Portable vs. Standby Generators: an Honest Cost-Benefit
A $1,100 portable covers most outages; a $12,000 standby covers all of them without you touching anything. Where each one actually makes sense.
Updated July 15, 2026
The standby-generator industry would like you to believe a portable is a toy, and the portable aisle would like you to believe a standby is a boat payment bolted to your foundation. Both are wrong. The honest split comes down to three questions: how often you lose power, for how long, and whether anyone needs electricity when nobody's home to pull a starter rope.
What each one actually is
A portable in the home-backup class (5,000–12,500 watts, $500–$1,500) lives in the garage, gets wheeled out during an outage, and feeds the house through cords or — much better — an inlet with an interlock. You start it, you refuel it every 8–12 hours, you manage what runs. A standby (typically 10–26 kW, $9,000–$14,000 installed) is permanently wired with an automatic transfer switch, fed by natural gas or a propane tank, and takes over by itself within seconds, whether you're home, asleep, or on vacation.
The math over ten years
| 7,500W portable + interlock | 22kW standby, installed | |
|---|---|---|
| Up-front | $1,100 + $700 install | $9,000–$14,000 |
| Fuel/energy per outage day | $30–$60 gasoline | $20–$80 utility gas/propane |
| Annual upkeep | $30–$50 (oil, stabilizer) | $200–$400 service contract |
| Ten-year total (rough) | $3,000–$4,500 | $12,000–$18,000 |
| Works when you're away | No | Yes |
| Runs central AC / whole house | Partially, with load management | Yes |
Where the standby genuinely earns its price
- Medical equipment that cannot tolerate an hour of downtime — oxygen concentrators, powered home-care beds, refrigerated medication.
- Homes in multi-day-outage territory (hurricane and ice-storm country) where refueling a portable every ten hours for a week gets genuinely hard.
- Sump-pump-dependent basements plus owners who travel — a flooded basement while you're away costs more than the generator.
- Anyone physically unable to wheel out a 200 lb machine and pull-start it in a storm.
Where the portable is the smarter buy
- Outages measured in hours, a few times a year — the overwhelmingly common case.
- Budgets under $2,000 — a good portable plus a professionally installed interlock beats a cheap standby every time.
- Anyone who also wants the machine for camping, job sites, or the RV — a standby is married to your slab.
Frequently asked questions
Is a standby generator worth it?
It's worth it when outages are frequent or multi-day, when someone depends on powered medical equipment, or when the house must stay powered unattended (sump pumps, pipes in freeze country, pets). For a few short outages a year, a 7,500W-class portable with an interlock delivers most of the benefit for roughly a quarter of the ten-year cost.
How much does a standby generator cost installed?
The machine is $5,000–$7,000 for a typical 18–26 kW air-cooled unit, but the realistic project total is $9,000–$14,000 once you add the automatic transfer switch, pad, gas plumbing, electrical work, and permits. Complex gas runs or panel upgrades push it higher. Get at least two itemized quotes.
Can a portable generator run a whole house?
A 9,500–12,500-watt portable feeding a 50-amp inlet can run most of a typical house if you manage loads — the usual sacrifice is central air conditioning and electric heat, whose compressors and elements are the two biggest draws. 'Everything, including 4-ton AC, no thought required' is standby territory.
How long can a standby generator run continuously?
On natural gas, effectively as long as the utility supplies gas — manufacturers recommend a check and oil change after every 100–200 hours of continuous running. On propane, runtime is set by tank size: a 500-gallon tank runs a mid-size unit roughly a week at moderate load.