What “whole home” actually means
Most people who say whole-home mean “everything I actually use”, and those are different requirements with very different prices.
The line is drawn by a small number of large loads. On Champion's published figures:
- Central air conditioning, 3 ton — 3,000–3,500W running, 5,000–6,000W starting
- Electric water heater — 3,000–4,500W
- Well pump, 1 HP — 1,000–2,000W running, 2,000–4,000W starting
Add an electric range or an electric dryer and the totals rise further. Any one of these eliminates every portable battery on this site and most mid-sized generators.
So the first question is not which machine. It is: which of those do you genuinely need running during an outage? For a great many households the honest answer is none of them — you can put on a sweater, shower at a friend's, and cook on a gas range — and that answer saves a great deal of money.
The load math
A genuine whole-house list, at the upper end of the published ranges:
| Load | Running W | Starting W |
|---|
| Central AC, 3 ton | 3,500 | 6,000 |
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| Well pump, 1 HP | 2,000 | 4,000 |
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| Refrigerator | 400 | 1,200 |
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| Freezer | 500 | 1,000 |
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| Furnace fan, ½ HP | 800 | 1,600 |
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| Sump pump, ⅓ HP | 800 | 1,600 |
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| Microwave | 1,200 | — |
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| Lighting and electronics | 300 | — |
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Champion Power Equipment's published wattage chart, upper end of each range. Sizing against the upper end is deliberate: a system that only works with the efficient appliance is not a backup system.
Running total: 9,500W. The largest single surge is the central air conditioner at 6,000W, so peak = 9,500 − 3,500 + 6,000 = 12,000W.
That is the number that pushes a household from a portable to either a 13,000W machine or a standby installation, and it is almost entirely driven by one appliance. Drop the central air conditioning and the same house needs 6,000W running with a 8,000W peak — a completely different and much cheaper machine. The sizing method in full.
Match the purchase to the outage
Capacity is not a preference. It falls out of two numbers: how long your power is usually off, and what you refuse to lose while it is.
| Your outage lasts | What has to keep running | Realistic product class |
|---|
| Critical load only, any duration | Fridge, furnace, sump pump, lights | 5,300W generator plus a transfer switch
See generators under $1,000 |
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| Everything except air conditioning | Above, plus a well pump and cooking | 9,500W dual-fuel generator
See the larger machines |
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| Genuinely everything, manually | Above, plus central air conditioning | 13,000W portable with a 50A transfer switch
Whole-house options |
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| Everything, automatically, nobody home | The whole service, starting itself | Standby generator on natural gas
Generac vs Kohler |
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The three routes
1. Selected circuits with a portable
A 5,000–9,500W dual-fuel generator plus a transfer switch or interlock kit, backing a chosen list. Delivers most of what an outage actually costs you, for a fraction of a standby installation.
What you give up: air conditioning, automatic start, and the requirement that somebody is home to run it.
2. Whole panel with a large portable
A 13,000W machine with a 50A transfer switch or an interlock kit, covering the whole panel including central air conditioning.
What you give up: automatic start, and you take on a serious fuel logistics problem — a machine this size consumes fuel in proportion to its output.
3. Standby installation
A permanently installed generator on natural gas or propane with an automatic transfer switch. It starts itself, transfers the house in under about thirty seconds, and on a gas main never runs out.
What you give up: a five-figure installed cost, a permit, a gas line and annual maintenance — and the machine does nothing between outages. What the installation involves.
What the fuel actually costs at this scale
What it costs to actually run
The sticker price of a dual-fuel generator is a fraction of what it costs you. The sticker price of a battery is nearly all of it. Here is the arithmetic, with the inputs stated so you can redo it with your own fuel price.
| Unit | Published consumption | Cost per hour | Cost per 24 h |
|---|
| 13,000W portable, heavy load, gasoline | ~1.2 gal/hr | $4.89 | $117.24 |
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| 9,500W portable, half load, gasoline | ~0.55 gal/hr | $2.24 | $53.74 |
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| Generac 24kW standby, half load, natural gas | 203 ft³/hr (about 2 CCF/hr) | Your gas rate × 2 CCF | Your gas rate × 48 CCF |
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| Generac 24kW standby, half load, propane | 2.53 gal/hr | $6.76 | $162.31 |
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Gasoline at $4.071/gal and propane at $2.674/gal (EIA weekly retail and residential series). Generac's natural gas and LP consumption figures are its published values for the 24kW Guardian. We do not convert the natural gas row into dollars because residential gas rates vary far too widely by region and season for an average to mean anything — multiply by the rate on your own bill. Portable consumption figures are working estimates at the stated load; your manual publishes its own.
The natural gas row is why a standby unit on a gas main is a different proposition: there is no volume to store, no trips, no rationing, and no cans in the garage. That, rather than automatic start, is often the real argument for standby.
The question that saves the most money
Ask it honestly: does the air conditioning have to run?
It is the load that doubles the requirement, and there are alternatives that a portable can handle. Champion puts a 10,000 BTU window unit at 900–1,200W running and 1,800–2,400W starting — a fraction of a central system, and enough to make one or two rooms genuinely comfortable.
Cooling the bedroom rather than the house is a legitimate outage strategy, and it moves a household from the 13,000W tier to the 5,300W one. If anyone in the house is medically vulnerable to heat that calculation changes, and it should — but for most people this is the single biggest lever available.
Before you commit
- Write the honest must-run list. Not the wish list. What actually has to work.
- Compute the peak using the wattage chart: running total, minus the biggest item's running watts, plus its starting watts.
- Look up your outage history. If your utility averages two hours a year, whole-home standby is an enormous purchase for an event you do not have.
- Get two itemized quotes if standby is on the table, and compare line items rather than totals. The gas line is where the difference hides.
- Price the portable alternative alongside them — a 9,500W dual-fuel machine plus a professionally fitted transfer switch — so you know what the automatic-start premium actually costs.
