Generator Buyer's Guide for Preppers

A generator is the most common power preparedness purchase — and the one with the most significant ongoing fuel dependency. Buying the right generator means understanding what you actually need to power, which fuel makes sense for your situation, and what the critical safety rules are. This guide covers all three.

---

Step 1: Figure Out Your Wattage

Generators are rated in watts. Your devices require watts. Match them.

Running watts vs. starting watts: Devices with motors (refrigerators, pumps, air conditioners) require a surge of power when starting — typically 2–3× their running wattage. A refrigerator that runs at 150W may need 600W to start. Your generator’s peak/surge capacity must exceed this.

Common devices and their power requirements:

Device	Running Watts	Starting Watts
Refrigerator (average)	150W	600W
Chest freezer	60W	200W
Window AC (5,000 BTU)	500W	1,500W
Sump pump (1/2 HP)	800W	2,000W
Well pump (1/2 HP)	800W	2,100W
LED lighting (10 bulbs)	100W	—
CPAP machine	30–50W	—
Phone charging (family)	25W	—
Microwave	1,000W	—
Small electric heater	1,500W	—

For most households: A refrigerator, lights, phone charging, and some small appliances requires 2,000–3,500W. Add a well pump or sump pump and you need 5,000–7,000W.

---

Generator Types

Portable Gas Generator

The most common type. Runs on gasoline, typically outputs 2,000–12,000W, costs $400–$1,500. Simple, widely available, and familiar.

Advantages:

• Wide availability and price range
• High power output for the cost
• Easy to find service

Disadvantages:

• Gasoline degrades in 3–12 months without stabilizer
• Cannot be stored in large quantities safely or legally in most areas
• Loud — typically 65–75 dB at 23 feet
• Requires outdoor operation (carbon monoxide risk)

Inverter Generator

A more sophisticated design that produces cleaner power (safe for sensitive electronics) and runs the engine at variable speed based on load, which significantly improves fuel efficiency and reduces noise.

Advantages:

• Quiet — typically 50–60 dB (roughly conversation level)
• Safe for laptops, phones, CPAP machines, and medical equipment
• Significantly better fuel efficiency at partial load
• Can parallel two identical units for double the output

Disadvantages:

• More expensive per watt than conventional generators
• Lower maximum output (most portable inverter generators cap at 2,000–4,000W)

Dual-Fuel and Tri-Fuel Generators

Dual-fuel generators run on either gasoline or propane (LP). Tri-fuel also adds natural gas capability. This is the most preparedness-relevant configuration.

Why dual-fuel for preparedness:

• Propane stores indefinitely in sealed tanks (unlike gasoline)
• 20-lb propane tanks (standard grill tanks) are widely available
• Propane is cleaner-burning, extends engine life
• Natural gas connection (tri-fuel) provides continuous fuel if your gas service remains active during an outage

Tradeoff: Propane produces about 10–15% less power and runs through fuel slightly faster than gasoline by energy volume.

---

Standby Generator

A permanently installed generator connected to your home’s electrical panel, with an automatic transfer switch that activates within seconds of a power outage. Runs on natural gas or propane from a large tank.

Advantages:

• Automatic — no action required during an outage
• Powers entire home on natural gas (continuous fuel if service is active)
• Quiet, weatherproof installation
• Runs indefinitely on a large propane tank

Disadvantages:

• Expensive: $3,000–$15,000 installed for a whole-home system
• Requires licensed electrician for installation
• Annual maintenance required
• Natural gas may not be available during widespread infrastructure failures

For whole-home preparedness with budget for installation, a 10–20kW standby generator is the most capable solution. For most preppers, a dual-fuel portable is a better value.

---

Fuel Storage

Gasoline:

• Degrades in 3–12 months without fuel stabilizer
• With stabilizer (Sta-Bil): extends to 12–24 months
• Maximum safe home storage depends on local codes — typically 25 gallons in approved containers
• Store in HDPE-approved gasoline cans, away from ignition sources, not in living spaces

Propane:

• Stores indefinitely in sealed tanks — no degradation
• 20-lb tank = ~4.6 gallons = 12–20 hours of generator runtime at moderate load
• 100-lb tank = ~24 gallons = longer runtime; can be exchanged at many gas stations
• Requires proper outdoor storage away from ignition sources

For extended preparedness, propane is the superior storage fuel. Three 20-lb tanks (~$75 at current exchange prices when full) provides 36–60 hours of generator runtime — that’s 3–5 weeks of 2-hours-daily use.

---

The Carbon Monoxide Rule

Carbon monoxide from generators kills people every year, without exception, because it is invisible, odorless, and produces symptoms that can be mistaken for fatigue or the flu.

Absolute rules:

• Never operate a generator indoors — not in a garage, not in an attached structure, not “just for a few minutes”
• Position the generator exhaust away from windows, doors, and vents
• Install carbon monoxide detectors inside the home if a generator is operating outside

The minimum safe distance varies by generator, but most manufacturers specify 20+ feet from any opening. The exhaust direction matters — position the exhaust pointing away from the house, not toward it.

---

Connecting Your Generator Safely

Never backfeed a generator into a wall outlet. This is called “back-feeding” and it is illegal, dangerous to utility workers (it energizes lines they believe are de-energized), and can damage your generator and appliances.

Safe connection options:

• Extension cords: Run heavy-gauge extension cords (12-gauge minimum for most loads) directly from the generator to devices. Simple, safe, no installation required.
• Transfer switch: An electrician installs a manual or automatic transfer switch to your panel. You connect the generator to the transfer switch, which isolates your home from the grid before applying generator power. The safe, permanent solution.
• Interlock kit: A less expensive alternative to a full transfer switch — an interlock prevents the main breaker and generator breaker from being on simultaneously. Requires electrician installation but costs less than a transfer switch.

For occasional outage use with a few appliances, extension cords are adequate. For powering multiple circuits including a well pump or sump pump, a transfer switch is the correct approach.

---

The Recommendation Matrix

Scenario	Recommended Type	Why
Occasional short outages, apartments	Portable inverter (2,000W)	Quiet, portable, safe for electronics
Family home, 1–2 week outages	Dual-fuel portable (3,500–5,000W)	Power + fuel flexibility
Extended outages, well pump, AC	Dual-fuel portable (7,500–10,000W)	Enough wattage for all critical loads
Whole-home backup, automatic	Standby (10–20kW)	Automatic transfer, continuous fuel