What Does a Generac Generator Run On? A Bulk Standby Buyer's Cost Guide (and the 9% Quote That Almost Cost Us a Season)

August 2023, 6:40 AM

My phone rang before I'd finished my coffee. It was our biggest dealer — a 40-truck HVAC and electrical outfit two states over — and he wanted 30 Generac home standby units on the ground by the end of September.

Not "sometime this fall." By the end of September. He'd already presold most of them off a storm-season promotion and had customer deposits in hand. If the units didn't land, he was the one calling customers to explain, and we were the one he'd never buy from again.

I run procurement for an 85-person electrical supply company. I've managed our power equipment budget — ballpark $1.4 million a year — for six years, and I've negotiated with more than 40 vendors in that window. Every order goes into our cost tracking system, which is the only reason I can reconstruct what happened next with any real accuracy.

I thought I understood generators. I had about three weeks to find out I was wrong about the most basic thing: what they run on.

"It runs on gas" is not a specification

Here's the part that tripped me up. When a dealer says "it runs on gas," they might mean natural gas, liquid propane, gasoline, or diesel — and none of those are interchangeable at the point of sale.

If you're trying to answer "what does a Generac generator run on," the honest answer is: it depends on the product line, and the product line determines your entire installed cost.

• Home standby (Guardian and Protector series): natural gas or liquid propane. Air-cooled units run from about 10kW to 26kW. Liquid-cooled units start around 32kW and go past 48kW.
• Portable: gasoline, mostly. Dual-fuel portables will also take LP. The inverter portables run on gasoline.
• Commercial, industrial, and mobile: diesel is the default for the heavy stuff, though some commercial units are set up for natural gas or LP.
• Battery storage (like PWRcell): no fuel at all. It charges off solar or the grid.

Now the part that isn't on the front of the brochure. Air-cooled standby units are rated differently on propane than they are on natural gas. A 24kW unit makes 24kW on LP. On natural gas it's closer to 21kW. Same model number. Different output.

(Should mention: that's straight off Generac's own spec sheets — each model page on generac.com lists separate LP and NG ratings. Verify the specific model before you put a number in front of a customer.)

Where my assumption blew up

I assumed gas meant natural gas. Our territory is rural. A big chunk of it isn't on a gas main at all.

You'd think a distributor would know that. I didn't, not at the unit level. I learned never to assume fuel availability after we quoted 12 units to a dealer whose customers were all outside the gas service area. Those became propane jobs, which meant tanks, which meant tank permits, which meant a completely different installation scope.

And even where natural gas is available, the meter matters. A 24kW air-cooled unit pulls a few hundred thousand BTU/hr at full load. Plenty of residential gas meters and service lines aren't sized for that on top of a furnace, water heater, and range. The utility has to get involved, and that's a timeline you don't control.

Here's something vendors won't tell you: the published wholesale price list is a starting point, not a price. Real pricing tiers hinge on your stocking commitment, your annual volume, and whether you're buying into a program or cherry-picking SKUs. If you're only buying when a storm is forecast, you're paying the top tier and you're last in line for allocation.

Then the quotes came back

Two wholesale channels. Both legitimate. Both could get the product.

Channel A quoted about 9% less per unit. Lead time: five to six weeks, "subject to allocation."

Channel B quoted 9% more. Lead time: a firm three-week window, written into the acknowledgment, with a stocking program attached.

I went back and forth for four days. Nine percent on a 30-unit order is real money — a little over $14,000 on the deal. But the whole reason we had this order at all was a deadline that had already been sold to end customers.

The decision kept me up for two nights. On paper, A made sense. My gut said B.

The nine percent that almost cost us the season

I said "subject to allocation" and read it as "backorder risk." They heard "first-come, first-served among dealers in the region." We were using the same words and meaning different things, and I didn't find that out until week five, when our contact mentioned — casually, in an email signature chain — that the allocation hadn't cleared yet.

We ended up with 11 weeks on the calendar. The dealer's September commitment became an October apology tour.

That's when I went back to Channel B and paid for expedited freight on a partial shipment to salvage the back half of the order. The expedite fee stung. Missing the season would have stung a lot more.

Even after I approved the rush fee, I second-guessed it. Could I have negotiated it down? Did I overpay because I was panicking? I didn't relax until the first truck actually backed into the dock, on the date they said, with the units boxed exactly as specified.

What a bulk house generator order actually costs

This is the part people want. Here's what we saw on wholesale quotes we collected in Q4 2024. Treat it as a range, not a quote — pricing moves with allocation, freight, and season, and you should verify current numbers before you commit to anything.

• 10kW–14kW air-cooled standby: roughly $2,600–$3,900 per unit at wholesale, depending on fuel configuration and volume tier.
• 18kW–22kW air-cooled: roughly $4,000–$5,400.
• 24kW–26kW air-cooled: roughly $5,200–$6,400.
• Liquid-cooled 32kW–48kW: roughly $10,000–$18,000+, and the spread widens fast with enclosure and transfer switch options.

Prices as of that window; verify current rates with your supplier.

But the unit price is maybe 55–65% of the installed number a homeowner sees, and that ratio is where distributors get themselves in trouble. The rest lives in:

• Freight class and liftgate service (you will pay for liftgate, and you should budget for it)
• Transfer switch and any load management hardware
• Gas line sizing, meter upgrades, or LP tank and permitting
• Concrete pad, permits, inspection
• Damage claims and the labor to process them — we ran a 3.1% damage rate in 2023 and got it under 1% by changing carriers, not by changing suppliers
• Warranty administration time, which nobody quotes and everybody eats

The lowest quoted unit price is frequently not the lowest total cost. I've watched a "cheaper" channel end up 11% more expensive once freight, re-shipment, and damage replacement were in the spreadsheet.

Compliance items worth checking early

Standby power isn't just a product decision. Depending on the application, you may be dealing with NFPA 70 Article 702 for optional standby systems or Article 700 for emergency systems, and NFPA 110 if it's a life-safety application. Stationary engine installation falls under NFPA 37. Emissions certification matters too — some state and local air districts have requirements beyond federal EPA rules, and that can eliminate certain configurations entirely. Verify current regulations with the authority having jurisdiction before you quote.

What I'd do differently

Three things.

First, I'd get the fuel question answered before the pricing question. Fuel type drives installation scope, which drives the only number the end customer actually cares about.

Second, I'd stop treating a delivery window as a soft promise. When a deadline is already sold downstream, the certainty of delivery is worth paying for — not because faster is better, but because "probably on time" is the most expensive phrase in procurement. A $14,000 price advantage disappears the moment you're issuing credits and losing a dealer's trust.

And third, I'd write allocation language into the purchase order itself. If a supplier can't commit to a date, that's not a lead time. That's a red flag.

We still buy from both channels. Channel A wasn't a bad actor — they just weren't built for a deadline. Channel B now gets first look at every time-sensitive order, and I budget the premium instead of hoping I won't need it.

Pricing ranges are for general reference only and reflect quotes collected in Q4 2024. Actual pricing varies by vendor, configuration, volume tier, and time of order. Regulatory and code references are for general guidance — consult the current code editions and your local authority having jurisdiction.