Power outages can leave your home without electricity for hours—or days. A portable generator bridges that gap, but only if it's set up correctly. This guide walks you through selecting, installing, and maintaining a portable generator so you're ready when the grid goes down.
Choose the Right Generator Size
Your first decision is wattage. Start by calculating your home's essential loads: refrigerator (600W), furnace (1,000W), well pump (1,500W), water heater (4,500W), and lighting (500W). Add them together to find your minimum need.
Most households running essentials require 5,000–7,500 watts. If you want to power air conditioning or multiple major appliances, plan for 10,000–15,000 watts. Undersized generators will trip their internal breakers; oversized ones waste fuel and money.
Fuel type matters too. Gasoline is cheapest upfront ($400–$800 for 5kW) but burns fast and degrades in storage. Propane lasts longer and stores indefinitely, though propane generators cost 20–30% more. Dual-fuel models offer flexibility but add complexity.
Location and Ventilation Setup
Never run a generator indoors. Carbon monoxide poisoning kills within minutes. Place the unit at least 20 feet from windows, doors, and vents—ideally 30 feet. Point the exhaust away from your home.
For permanent or semi-permanent setups, a weatherproof shed or generator enclosure keeps noise down (generators run 85–95 decibels) and protects equipment from rain. Leave 12 inches of clearance on all sides for air circulation. Concrete pads prevent moisture seepage and provide stable footing.
Fuel Storage and Supply
Gasoline generators need a fuel source. Standard practice is keeping 5–10 gallons in approved, labeled containers in a cool, dry place away from your home. Gasoline degrades after 30 days; add fuel stabilizer to extend shelf life to 6–12 months. Rotate stock seasonally.
If you choose propane, check whether a local supplier can deliver bulk tanks or portable cylinders. Many suppliers offer automatic refill services (similar to heating oil), costing $1,500–$3,000 for a permanent 500-gallon tank installation.
Wiring and Transfer Switch Installation
This is where most people need professional help. A portable generator connects to your home in one of two ways:
- Manual transfer switch: Safer and cheaper ($300–$600). You manually flip a switch to route power from the generator to selected circuits. Requires a licensed electrician.
- Automatic transfer switch (ATS): Detects an outage and switches automatically ($1,500–$3,500 installed). Overkill for most portable setups but eliminates manual intervention.
Never backfeed the main electrical panel directly—it creates electrocution and fire hazards for utility workers. Always use a transfer switch rated for your generator's wattage.
Budget $800–$1,500 total for a licensed electrician to install a manual transfer switch for a 5kW generator. Permit and inspection costs vary by municipality ($50–$200).
Fuel and Maintenance Basics
Change oil every 50–100 hours of operation—typically once per season if used sparingly. Use the oil grade specified in your manual (usually 10W-30).
Run the generator under load monthly for 15 minutes to keep seals fresh and prevent fuel system buildup. Don't just idle it; actually draw 50% of its rated capacity.
Before extended storage (off-season), drain the fuel tank or add stabilizer, change the oil, and store it in a cool, dry place with the choke in the "off" position.
Finding Trusted Installers
Hiring a qualified electrician and generator supplier prevents costly mistakes. Mercoly helps you compare trusted Generators & Backup Power providers in your area, read reviews, and get quotes—all in one place. Check credentials: electricians should be licensed and insured; generators should come with 2–3 year warranties.
Frequently Asked Questions
Q: How long does a portable generator run on a full tank? A: A 5,000W gasoline generator runs 8–12 hours at half load, while propane models run 12–24 hours depending on tank size and load.
Q: Do I need a permit to install a generator? A: Most municipalities require electrical permits and inspections for transfer switch installation; check with your local building department before hiring an electrician.
Q: Can I use a portable generator to power my whole house? A: A portable generator typically powers essentials like refrigeration, heating, and lighting, but not your entire home simultaneously—that's what standby (whole-house) generators do.
Ready to stay powered through the next outage? Start by calculating your wattage needs and getting quotes from licensed installers near you.