Portable, standby, and the option in between

Search the comparison and you get two columns. A portable at $500 to $2,500 that you wheel out and feed with petrol, and a standby at $9,000 to $18,000 installed that starts itself within half a minute.

There is a third arrangement that borrows most of the standby’s usefulness for close to the portable’s price, and it rarely appears in those tables because the people publishing them sell standby units.

The portable, wired in properly

The arrangement is a portable generator, a power inlet box mounted on the outside wall, a short run of cable to the panel, and either an interlock kit or a small manual transfer switch.

The interlock is the clever, cheap part. It is a metal plate that makes it mechanically impossible to have the main breaker and the generator breaker closed at the same time, which is exactly what a transfer switch achieves electrically. You roll the generator out, plug one cord into the inlet, kill the main, flip the generator breaker and the house circuits are live from the machine.

What that buys over extension cords is everything hardwired. The furnace, the well pump, the fixed lighting, the garage door. Those are the things a cord cannot reach and the things that make an outage genuinely unpleasant.

What it costs against a standby

The inlet, the interlock and the electrician are usually a modest job, considerably below the transfer switch alone on a standby install, and there is no pad, no gas connection and no gas permit.

So the comparison is a few hundred to a couple of thousand all in, against roughly ten to fifteen thousand. For that difference you give up three things, and they are worth naming honestly.

What you give up

Automatic starting is the big one. A standby notices the outage and runs within half a minute, including when the house is empty or everyone is asleep. The portable route needs a person, outdoors, in whatever weather caused the outage.

Fuel endurance is the second. A standby on natural gas runs as long as the gas keeps flowing, which during most outages is indefinitely. A portable runs on petrol, needs refuelling every several hours, and petrol is exactly what becomes hard to buy during a regional outage.

Capacity is the third, though less than people assume. A large portable will carry a well-chosen list of circuits comfortably. It will not carry central air conditioning and an electric range at once, which is the gap the generator size calculator is there to make visible before you buy rather than after.

Choosing by outage pattern, not by preference

The question that actually decides it is what your outages look like.

Brief and rare, a few hours once or twice a year, and the portable route is hard to argue with. Nobody is going to feel the absence of automatic transfer for three hours a year, and the money saved is substantial.

Long and frequent, or a house with medical equipment, a sump pump that must run, or occupants who cannot safely manage a generator in the dark, and the standby earns its price. So does a property that is regularly empty, since nothing about the portable arrangement happens without a person present.

Run both as numbers rather than as impressions. The generator cost calculator will take an installed standby figure apart, and the honest portable comparison is the machine plus the inlet work plus the fuel you will actually burn over a decade.

The thing neither column mentions

Whichever route you take, the dangerous shortcut is the same one, and it is common enough to be worth stating plainly.

Running a cord from a generator into a dryer outlet to backfeed the panel puts exposed live pins on one end of that cord and can push power back onto the utility line, where somebody is working to restore your supply. The interlock exists precisely because it makes that impossible, and it costs far less than the fine, never mind the alternative.