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What Size Generator Do I Need? Generator Sizing Guide
Generator Sizing Guide for Homes
Choosing the correct generator size is one of the most important steps when preparing for power outages, off-grid living, or emergency backup power. A generator that is too small may overload and shut down, while an oversized generator can cost more than necessary to purchase and operate.
This generator sizing guide explains how to determine the correct generator size for your home, appliances, and backup power needs. Whether you are looking for a portable generator, diesel generator, or solar generator, understanding wattage requirements will help you choose the right power system.
AllProGenerators offers a wide selection of reliable generator solutions, including diesel generators, solar generators, and portable generators designed for residential, commercial, and off-grid power applications.
Quick Generator Size Calculator
Use this general rule to estimate generator size based on how much power your home requires:
- Essential appliances only: 5,000 – 7,500 watts
- Small home backup: 8,000 – 12,000 watts
- Average home backup: 12,000 – 20,000 watts
- Large homes or full backup: 20,000 – 30,000+ watts
Heavy-duty standby generators such as the Cummins 30kW Diesel Generator or rugged industrial models like the Yanmar Diesel Generator are commonly used for whole-home backup power systems.
Generator Size by House Size
| Home Size | Recommended Generator Size | Typical Usage |
|---|---|---|
| 1,000 – 1,500 sq ft | 7kW – 10kW | Essential appliances and lighting |
| 1,500 – 2,500 sq ft | 12kW – 18kW | Most home backup needs |
| 2,500 – 4,000 sq ft | 18kW – 26kW | Central AC and multiple appliances |
| 4,000+ sq ft | 26kW – 40kW+ | Large homes and estates |
Common Appliance Wattage Chart
To determine the correct generator size, add up the wattage of the appliances you want to power during an outage.
| Appliance | Running Watts |
|---|---|
| Refrigerator | 600 watts |
| Microwave | 1200 watts |
| Window AC | 1000 – 1500 watts |
| Central AC | 3000 – 5000 watts |
| Well Pump | 1000 watts |
| Electric Water Heater | 4000 watts |
| Lights & electronics | 300 – 1000 watts |
Portable Generator vs Diesel Generator
Portable Generators
Portable generators are ideal for temporary power during storms, job sites, RV travel, or emergency outages. They are affordable, flexible, and easy to move.
Browse available models here:
Diesel Generators
Diesel generators are known for long engine life, excellent fuel efficiency, and durability during extended power outages. Many industrial and residential backup systems rely on diesel engines because of their reliability.
Browse diesel generator options:
Solar Generators
Solar generators provide clean, quiet backup power using rechargeable batteries and solar panels. They are ideal for off-grid living, RV travel, and emergency preparedness.
View solar generator systems:
Frequently Asked Questions
What size generator do I need to run a house?
Most homes require between 12kW and 20kW for full backup power. Smaller generators around 5kW to 7kW can power essential appliances such as refrigerators, lights, and electronics.
Will a 10kW generator run a house?
A 10kW generator can run essential circuits including refrigerators, lighting, sump pumps, and smaller HVAC systems.
Is a diesel generator better for backup power?
Diesel generators are widely used for backup power because they provide long engine life, fuel efficiency, and reliability during extended outages.
What size generator runs central air?
Central air conditioning systems usually require between 3,000 and 5,000 running watts with higher startup wattage. Most homes with central AC benefit from generators in the 15kW to 25kW range.
Find the Right Generator for Your Power Needs
Choosing the right generator ensures dependable power during outages, off-grid living, and emergencies. AllProGenerators offers a wide range of reliable power solutions, including diesel generators, solar generators, and portable power stations.
Explore available generator collections below:
Call us anytime with any questions! 954-249-2314
