5-year ownership cost

Last updated: September 28, 2026 (CT). The article portable vs standby explains the classes. This page prices them with your running load and how often the grid actually dies.

Dealers sell standby on “never think about it.” We sell a break-even hour count. Portable cash is the machine + gasoline at the site fuel rule + oil every 50 hours. Standby cash is install + a yearly service visit. Natural-gas standby fuel is usually cheap per hour versus hauling cans; we still do not pretend NG is free — we leave that line at service-only unless you type a fuel add-on into the portable side by raising gas price.

Typical running watts during an outage

Grid-out hours per year (your history)

Gasoline $/gal

Portable you would actually buy ($)

Standby installed ($)

Standby service $/year

How to pick the outage-hours input

Do not use a national average. Use your last five winters. A rural well-pump ranch that loses a day of ice every other year is ~12–24 hours/year. A city feeder that blinks 40 minutes twice a summer is ~2 hours/year — standby almost never wins that math unless you have medical loads or a $4,000 used automatic unit. A Gulf Coast house that ate 120 hours in one hurricane year should enter 120, not 20, and should also open the storm runbook for cans.

This TCO ignores the value of not dragging a 200 lb open-frame through snow, and it ignores HOA noise fines. Price those with lot-line noise and your own back. If sequenced need is over ~10 kW or you want central AC without a ritual, standby starts winning on labor even when the five-year cash still favors portable.