Buying guide · Generators
The buying mistake on whole-house generators is reversing that order. Dealers will happily quote a 24 kW machine for a 9 kW problem — or a 10 kW machine for a heat pump that will never start.
Summary
This whole-house generator buying guide walks the sequence a good installer already uses: list the loads you refuse to lose, check the gas or propane supply, sort out the transfer switch, and walk the lot before you fall for a brochure. Skip a step and you buy kilowatts you cannot feed — or a handsome enclosure that fails inspection. Read it before the dealer visit, not after.
The first time most people price one of these, it is two days before a storm with a name, standing in a kitchen that still hums, phone in one hand and a dealer’s website in the other. That is the worst possible frame of mind for a five-figure decision, and the dealers know it. So here is the sequence a good installer already uses, written down for a calmer afternoon. The Home Backup is a desk, not a dealer — we do not sell named standby machines and we will not invent a generator affiliate hop. Skip a step in this order and you buy kilowatts you cannot feed, or a pretty enclosure that will not pass inspection. Which class of machine (air-cooled 9–12 kW versus liquid-cooled 20 kW and up) comes after the load list, not before: best standby types once you know the job. Money: cost.
Start with the circuits you refuse to lose, not the square footage. Walk the house and be honest about it: the refrigerator and the chest freezer with a summer’s worth of food in it, the well if that is your only water, the sump that keeps the carpet dry, the furnace or air handler, a few lights, the modem. That list is a different machine from “the house feels like the grid, including both condensers and the dryer.” Write running watts from nameplates, or a clamp meter if you have one, and then write starting watts — because compressors and motors care about the first second, and the starting spike on a heat pump can dwarf the running number. When a dealer only talks running kilowatts, they are selling a brochure.
There are honest ways to make a smaller machine cover a bigger house — soft-start devices on condensers, load-shed modules, managed panels — and they are how an air-cooled 10–12 kW class covers a house that would otherwise demand 20 kW. They are also how you stay truthful with yourself: the second outdoor condenser may sit dark during an outage, and that’s fine, if heat or the well was the actual job. Don’t let the phrase “whole house” talk you into a liquid-cooled plant you will not maintain.
One more thing the brochure won’t volunteer: altitude and temperature shrink the same nameplate. A mountain house is not a sea-level house, so ask for the derate in writing. When two quotes disagree by a full class, the useful argument is the load list and whether the air conditioning is locked out — not whose badge is on the lid. The Home Backup does not stamp load calculations. Hire the electrician who will pull the permit.
Natural gas is the set-it-and-forget-it fuel, as long as the utility keeps the pipe pressurized — and in many wind and ice events it does, humming along under a street where the power lines came down. That is a pattern, not a law of physics. Confirm the meter capacity, because a generator that wants more gas per hour than the meter and pipe can deliver will sag, hunt, and drop the well right when you need it. Upsizing the gas service is a real line on the bill — see the gas work on the cost page.
Propane is the fuel you own. There is a tank in the yard with a gauge on it, and nobody at a utility can turn it off — but nobody refills it in an ice storm either, and an undersized tank can weather-lock in deep cold just when the draw is highest. Propane is the usual answer when there is no gas main in the street, or when you want fuel on your own property after a utility gas outage. Budget the tank, the trench, and the fill.
Gasoline belongs in the portable conversation, not on a pad you expect to start itself at 3 a.m. It is easy to buy the day before landfall and miserable to store for the year after — it goes stale, varnish gums the carburetor, and a red five-gallon can in the garage is both a fire risk and about an evening of runtime. Dual-fuel portables that also drink propane are the compromise for people who chose the driveway over the pad. Still deciding between the driveway and the pad? Read standby vs portable before you shop fuel cans.
| Fuel | Typical use | Strength | Failure mode |
|---|---|---|---|
| Natural gas | Automatic standby on a pad | No jerry cans; utility often still flows in storms | Meter/pipe too small; rare gas outages; you do not “own” the supply |
| Propane | Automatic standby, or dual-fuel portable | On-site energy; works off the gas utility | Tank empty or iced; delivery lag; trench and tank cost |
| Gasoline | Portable generators | Easy to buy the day before a storm | Stale fuel, carburetors, fire storage, short runtime per can |
Here is the part nobody photographs for the brochure: the automatic transfer switch — the box that senses the outage and moves your house onto the generator — is the real product. The engine is the accessory. Without a listed transfer method you do not have whole-house backup; you have a loud box in the yard and a dangerous temptation to backfeed. A service-entrance transfer switch sits at the meter and can move the whole panel, if the generator and gas line can feed it. A load-shed kit drops the big 240 V appliances so a smaller engine stays alive. A managed panel — smart breakers, priority circuits — is a third way to keep an air-cooled machine honest. All of it is licensed work in almost every US jurisdiction.
For portables, the legal version of the same idea is an inlet box on the wall plus an interlock in the panel, or a listed manual transfer switch. The interlock is just a sliding plate, and it does one sacred thing: it makes it physically impossible for the utility main and the generator breaker to be on together, which is what keeps a line worker alive on your street. Extension cords to the fridge and a lamp are a smaller, legal-enough job — if the generator stays outdoors and the cords are rated. They are not a whole-house design. And if the phrase “suicide cord” is new to you, hire the electrician before you buy the engine.
Don’t let a salesperson wave off the conversation about 120 versus 240, bonding, and whether the transfer switch is service equipment. Those details decide inspection day. They also decide whether a future battery inlet can ride the same wiring — different product, same electrician. If you are comparing a pad plant to a split-phase battery, the named kit on this site is the Anker SOLIX F3800, discussed as a class alternative, not a generator.
The Home Backup is not your inspector, gas fitter, structural engineer, or HOA architectural committee — and all four of them can kill this project after you have fallen for it. Local noise rules, setbacks, and covenants sink otherwise perfect machines. A pad under a bedroom window, or blocking a meter, or inside the manufacturer’s clearance diagram will fail even when the kilowatts were right. So walk the lot with a tape measure and the installation diagram before you sign a deposit, and ask the dealer straight out who pulls the permit. If the answer is “you file it,” price that work, and the rework when it comes back red-inked.
HOAs argue about enclosures, paint, screening, and whether a generator counts as “equipment.” Some allow a machine behind landscaping; some ban it flat. Get the covenant answer in writing before the concrete truck is scheduled. Your neighbors will hear the weekly exercise run — pick a time window the manual allows and the street can live with. Placement is also a carbon monoxide question: exhaust pointed away from windows and doors, never into a fenced corner that traps fumes.
And think about the yard the way winter thinks about it. A machine in a swale will drown. A machine that needs a snow tunnel dug to it will not start. Flood lines, drift patterns, and the dog’s path all matter more than the brochure photography. The pad, the airflow around a liquid-cooled radiator, the manufacturer’s mounting kit — that is install, not extras you discover on inspection day. If the only legal spot doesn’t exist on your lot, you do not have a standby project. You have a portable-plus-inlet project, or a battery project, and that’s fine.
If this list already feels like more project than you wanted, that is worth knowing now, in the calm. An expandable battery and an inlet box may be your answer. Start at the battery guide, or go straight to hours-of-essentials at power stations for home backup. Featured carts if you leave the engine aisle: Jackery, BLUETTI, Anker SOLIX. Physics fork: battery vs standby.
The Home Backup is not your AHJ, gas fitter, or structural engineer. Nothing here is a permit, a load calculation, or a blessing to backfeed a dryer outlet. We do not sell standby brands as affiliates. Method: how we review. Money: affiliate disclosure. Desk scope: about. If a sentence on this page is wrong for your code, write contact — we will not remote-approve a panel.
One small thing to do tonight, before any dealer visit: walk the yard with a tape measure and write your load list on paper — the well, the sump, the freezer, the furnace. Tomorrow-you, sitting across from a salesperson, will be glad the list got there first.
