By Jennifer Kirstens · August 31, 2026 · 26 min read

Contractors and installers spec standby generators the way physicians write prescriptions: the brand and the size have to match the job, not the marketing. PES Supply is set up around that reality. We are an authorized online distributor for the four brands that own the U.S. standby market — Generac, Cummins, Briggs & Stratton, and Kohler — with 1,385 SKUs on the shelf between them and a distribution center in Louisville, Kentucky that ships pallet-quantity orders to installer accounts every business day.

This page is the top of a hub. It exists to answer four questions in one place: which brand fits which job, how PES prices and freights those brands to contractor accounts, how the fuel and transfer-switch decisions cascade, and how to open an account so you can quote your next residential or commercial standby job at real distributor cost. Every claim below links to the deeper brand-specific pages or the interactive sizing calculator. Bookmark it — it is meant to be a working reference, not a marketing sheet.

The phrase 'authorized distributor' gets thrown around loosely on the open web. In OEM contract language it means something specific: the OEM has granted the reseller a signed distribution agreement, the OEM enforces list pricing tiers, warranty registration flows through the OEM's dealer portal, and returns/repairs route through the OEM's parts network rather than a third-party grey channel. That matters to a contractor for exactly three reasons.

First, warranty. A Generac Guardian sold through an unauthorized channel does not carry the 5-year standby warranty out of the box — it carries whatever the reseller wrote into its own T&Cs, which is usually nothing. Authorized channel means the serial number is registered against the end-user address and the homeowner's warranty follows the unit for its full term, including labor coverage in the first two years for most Generac Guardian models. The same rule applies at Kohler (5-year residential standby), at Cummins (5-year on Quiet Connect QC-series), and at Briggs & Stratton (5-year on Fortress and residential air-cooled).

Second, real-time inventory. Authorized distributors are fed inventory feeds from the OEM. When Generac's Trenton, South Carolina plant releases a batch of 7291 26 kW Guardians, that batch shows up on our warehouse feed the day it ships, not three weeks later after the greymarket brokers stop bidding on it. That means a contractor who quotes a 26 kW Guardian for a Thursday install is not gambling on backorder purgatory.

Third, parts. The moment a standby generator is installed, it starts consuming parts — air filters, oil filters, spark plugs on air-cooled, coolant on liquid-cooled, and, at year 5–7, control-board revisions. Authorized distributors stock OEM part numbers with OEM traceability; grey-market resellers stock 'compatible' aftermarket parts that fail warranty audit. PES ships OEM parts under the same freight terms as the units.

The comparison table below is the fastest way to see how the four brands stack up on the dimensions that decide most contractor jobs: how deep the lineup runs, where the air-cooled/liquid-cooled crossover sits, and what standby coverage looks like.

The dimensions that don't fit in a table matter too. Generac dominates the residential standby market — roughly 3 out of 4 whole-home standby installs in the United States are Generac Guardians. That share plus the tightest air-cooled model spacing (18, 20, 22, 24, 26 kW) is why PES stocks 849 Generac SKUs against 85 Kohler SKUs. Cummins owns the commercial diesel end — Quiet Connect for residential, but the C-series (25–200 kW) is where hospitals, telco huts, and small industrial jobs live. Briggs & Stratton's Fortress line is the sleeper — 30 to 125 kW liquid-cooled at a lower price ceiling than Kohler REZG, which makes it the value pick for light-commercial jobs where Cummins is overkill. Kohler is the premium residential pick and, at the commercial end, the go-to when the specifier wants a name that reads well in a hospital board packet.

The deep-dive pages break each brand's lineup out with real kW spacing, fuel maps, transfer-switch pairings, warranty terms, and application matrices:

• Generac Standby Generator Authorized Distributor — Contractor Pricing
• Cummins Standby Generator Authorized Distributor — Contractor Pricing
• Briggs & Stratton Standby Generator Authorized Distributor — Contractor Pricing
• Kohler Standby Generator Authorized Distributor — Contractor Pricing

Contractors quoting standby generator jobs today have three online distributor options: generator specialists like Norwall.com, generalist electrical wholesalers like a Rexel or Graybar branch, or a dedicated OEM-authorized distributor like PES. The three channels look similar on the landing page. They diverge sharply on the four things that actually matter to a contractor: OEM-authorized status, inventory depth across brands, contractor pricing structure, and freight economics.

The consequential difference for contractors is the four-brand OEM-authorized status. Most generator specialists have one or two brand relationships they lean on heavily and cover the others via secondary channels. That is fine if the customer wants the specialist's primary brand. It's a problem the moment a homeowner or GC asks for the specific brand the specialist doesn't have a direct line on — the contractor either walks the customer away from the preferred brand or absorbs a longer lead time and thinner margin. PES's OEM-authorized status across all four brands means the contractor's spec drives the quote, not the distributor's cheapest inventory line.

Retail buyers pay list. Contractor accounts do not. The way our pricing tiers work is straightforward: PES buys direct from each OEM at the OEM's distributor cost, and passes that structure through in three published tiers. Tier 1 is the standard installer account — open with a valid electrical or general-contractor license and an EIN. Tier 2 kicks in at $50,000/year in cumulative purchase volume across brands. Tier 3 activates at $200,000/year and layers freight rebates on top of the unit discounts.

Pallet-quantity buys — typically 4–6 air-cooled units on a single 48×40 pallet, or one liquid-cooled 30–48 kW skid — layer additional freight economics on top of the tier discount. That is where the numbers really move on a multi-unit residential development or a chain-retail rollout. Ask the account rep for a pallet quote rather than a per-unit quote and the number will come back lower.

Project quotes work differently. When a contractor sends a bill of materials for a single job that crosses $25,000 in generator + transfer switch + parts, PES prices the project as a bundle rather than as a sum of line items. That bundle price is usually 3–6% below the tier price on the same line items, because we can plan the freight consolidation and warranty registration as a batch.

Fuel choice determines both continuous kW output and long-term operating cost. All four brands offer LP/NG dual-fuel on the air-cooled residential lines. Diesel is exclusive to the commercial liquid-cooled lines (Cummins C-series, Generac Protector Diesel, Kohler REOZJ/REOZK diesel, Briggs Fortress diesel). Bi-fuel and tri-fuel become options in the commercial space — Cummins in particular offers factory tri-fuel on parts of the C-series.

Standby generators fall into three application classes that determine the entire spec — kW, fuel, transfer switch, warranty terms, and pad prep. Get the class right first, and the model number falls out of the calculator.

A whole-home 5,000 sq ft residence in Louisville is a 22–26 kW air-cooled job — the specifier has to decide between Generac 7291 (26 kW/LP with 200A SE ATS), Kohler 26RESV, Briggs 040679 (26 kW), or Cummins RA22 depending on the fuel available and the customer's warranty preferences. A 12,000 sq ft veterinary clinic with imaging equipment is a 48–60 kW liquid-cooled job — that's Generac Protector RG04854, Kohler 48REZG, Briggs Fortress 45 kW, or Cummins C60 D5. A cellular tower site in rural Kentucky running as prime power on diesel is a Cummins C80 D6 or Kohler 80REOZJ, sized against a 24×7 duty cycle rather than an outage-triggered one.

Every unit larger than a 14 kW air-cooled ships as freight, not parcel. PES ships from Louisville, Kentucky (1507 Portland Ave) with published freight to every ZIP code in the lower 48. Contractors can pick from three freight modes on any order:

The drop-ship-direct option is the least-known and most useful for contractors doing residential development work. When a builder orders 12 identical 22 kW Guardians for a new 12-lot subdivision, PES can arrange for Generac's Trenton, SC plant to ship directly to the job site or the contractor's yard, on a single consolidated freight bill. That saves the handling markup and often cuts 5–7 days off delivery.

Every one of the four brands lists a 5-year standby warranty on the residential air-cooled line. In the fine print, those terms are not identical. Contractors quoting jobs need to know where the coverage differs so the customer doesn't call four years in with an expensive control-board failure and find out labor isn't covered. Here's the substantive comparison:

The labor-coverage distinction is the one that matters most on residential jobs. A Cummins Quiet Connect that fails in year 3 is a parts-only warranty claim — the homeowner or contractor eats the service call and labor. The same failure at year 3 on a Generac Guardian, Kohler RESV, or Briggs air-cooled is still parts-only under the standard warranty, but if the failure happened in year 1 or 2, the OEM covers labor as well. Extended service agreements are available on all four brands and PES bundles them with the initial invoice on request.

The four brands share very similar physical footprints in the residential air-cooled class — all four fit inside a 48″ × 25″ × 29″ envelope for 22 kW and larger units. Where they diverge is on clearance and required pad prep. Contractors doing a lot of standby jobs learn to walk the site with these numbers memorized:

NG meter capacity is the trap on 24 and 26 kW residential jobs. A typical 1980s–1990s residential NG meter caps out around 250 CFH — fine for a 16 kW generator, undersized for a 22–26 kW at full load. When the meter capacity is on the edge, either upsize the meter with the utility (permit + appointment, typically 4–8 weeks) or drop the sizing to a 20 kW unit and add load management to cover the peak. Both fixes work; the wrong fix is to install and hope.

Opening an account with PES Supply takes about a day. The steps are short and the paperwork is what you already have on file for any wholesaler.

The fastest way to size a Generac, Cummins, Briggs & Stratton, or Kohler standby generator against a real residential or commercial spec is the interactive calculator on our contractor portal. Enter total load, primary appliances, and fuel preference — get a recommended kW, brand options across all four lines, transfer switch amperage, fuel line size, and pad size in one screen. Free with contractor account registration.

• Complete Guide to 26 kW Generators (Generac 7291 + alternatives)
• Generator Fuel Consumption Chart — LP / NG / Diesel by kW
• Generator Load Reference Chart — Whole-Home Watts by Circuit
• Generator Collection — All 1,385 SKUs