Generator sizing Last reviewed June 2026

Portable vs Standby Generator: Which Size Do You Need?

By the WhatSize editorial team 5 min read Standards-reviewed

TL;DR

Choose a portable generator (3,500-7,500W) for occasional outages and a budget under $1,500. Choose a standby generator (14,000-22,000W) for automatic backup, whole-home coverage, and if you have medical needs or frequent outages.

Looking for a different size? See What Size Generator for a 2,000 Sq Ft House? or browse all generator sizing guides.

Portable vs Standby: The Key Difference

The fundamental difference is not just size — it's how the generator connects to your home. A portable generator sits outside, requires manual setup during an outage, and connects via extension cords or a manual transfer switch. A standby generator is permanently installed, connected to your home's electrical panel, and turns on automatically within seconds of a power outage.

Portable generators are typically 3,500-7,500W and cost $400-1,500. Standby generators start at 7,500W (rare) and go up to 22,000W+, costing $2,000-6,000 plus installation ($1,000-2,500). The standby generator's value is convenience and automation — you don't have to go outside in a storm to start it.

For sizing: a portable generator powers select circuits (fridge, furnace, lights, well pump). A standby generator powers your entire home including central AC, electric stove, and dryer.

Top picks for this size

BEST OVERALL

DuroStar DS13000MX 13,000W Dual Fuel #ad

13,000W, Dual Fuel, Electric Start, Whole Home Backup

★★★★☆ 4.6 · 177+ ratings

Dual Fuel (Gas/Propane)13,000W PeakElectric Start

$899 approx

Check price

MID-RANGE

Westinghouse 5000W Dual Fuel Inverter #ad

★★★★☆ 4.7 · 19.3K+ · $949

Amazon

These Amazon-available picks meet the calculated spec. For region-specific or licensed contractor-installed options, consult a local professional. See our Disclaimers.

Which Generator Type Is Right for You?

Choose portable (3,500-7,500W, $400-1,200) if: outages are rare (1-2 per year), budget is under $1,500, you have a manual transfer switch or extension cords, you want a generator you can take camping or to job sites
Choose standby (14,000-22,000W, $3,000-6,000) if: outages are frequent or long (3+ days), you have medical equipment that can't lose power, you want automatic reassurance, you have a propane or natural gas line
Consider a hybrid approach: a portable 3,500W now for essential circuits, upgrade to standby later if needed

Frequently asked questions

Portable vs standby generator — which is better?

No. Standby generator installation requires a licensed electrician for the automatic transfer switch and electrical connections, and often a plumber/technician for gas line installation. Total installation cost is typically $1,500-3,000.

Do standby generators require maintenance?

Yes. Standby generators have automatic weekly self-tests (about 15 minutes), but still need annual maintenance including oil changes, spark plug replacement, and battery checks. Plan for $200-400/year in maintenance costs.

What's the lifespan of a portable vs standby generator?

A well-maintained portable generator lasts 2,000-3,000 hours of use (10-15 years for typical home backup). A standby generator lasts 15-25 years with proper maintenance. Standby generators also have better resale value if you move.