What Size Generator to Run My Whole House?

Quick Answer: For a typical whole house, you will likely need a generator in the 15,000 to 30,000-watt range. The exact size depends on the home's square footage and number of appliances. A 15,000-watt unit can cover essentials in a 2,000-square-foot house. Go with a 22,000-30,000 watt generator for a larger 3,000+ square foot home to power AC units, heaters, well pumps and more. Carefully calculate your total home wattage needs, and size the generator to at least double that for safe, reliable backup power. Choosing the right sized whole house generator ensures you can maintain normal living comforts, even during extended outages.


Having a whole-house generator allows homeowners to maintain normal living standards even during extended power outages. Choosing the properly sized unit is crucial to ensure all electrical systems and appliances function when utility power fails. The generator must be large enough to handle the home's total wattage needs while factoring in square footage and future energy demands. This article explains how to calculate your household's electrical requirements and select an adequately powered generator for complete backup capability.

Calculate Your Power Needs

The most important factor in selecting a whole-house generator is calculating your home's power needs. Add up the wattage of all electrical appliances and devices you'd like to run during an outage. This includes lighting, appliances like refrigerators and freezers, furnaces, security systems, well pumps, and other necessities. As a general guideline, sizing your generator at twice your total wattage needs will provide enough power. It's also smart to factor in future energy needs if you plan to purchase additional appliances. A professionally installed home generator will safely and automatically power appliances and systems during an outage.

VTOMAN flashspeed 1500 runs all electronic devices during an outage

Size the Generator Based on Home Size

Once you've calculated your power requirements, you can determine the appropriate generator size. Most whole-house generator systems range from 10,000 watts to 60,000 watts. Here are some typical wattage guidelines based on home square footage:

  • Under 2,000 square feet: A 10,000 to 15,000-watt generator can cover essentials like lights, fridges, freezers, furnaces and medical devices. This site is best suited for smaller cottages and cabins.
  • 2,000 to 3,000 square feet: Go with a 15,000 to 22,000-watt unit for a moderately sized home. This will allow you to run most appliances, A/C units, sump pumps and other common home systems.
  • 3,000 to 5,000 square feet: For larger homes, choose a 22,000 to 32,000-watt generator. This range can handle electric ovens, hot water heaters, multiple HVAC units and other major appliances.
  • Over 5,000 square feet: Homes over 5,000 square feet often require 36,000 watts or more, especially if you have amenities like a swimming pool, hot tub, or electric vehicle charging. Large custom homes may need 50,000+ watts.

The larger your home's square footage, the more electrical load you'll be drawing. Carefully match the generator's wattage output to your home's size and systems for proper coverage during outages. An adequately sized unit will automatically power your most important appliances.

Can a Portable Solar Generator Power a Whole House?

Well, most portable solar generators lack the power capacity to fully power a complete house. The power output of most mainstream portable solar generators ranges from 100 to 3000 watts. This level of power can run smaller home appliances like phones, laptops, and lighting. However, it's not enough to handle high-draw appliances like air conditioners, water heaters, and electric stoves.

A full-sized home, especially in extreme climates, requires heating in winter and air conditioning in summer. These systems draw over 3000 watts. So, typical portable solar generators struggle to meet the electrical demands of a whole house.

When to Choose Whole House Generators vs. Portable Solar Generators?

Whole house generators offer complete electrical backup, automatically powering HVAC systems, well pumps, major appliances and your home's entire wiring. Portable solar generators provide only limited power for small devices and lights. When choosing between them, consider your electrical needs and budget:

  • If you require full home backup power to maintain normal living standards during multi-day outages, a permanently installed whole-house generator running on natural gas or diesel is the best option.
  • If you just need to charge devices and run a few small appliances during shorter outages, a portable solar generator can suffice. They're much cheaper upfront but have minimal power capacity.
  • Homeowners who want both solar power and full home backup can install a large solar and battery storage system tied to a whole-house generator as the backup source. This is a robust but more expensive solution.
  • Renters and anyone needing a more budget-friendly option should choose a gas-powered portable generator sized for essential devices and some small appliances.

So weigh your needs, budget and how much backup power you require when deciding between whole-house generators versus more limited portable solar generators.

Factors to consider when choosing a whole house generator vs. a portable solar generator


Reliable backup electricity brings peace of mind when dangerous storms knock out utility power. Carefully calculating your home's total wattage needs and generator sizing guidelines will ensure you choose a system capable of powering essential and everyday appliances. Though whole house units require a bigger investment, their automatic operation and full home coverage provide true energy security. With the right generator sized to your electrical loads and living space, your home will stay powered on even through prolonged outages.

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