Standby vs portable: two different products
A standby generator and a portable on a manual hookup both make electricity, but they're really selling different things: the standby sells not being there, it starts itself, feeds itself, and covers the house while you're away, while the portable sells capacity per dollar, with you as the transfer switch. Here's the honest comparison, using the installed-cost bands from our cost guide and the consumption data from our fuel & runtime guide.
What each route costs, all-in
| Route | Typical all-in | What the money covers |
|---|---|---|
| Standby, ~10 kW class | $6,500–$11,000 | Generator, automatic transfer switch, pad, gas and electrical work, permits, professionally installed, comes on by itself. |
| Standby, 18–22 kW class | $9,500–$15,000 | Whole-home coverage including central air, in the most common size band. |
| Standby, 24–26 kW class | $11,000–$18,000 | Large or all-electric homes, multiple AC units; complex sites can run higher. |
| Portable + interlock and inlet | Generator $949–$2,699, plus $400–$850 installed hookup | You start it, plug in one cord, flip the interlock, and choose which circuits to run. |
| Portable + GenerLink | Generator as above, plus $774–$1,120 | Meter-mounted transfer device installed through participating utilities; the 40-amp version caps continuous output at 9,600 W no matter how big the generator is. |
Our cost guide totals the portable route at roughly $1,400–$3,500 all-in, about a fifth of the smallest standby install. The recurring bills differ too: a standby carries annual professional maintenance in the $200–$650 range, while a portable's upkeep is mostly your own time, oil, stabilised fuel, and actually running it now and then so it starts when it matters.
The outage itself: what you actually do
Standby. The power fails; seconds later the generator starts and the transfer switch moves the house over. You do nothing, including if nobody is home, which is the entire point for a house with a well pump, a sump pump, medical equipment, or a furnace that protects pipes in January. The unit exercises itself weekly for a few minutes so it stays ready, a sip of fuel our fuel guide counts as negligible.
Portable + interlock/GenerLink. The power fails; you wheel the generator outside, connect the cord, start the engine, then switch the house over and manage loads by hand, the AC, dryer, and range don't get to gang up unless your generator says so. When utility power returns you reverse the sequence, and during a long outage you refuel on the generator's schedule, not yours. None of this is hard, but all of it requires someone home, awake, and able-bodied. Connection hardware like an interlock exists to prevent backfeeding the grid; have a licensed electrician install and walk you through the switching order, and follow the generator manufacturer's placement and exhaust instructions exactly.
The managed outage: the cheaper middle path
Between "do nothing" and a standby install sits the managed outage: battery-backed sump pumps and a closed fridge carry the opening hours, then a portable or inverter generator runs the critical circuits while big loads take turns. It is not automatic, and it is not whole-home by default, but for a house with someone capable at home it can deliver most of the protection for a fifth of the money.
The full playbook, including the load tiers, sizing split, safety rules, and the cases where standby is still the right buy, is in the managed outage guide.
Runtime and fuel logistics
On natural gas, a standby runs as long as utility gas flows, no runtime table, no deliveries. On propane it's a tank problem: our runtime table works a Generac Guardian 14 kW at half load to about 110 hours (4.6 days) on a 250-gallon tank at 80% fill, and a 22 kW to about 79 hours on the same tank, bigger generators drink faster, which is an argument for sizing to the load rather than the ego.
A portable carries hours, not days. From the model database: a Westinghouse iGen4500DFc inverter runs about 9 hours on its 3.4-gallon tank at half load, a DuroMax XP9000iH about 11 hours on 6.9 gallons, and a DuroMax XP13000EH about 8 hours on 8.3 gallons. A 5-gallon can therefore buys roughly another half-day for a big portable and well over half a day for a small inverter, and dual-fuel models can drink from a propane tank instead, stretching the same math. The trade is storage and freshness: stored gasoline needs rotation, and every refuelling is another trip outside in the weather that caused the outage.
Noise belongs in this section because it decides where the machine can live and how close the neighbours feel. Standby units in our database rate 61–69 dB; big open-frame portables rate 72–74 dB; inverter portables land at 52–68 dB, closing much of the gap at a higher price per watt.
Who each one fits
- Choose standby if outages are frequent or multi-day, the house is empty for stretches (travel, work, a vacation property), someone depends on powered medical equipment, or water and heat must protect themselves, a well pump, sump pump, and furnace blower don't care that you're on a plane. The automation is what the extra $5,000+ buys, and for these houses it's the product.
- Choose portable + hookup if outages are rare and short, someone capable is reliably home, and the load list is essentials: fridge, furnace blower, well pump, lights, a few outlets. At $1,400–$3,500 all-in it's rational insurance, and an inverter model keeps it neighbourly.
- Choose portable now, standby later if the budget is real but the house is a keeper: the interlock or GenerLink stays useful, and the portable becomes the backup's backup. Just don't let a "temporary" portable quietly become the plan for a house that's empty all winter.
Either way, size from the load list, not the brochure: run the sizing calculator, then check real models and their fuel ratings in the model database. This comparison is guidance, not electrical advice: transfer equipment touches your service entrance, and a licensed electrician should make the final call on hardware and hookup.
Sources & notes
- Installed standby totals, interlock and GenerLink prices, and maintenance ranges: TallyGauge cost guide (sources and dates listed there).
- Fuel consumption, tank runtime, and portable tank/runtime figures: TallyGauge fuel & runtime guide and the model database behind it.
- GenerLink availability and pricing vary by utility; the figures quoted are published prices from participating cooperatives listed in the cost guide.