How much does a whole house generator cost?

Unit only: $3,000-$15,000. Installation: $3,000-$10,000. Total installed: $6,000-$25,000. By size: essential circuits (7.5 kW): $6,000-$10,000. Most of home (14-20 kW): $10,000-$18,000. Whole home + AC (22-48 kW): $15,000-$25,000+. Fuel connection: natural gas (if available) or propane tank. Annual maintenance: $200-$500. Permits: required in most areas ($100-$500). Get 3+ quotes from authorized dealers/installers.

What size generator do I need?

For essential circuits (fridge, lights, furnace, sump pump): 5,000-7,500 watts. For most of home: 10,000-16,000 watts. For whole home including central AC: 20,000-48,000 watts. How to calculate: list appliances you want to power. Add running wattage. Account for starting wattage (motors need 2-3x to start). Add 20% margin. Quick rule: home square footage x 5 = approximate watts needed for whole-home backup (very rough estimate).

Portable vs standby generator - which should I get?

Portable: $300-$3,000. Manual start. Must run outdoors. 1,000-12,000W. Gasoline (needs refueling). Best for: occasional short outages, budget-conscious, renters. Standby: $6,000-$25,000 installed. Automatic (turns on in seconds). Permanent outdoor installation. 7,500-48,000W. Natural gas or propane (no refueling). Best for: frequent or long outages, medical equipment, home business, convenience. Middle ground: portable generator + manual transfer switch ($300-$800 installed) lets you safely power specific circuits without a standby generator.

How often should I maintain my generator?

Portable generator: change oil every 50-100 hours of use. Replace spark plug annually. Drain fuel if storing more than 30 days (or use fuel stabilizer). Run it for 30 minutes monthly to keep it ready. Standby generator: weekly automatic exercise cycle (built into most units, runs 10-20 minutes). Annual professional maintenance: $200-$500 (oil change, filter, spark plugs, battery check, load test). Replace battery every 3 years. Change oil and filters annually. Inspect coolant (liquid-cooled models) annually.

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Woodworking & Lumber

Generator Guide: Types, Cost & Sizing for Your Home

Lumberama Editorial Team, Emergency Power & Home Improvement Specialists Nov 13, 2026 9 min read

Generator Types

Portable generator: Power output: 1,000-12,000 watts. Fuel: gasoline (most common), dual fuel (gas + propane). Cost: $300-$3,000. Pros: affordable, versatile, no installation needed. Cons: must be started manually, runs outdoors only (CO risk), limited power, loud, requires refueling. Best for: occasional power outages, camping, job sites.

Inverter generator: Power output: 1,000-7,500 watts. Fuel: gasoline or dual fuel. Cost: $400-$4,000. Pros: quiet, clean power (safe for electronics), fuel efficient, lightweight. Cons: lower power output, more expensive per watt. Best for: sensitive electronics, RV use, smaller backup needs.

Standby (whole-house) generator: Power output: 7,500-48,000+ watts. Fuel: natural gas or propane (connected to existing supply). Cost: $3,000-$15,000 (unit) + $3,000-$10,000 (installation). Pros: automatic (turns on within seconds of outage), powers entire home, runs on utility gas (no refueling), quiet. Cons: expensive, permanent installation, requires maintenance. Best for: frequent or long outages, medical equipment needs, home-based business, whole-home backup.

Cost

Portable generator: Small (2,000-3,500W): $300-$800. Medium (5,000-7,500W): $600-$1,500. Large (10,000-12,000W): $1,000-$3,000. Transfer switch (recommended): $300-$800 installed.

Standby generator: Unit only: $3,000-$15,000. Installation: $3,000-$10,000. Total installed: $6,000-$25,000. By size: 7.5 kW (essential circuits): $6,000-$10,000. 14-20 kW (most of home): $10,000-$18,000. 22-48 kW (entire home + AC): $15,000-$25,000+. Popular brands: Generac (most popular residential), Kohler, Briggs & Stratton, Champion, Cummins.

Sizing

How to size a generator: List everything you want to power during an outage. Add up the running watts. Account for starting watts (motors need 2-3x running watts to start). Add 20% safety margin.

Common appliance wattages: Refrigerator: 400-800W (running), 1,200-2,400W (starting). Furnace fan: 500-700W (running), 1,000-2,100W (starting). Sump pump: 800-1,000W (running), 1,500-2,500W (starting). Window AC: 500-1,500W. Central AC: 3,000-6,000W. Well pump: 1,000-2,000W (running), 2,000-4,000W (starting). Lights: 60-600W total. TV/computer: 100-400W. Microwave: 1,000-1,800W.

Typical sizing: Essential circuits only (fridge, lights, furnace, sump pump): 5,000-7,500W. Most of home (add kitchen, laundry): 10,000-16,000W. Whole home including central AC: 20,000-48,000W.