Generator Buying Guide: 10 Best Tips for the Ultimate Purchase Decision

In an increasingly interconnected world, reliable power is not just a convenience; it’s a necessity. Whether you’re preparing for unexpected outages, seeking a portable power source for outdoor adventures, or requiring consistent energy for a job site, a generator offers peace of mind and operational continuity. However, navigating the vast array of options can be daunting. This essential generator buying guide is designed to demystify the process, helping you understand the key considerations and choose the perfect generator to meet your specific power needs.

A generator is a significant investment, and making an informed decision ensures you get the most value, efficiency, and reliability for your money. We’ll explore the various types of generators, delve into how to accurately calculate your power requirements, discuss essential features, and highlight important safety considerations. By the end of this guide, you’ll be equipped with the knowledge to select a generator that provides dependable power when you need it most.

Understanding the Different Types of Generators

The first step in your generator buying journey is understanding the fundamental differences between the main types available. Each type is designed for specific applications and offers distinct advantages and disadvantages.

Standby Generators (Whole-House Generators)

Standby generators are permanent installations, typically powered by natural gas or liquid propane, and are designed to automatically turn on within seconds of a power outage. They are connected directly to your home’s electrical system via an automatic transfer switch (ATS), which senses an outage and seamlessly switches your power source. When utility power is restored, the ATS switches back, and the generator shuts down.

Pros: Fully automatic operation, can power an entire home or critical circuits, quieter than portable models, runs on readily available fuels (natural gas, LP), increases home value.
Cons: High initial cost (unit plus installation), requires professional installation, regular maintenance contracts are often recommended.
Best for: Homeowners in areas prone to frequent outages, those who need to power critical medical equipment, or anyone seeking complete whole-house power protection without manual intervention.

Portable Generators

Portable generators are versatile and mobile, offering power when and where you need it. They are typically fueled by gasoline or propane and come in various sizes, from small recreational models to larger units capable of powering several essential home appliances. They require manual starting and must be connected to appliances via extension cords or to a home’s electrical system via a manual transfer switch and a specific inlet box (never plug directly into a wall outlet).

Pros: More affordable than standby generators, highly portable, can be used for camping, tailgating, job sites, and emergency home backup.
Cons: Require manual operation, can be noisy, produce exhaust fumes (must be used outdoors), fuel storage can be an issue, generally less powerful than standby units.
Best for: Recreational use, occasional home backup for essential circuits, job sites, and situations where mobility is key.

Inverter Generators

Inverter generators are a subset of portable generators known for their advanced technology. They produce AC power, convert it to DC, and then invert it back to clean AC power. This multi-step process results in a stable, high-quality power output (often referred to as ‘clean power’) that is safe for sensitive electronics like laptops, smartphones, and medical devices. They are also typically much quieter and more fuel-efficient than traditional portable generators.

Pros: Quiet operation, excellent fuel efficiency, clean power output (safe for sensitive electronics), lightweight and compact for easy transport.
Cons: Generally more expensive than conventional portable generators of similar wattage, less powerful than larger conventional portable or standby units.
Best for: Camping, RVs, tailgating, powering sensitive electronics, and situations where noise levels are a concern.

Dual Fuel and Tri-Fuel Generators

These generators offer the flexibility of running on more than one type of fuel. Dual-fuel generators typically run on gasoline and propane, while tri-fuel models can also incorporate natural gas. This versatility can be a significant advantage, especially during extended power outages when one fuel type might be scarce.

Pros: Fuel flexibility provides options during emergencies, propane has a longer shelf life than gasoline, natural gas offers a continuous fuel supply if available.
Cons: Can be more expensive than single-fuel models, performance might vary slightly between fuel types.
Best for: Users who want fuel redundancy, those with access to natural gas lines, or individuals who prefer the storage benefits of propane.

Calculating Your Power Needs (Wattage Requirements)

This is arguably the most critical step in your generator buying guide. Buying a generator that’s too small will leave you without power for essential items, while one that’s too large might be an unnecessary expense and less fuel-efficient. You need to determine both the starting wattage and running wattage for the appliances you intend to power.

Understanding Starting Wattage vs. Running Wattage

Running Wattage (Rated/Continuous Wattage): This is the power an appliance continuously draws to operate.
Starting Wattage (Surge/Peak Wattage): Many appliances, especially those with induction motors (refrigerators, air conditioners, well pumps), require a momentary burst of extra power to start up. This surge can be 2-3 times their running wattage.

Step-by-Step Calculation

List All Essential Appliances: Go through your home or consider your specific application (e.g., camping) and list every appliance you absolutely need to power during an outage or for your activity. Don’t forget lights, phone chargers, and medical devices.
Find Wattage Ratings: For each appliance, look for its wattage rating. This is usually on a label or in the owner’s manual. If only amperage (amps) and voltage (volts) are listed, you can estimate wattage using the formula: Watts = Amps x Volts (typically 120V for household appliances).
Identify Starting Wattage Needs: For motor-driven appliances, estimate the starting wattage. A common rule of thumb is to multiply the running wattage by 2 or 3. If you can’t find specific starting wattage, assume a higher surge.
Calculate Total Running Wattage: Add up the running wattages of all the appliances you want to power simultaneously.
Determine Highest Single Starting Wattage: Identify the appliance with the highest starting wattage requirement on your list.
Add Running Wattage to Highest Starting Wattage: Your required generator wattage will be your total running wattage PLUS the highest single starting wattage. You don’t add all starting wattages together because appliances usually start at different times.

Example: You want to power a refrigerator (600 running watts, 1800 starting watts), a few lights (100 total running watts), a TV (200 running watts), and a phone charger (20 running watts).

Total Running Wattage: 600 + 100 + 200 + 20 = 920 watts

Highest Starting Wattage: Refrigerator at 1800 watts

Minimum Generator Size: 920 (running) – 600 (refrigerator running) + 1800 (refrigerator starting) = 2120 watts. A 2200-2500 watt generator would likely suffice for these items. Always round up to the next available generator size.

It’s always better to slightly overestimate your needs to give yourself a buffer. Remember that a generator running at or near its maximum capacity constantly will be less fuel-efficient and endure more wear and tear.

Key Features and Considerations

Beyond the basic type and wattage, several other features and considerations will influence your final generator choice.

Fuel Type and Capacity

Gasoline: Widely available, but has a limited shelf life (3-6 months without stabilizer). Best for portable use.
Propane (LP): Longer shelf life, burns cleaner, and can be stored indefinitely in tanks. Often used for dual-fuel or standby generators.
Natural Gas: Continuous fuel supply (if you have a natural gas line), no need for refueling. Exclusively for standby generators.
Diesel: More fuel-efficient than gasoline, longer engine life, but diesel generators are typically more expensive and heavier. Common for commercial or very large residential needs.
Fuel Tank Size: A larger tank means longer run times between refueling. Consider your expected average run time.

Noise Level (Decibels – dB)

Generators can be noisy. Noise is measured in decibels (dB), and lower numbers are better. For reference, normal conversation is around 60 dB. Inverter generators are significantly quieter (often in the 50-60 dB range) than conventional portable generators (often 70+ dB). Standby generators, while powerful, are usually installed further from living spaces, mitigating their noise impact.

Starting Mechanism

Recoil Start (Pull Start): Standard on most smaller portable generators. Requires manual effort.
Electric Start: A push-button start, often powered by a small battery. Much more convenient, especially for larger units.
Remote Start: Allows you to start the generator from a distance using a key fob.
Automatic Start: Exclusive to standby generators, this feature senses a power outage and starts the generator automatically. Generator Buying Guide

Outlets and Connectivity

Check the types and number of outlets provided. Ensure they match your needs. Common outlets include:

120V AC household outlets (NEMA 5-15R or 5-20R)
120V/240V AC twist-lock outlets (NEMA L14-30R) for connecting to a transfer switch
USB ports for charging small electronics

Also, consider if you need a GFCI (Ground Fault Circuit Interrupter) protected outlets, which are crucial for safety in wet conditions or on job sites. Generator Buying Guide

Portability and Weight

If you need a portable generator, consider its weight and whether it has wheels and a handle for easy transport. Inverter generators are often the most lightweight option for their power output. Generator Buying Guide

Automatic Transfer Switch (ATS)

For standby generators, an ATS is essential. It automatically detects power outages, starts the generator, transfers the electrical load, and then reverses the process when utility power returns. For portable generators, a manual transfer switch (MTS) and a power inlet box are recommended for safely connecting to your home’s electrical system. Generator Buying Guide

Safety Features

Low-Oil Shutoff: Prevents engine damage by automatically shutting down the generator if oil levels drop too low. Generator Buying Guide
Overload Protection: Protects the generator and connected appliances from damage by shutting off power if the load exceeds capacity. Generator Buying Guide
CO Sensor: Some newer generators include carbon monoxide (CO) sensors that automatically shut down the unit if dangerous levels of CO are detected. This is a critical safety feature, especially for portable generators. Generator Buying Guide
Spark Arrestor: Required for use in national parks and forests to prevent sparks from escaping the exhaust and starting fires. Generator Buying Guide

Maintenance Requirements

Like any engine, generators require regular maintenance. This includes oil changes, spark plug replacement, air filter cleaning/replacement, and fuel system checks. Consider the ease of maintenance and the availability of parts and service for your chosen brand. Generator Buying Guide

Installation and Safety Guidelines

Proper installation and adherence to safety guidelines are paramount when operating a generator. Ignoring these can lead to dangerous situations, including carbon monoxide poisoning, electrocution, and fire. Generator Buying Guide

Carbon Monoxide (CO) Poisoning

Generator exhaust contains carbon monoxide, an invisible, odorless, and deadly gas.NEVER operate a generator indoors, in a garage, carport, or near open windows or vents.

Always place the generator outdoors in a well-ventilated area, at least 20 feet away from your home, with the exhaust pointed away from windows and doors.
Install battery-operated CO detectors with digital displays in your home. Generator Buying Guide

Electrical Safety

Never ‘backfeed’ your home’s electrical system. Backfeeding involves plugging the generator directly into a wall outlet. This can send power back into the utility lines, endangering utility workers and potentially causing fires or electrocution. Generator Buying Guide
For home backup, use a properly installed manual transfer switch or an automatic transfer switch. Hire a qualified electrician for installation. Generator Buying Guide
Use heavy-duty, outdoor-rated extension cords that are appropriately sized for the load. Inspect cords for damage before use.
Ensure the generator is properly grounded. Generator Buying Guide

Fuel Safety

Store fuel in approved containers in a cool, dry, well-ventilated area, away from living spaces and heat sources.
Never refuel a hot or running generator. Allow it to cool down before adding fuel.
Do not overfill the fuel tank.
Propane tanks should always be stored and used upright.

General Operation and Maintenance

Read the owner’s manual thoroughly before operating your generator.
Perform regular maintenance as recommended by the manufacturer.
Test your generator periodically (e.g., monthly) to ensure it starts and runs correctly.
Keep children and pets away from the generator during operation.
Ensure the generator is on a level surface. Generator Buying Guide

Generator Sizing for Specific Scenarios

Let’s refine our understanding of generator sizing by looking at common use cases.

Small Portable Generators (1,000-3,000 Watts)

Use Case: Camping, tailgating, small RVs, powering a few essential items during a short outage.
What it Powers: Lights, phone chargers, small electronics, a few fans, a small refrigerator (inverter models are best for sensitive electronics).
Considerations: Prioritize portability, quiet operation (inverter models), and fuel efficiency.

Medium Portable Generators (3,000-7,500 Watts)

Use Case: Backup power for essential home circuits, job sites, larger RVs.
What it Powers: Refrigerator, freezer, sump pump, furnace fan, lights, TV, microwave, power tools.
Considerations: Electric start is a plus, consider dual fuel for flexibility, ensure adequate outlets for your needs. Generator Buying Guide

Large Portable Generators (7,500-15,000+ Watts)

Use Case: More extensive home backup (potentially powering most appliances, excluding central AC), demanding job sites.
What it Powers: Multiple refrigerators, well pump, furnace, most lights, entertainment systems, some larger power tools, potentially a window AC unit.
Considerations: Requires a manual transfer switch for home connection, fuel consumption will be higher, consider noise levels. Generator Buying Guide

Standby Generators (8,000-22,000+ Watts for Residential)

Use Case: Whole-home backup, powering central air conditioning, critical medical equipment, ensuring continuous power without manual intervention. Generator Buying Guide
What it Powers: Entire home or designated critical circuits, including central AC, electric range, well pump, and all standard appliances. Generator Buying Guide
Considerations: Professional installation is mandatory, ongoing maintenance, fuel source (natural gas or LP), noise mitigation. Generator Buying Guide

Budgeting for Your Generator

The cost of a generator can vary significantly based on its type, wattage, features, and brand. It’s important to consider not just the upfront purchase price but also installation (for standby units), fuel costs, and ongoing maintenance.

Portable Generators: Typically range from $400 for small inverter models to $2,500+ for large, powerful conventional units.
Inverter Generators: Generally $700 – $4,000, depending on wattage and features.
Standby Generators: Unit costs can range from $3,000 to $10,000+, with professional installation adding another $2,000 to $8,000+ depending on complexity (e.g., running gas lines, electrical work).
Fuel Costs: Factor in the cost of gasoline, propane, or diesel, especially for extended use. Natural gas offers a continuous supply but is still a utility cost.
Maintenance: Budget for oil changes, filter replacements, and potential service contracts for standby units. Generator Buying Guide

Remember that a generator is an investment in peace of mind and protection against power disruptions. While the initial outlay might seem substantial, the benefits of continuous power during an emergency often outweigh the cost. Generator Buying Guide

Warranties and Customer Support

Before making a purchase, investigate the manufacturer’s warranty. A longer warranty period often indicates a manufacturer’s confidence in their product’s durability. Also, consider the availability of customer support and authorized service centers in your area. This will be crucial if you encounter any issues or require parts and maintenance. Generator Buying Guide

Reputable brands often have extensive dealer networks and readily available technical assistance. Reading reviews from other users can also provide insight into real-world reliability and customer service experiences. Generator Buying Guide

Making Your Final Decision

With all the information gathered from this comprehensive generator buying guide, you’re now well-equipped to make an informed choice. Revisit your initial needs:

What do you absolutely need to power? (This determines wattage.)
Where will you use it? (Indoors/outdoors, home/portable – determines type.)
How often do you anticipate using it? (Influences fuel type, durability, and features.)
What’s your budget? (Helps narrow down options.)
Are noise levels a concern? (Points towards inverter or careful placement.)

By systematically addressing these questions and using the detailed information provided, you can confidently select a generator that will provide reliable power for years to come, ensuring comfort, safety, and continuity when the grid goes down or when you’re off the grid entirely. Generator Buying Guide

Questions?