How to Choose the Right Generator for Your Home

Why Choosing the Right Generator Matters

Buy too small and your generator will trip its breaker or run hot under load. Buy too large and you'll overspend on the unit, burn more fuel than necessary, and carry around a machine that's heavier than it needs to be. Getting the size right is the single most important decision — and it's one most buyers get wrong because they go by gut feel rather than math.

In this guide we'll walk through generator types, how to calculate your true load, fuel options, transfer switch requirements, and key features to look for. By the end, you'll know exactly what to buy.

Step 1: Understand the Generator Types

There are three main categories of home generators. Each suits a different budget, use case, and installation complexity.

Portable Generators

Portable generators are the most popular choice for homeowners. They run on gasoline (or dual-fuel propane/gas), range from 2,000W to 12,000W, and cost between $400 and $2,500. They must be operated outdoors at least 20 feet from any door or window due to carbon monoxide risk, and they require manual startup.

• Best for: Occasional outages, renters, homeowners on a budget
• Typical size: 3,500W–8,000W covers most essential loads
• Key downside: Manual operation, requires fuel storage, noisy

Inverter Generators

Inverter generators produce "clean" power (low total harmonic distortion) that is safe for sensitive electronics like laptops, phones, and medical devices. They are quieter and more fuel-efficient than conventional portable generators but typically offered in smaller sizes (1,000W–7,000W) and at a higher price per watt.

• Best for: Sensitive electronics, camping, quiet neighborhoods
• Typical size: 2,000W–4,000W for light-to-moderate loads
• Key downside: More expensive per watt, smaller maximum output

Standby Generators

Standby generators are permanently installed, run on natural gas or propane, and start automatically within seconds of a power outage. They range from 7,500W for essential-load coverage up to 20,000W+ for whole-home backup. Installation requires a licensed electrician and an automatic transfer switch (ATS), adding $1,500–$5,000 in labor and materials on top of the unit cost ($3,000–$15,000+).

• Best for: Frequent outages, medical equipment dependency, whole-home coverage
• Typical size: 11,000W–22,000W for a typical 2,000 sq ft home
• Key downside: High upfront cost, requires professional installation

Step 2: Calculate Your True Load

Most buyers size their generator based on the largest appliance they want to run — usually a central air conditioner or well pump. While those are important anchor loads, you need to account for everything you plan to run simultaneously.

The correct formula is:

1. List every appliance you want to power during an outage.
2. Add up their running watts.
3. Find the single appliance with the highest startup surge watts (usually an AC, refrigerator, or pump motor).
4. Add the surge delta (startup watts minus running watts) for that appliance to your total running watts.
5. Multiply by 1.20 (20% safety buffer).

That final number is your minimum generator wattage. Our Generator Size Calculator handles all of this automatically — just check the appliances you want to run and it outputs your required wattage with the safety buffer built in.

Step 3: Choose Your Fuel Type

Fuel type affects runtime, storage, availability, and long-term maintenance. Here's a quick comparison:

For most homeowners buying a portable, dual-fuel is the best choice — gasoline is easy for short outages, propane stores indefinitely for longer-term emergencies.

Step 4: Understand Transfer Switches

To power hardwired circuits (furnace, well pump, hardwired lighting), you need a transfer switch. There are two types:

• Manual Transfer Switch (MTS): A sub-panel installed by an electrician that lets you manually switch selected circuits to generator power. Cost: $500–$1,500 installed. Required for portable generators powering hardwired loads.
• Automatic Transfer Switch (ATS): Detects a utility outage, starts the standby generator, and switches the load automatically. Required for all standby generators. Cost: Typically included with standby unit installation.

Never backfeed your home's panel by plugging a generator into an outlet. Backfeeding is illegal, destroys your generator, and can electrocute utility workers restoring power. Always use a proper transfer switch or a generator with a dedicated power transfer kit.

Step 5: Features Worth Paying For

• Electric start: Essential for standby generators; very convenient for portables over 5,000W
• CO shutoff: Required by law in many states; automatically shuts the generator off if carbon monoxide reaches dangerous levels
• Low-oil shutoff: Protects the engine; standard on most modern units
• Load sensing / economy mode: On inverter generators, throttles down when loads are light, saving fuel
• Parallel capability: Inverter generators can be paired for double the output
• GFCI outlets: Required for outdoor use; standard on newer models
• Run time at 50% load: A better runtime benchmark than "at rated load" — always compare this figure across models

Putting It All Together

Here's the quick decision tree for most homeowners:

1. Use our Generator Size Calculator — enter your appliances and get your required wattage.
2. If your load is under 10,000W and outages are occasional → buy a dual-fuel portable with electric start and CO shutoff. Budget $700–$1,500.
3. If outages are frequent or you have medical equipment → consider a standby generator. Get quotes from at least two licensed electricians.
4. Add a transfer switch or interlock kit so you can power hardwired circuits safely.
5. Store extra fuel (with stabilizer) and test your generator every 3 months under load.