By Jennifer Kirstens · August 31, 2026 · 20 min read

PES Supply is an authorized online distributor for Generac standby generators. This page is the working reference for contractors and installers who quote Generac residential and commercial standby jobs and want distributor-tier pricing, real inventory, and OEM parts backing. We stock 849 Generac SKUs at our Louisville, Kentucky distribution center — from air-cooled residential 7.5–26 kW through liquid-cooled commercial 30–150 kW — and ship to installer accounts every business day.

Generac is the U.S. standby generator category leader — roughly three out of four whole-home standby installs in the country are Generac Guardians. The lineup runs from 7.5 kW residential entry points all the way to 150 kW commercial industrial, with the tightest kW-spacing of any manufacturer: 18, 20, 22, 24, 26 kW air-cooled Guardians, then 30, 36, 48, 60, 80, 100, 125, 150 kW Protector and Industrial liquid-cooled. That spacing is why Generac wins so many jobs — the model number always lands close to the sizing math without headroom waste. It is also why we stock 849 Generac SKUs against 85 Kohler and 189 Cummins.

Generac's lineup breaks into three families. Guardian is the residential air-cooled line (7.5–26 kW), Protector is the light-commercial liquid-cooled line (30–48 kW), and Industrial is the heavy commercial line (60–150 kW). Each family has LP/NG dual-fuel and, above 30 kW, diesel and bi-fuel options. Pricing tiers below are indicative of Tier-1 contractor pricing — pallet quotes and project bundles run 4–7% lower.

The 22 kW (7043) and 26 kW (7291) Guardians are the volume sellers on the residential side — together they cover the vast majority of 2,500–5,000 sq ft whole-home jobs. On the commercial side, the Protector 48 kW and Industrial 80/100 kW are our highest-turn SKUs. Full 26 kW breakdown is on our complete 26 kW generator guide.

Standby generator demand in the United States has grown roughly 10–14% per year for the past decade, driven by an aging grid, longer average outage durations, and the electrification of heating (heat pumps) and transportation (EV chargers) that widens the gap between grid-outage impact and homeowner tolerance for it. Inside that growing market, each of the four major brands has a defensible position that contractors should recognize before they quote a job.

Generac's share is concentrated where its structural advantages line up with customer priorities. On residential jobs, that means the customer profile, the fuel available, and the willingness to pay a premium (or press for a discount) tilt each spec toward one brand over another. On commercial jobs, the tilt is mostly about who the specifier is and what reads well on their procurement committee's spec sheet.

Every Generac residential Guardian ships LP/NG dual-fuel — the installer sets the fuel type at commissioning by adjusting a regulator jumper. That flexibility is a real advantage on jobs where the customer might convert from LP to NG later. Transfer switches pair to the ATS ladder shown below; the service-entrance versions of the 100A and 200A ATS are the two most common on residential.

Load management modules (Generac Smart Management Modules, or SMMs) let a smaller unit cover a bigger house by shedding the AC compressor when the electric dryer kicks in — that's how a 22 kW covers a 4,000 sq ft home that raw math says needs 26 kW. SMMs are stocked as part numbers 6199 and 6198 at PES.

Generac's residential dominance means the Guardian air-cooled line is what most contractors will spec 80% of the time. The Protector 30–48 kW is the natural next step when the load math crosses the 26 kW residential ceiling — the Protector RG03015 (30 kW) is essentially a liquid-cooled 26 kW upgrade for the same physical envelope.

Generac's residential Guardian standby warranty is 5 years / 2,000 hours, whichever comes first. Years 1–2 include labor coverage in most Generac Guardian air-cooled models (verify per model). Protector liquid-cooled units carry a 5-year limited standby warranty. Industrial units carry 2 years unlimited / 5 years standby on the engine, alternator, and control panel. Every unit sold through PES is warranty-registered against the end-user address through Generac's dealer portal at invoice.

Generac's residential grip is unmatched, but the four-brand comparison shows where each brand's strengths lie. Kohler is the premium residential pick, Cummins is the diesel-heavy commercial pick, and Briggs & Stratton Fortress is the value pick on light-commercial liquid-cooled. Feature matrix:

Every standby generator becomes a parts customer the day it's commissioned. Air-cooled units consume oil filters, air filters, spark plugs, and batteries; liquid-cooled units consume the same list plus coolant, coolant hoses, and the occasional control-board revision. PES stocks the OEM part numbers under the same freight terms as the units — same tier discounts, same next-business-day shipping from Louisville. Serial-traceable part numbers pass Generac warranty audit; grey-market 'compatible' aftermarket parts do not.

On multi-unit residential installer accounts, PES bundles a starter parts kit with the initial generator purchase order — filters, spark plugs, and oil for the first three annual services on each unit. That single line item saves the installer the pain of re-ordering three months later when the first service call comes due.

These seven steps are the sequence PES account reps walk through with contractors when a new job comes in. Follow them and the quote comes out tight the first time.

Standby generators do not fail from age. They fail from missed service. Every one of the four brands specifies an annual service that keeps the warranty in force and the unit ready to start on the first outage of the year. Generac residential air-cooled service is roughly the same across the lineup: change the oil and filter, check air filter, replace the spark plugs at year 2 and every 2 years after, load-test the battery, exercise the unit under full load, and inspect the enclosure and gas line. Liquid-cooled commercial units add coolant checks, coolant additive replenishment, and belt/hose inspection.

PES bundles the annual service kit as a stocked SKU so the installer's service tech shows up with everything on the truck. On multi-unit installer accounts, PES ships service kits on an annual cadence tied to install anniversary dates — the installer's back office doesn't have to re-order per-unit.

• Standby Generator Distributor Hub — All 4 Brands
• Contractor Portal Generator Sizing Calculator (free w/ registration)
• Generator Load Reference Chart
• Generator Fuel Consumption Chart
• Generac Generator Collection
• Cummins Standby Generator Authorized Distributor
• Briggs & Stratton Standby Generator Authorized Distributor
• Kohler Standby Generator Authorized Distributor