gasoline shelf life from 3-6 months to 12-24 months
Store away from living areas and heat sources

What a Generator Doesn't Do

Replace a full electrical system: You'll need extension cords to individual devices, or a transfer switch for selected circuits
Run silently: Even quiet inverter generators are audible outside
Self-start during a power outage: Standard generators require manual start (battery-start models available but at premium cost)

A generator is a practical tool for temporary outages. It's not a set-and-forget system. Understand its limitations before depending on it.

Recommended Approach for Most Households

Small outages (1-3 days): Portable power station (400-1,000Wh) + solar panels is quieter, simpler, safer
Longer outages with high load needs: 2,000-3,000W inverter generator + fuel storage
Extended or whole-house backup: Standby generator with automatic transfer switch (professional installation required)