Updated August 2026 · Portlandia Electric Supply

I've sold Briggs & Stratton generators to homeowners, farmers, and data-center contractors for fifteen years. The brand occupies a specific niche: not the cheapest portable on the shelf, not the premium price of a Kohler or Generac standby, but a workhorse middle ground with parts availability that outlasts most of the competition. When a farmer in eastern Oregon calls me at 6 p.m. because his well pump quit during a ice storm, the part he needs is usually in stock at a local dealer — and that's worth more than a 2% efficiency gain on a spec sheet. This guide covers the full Briggs & Stratton lineup: portable, home standby, and commercial, with the load math, fuel data, and NEC code references you need to install them right.

Briggs & Stratton Power Products Group manufactures three generator categories: portable generators (1,000W to 17,500W), home standby generators (8kW to 26kW), and commercial/industrial units (up to 200kW under the SimpliPHI and commercial lines, though the core B&S brand tops out around 26kW for residential standby). Most of our volume at Portlandia Electric Supply is in the standby range — 10kW to 26kW — where the brand competes head-to-head with Generac and Champion.

The residential standby lineup uses either air-cooled or liquid-cooled engines. Air-cooled units (8–26kW) run on natural gas or propane and use a V-twin OHV engine. Liquid-cooled units (35–60kW, commercial) use a Ford or GM engine block and are a different product entirely. For 90% of residential jobs, the air-cooled line is what you'll quote.

Model	kW (NG/LPG)	Engine	Transfer Switch	Enclosure	Sound Level (dB)	Typical Price
040638 (8kW)	8 / 9	V-twin 420cc	100A SE	Aluminum	66	$2,899
040639 (10kW)	10 / 11	V-twin 420cc	100A SE	Aluminum	66	$3,199
040640 (12kW)	12 / 13.5	V-twin 627cc	200A SE	Aluminum	67	$3,599
040641 (15kW)	15 / 17	V-twin 627cc	200A SE	Aluminum	67	$4,199
040642 (17kW)	17 / 19	V-twin 816cc	200A SE	Aluminum	68	$4,799
040643 (20kW)	20 / 22	V-twin 816cc	200A SE	Aluminum	68	$5,299
040644 (26kW)	26 / 29	V-twin 999cc	200A SE	Aluminum	69	$6,299

Source: Briggs & Stratton dealer price sheet, Q3 2026. Prices are generator only; transfer switch and installation extra. NG = natural gas, LPG = propane.

The "SE" transfer switch is Briggs & Stratton's Smart Energy management switch. It sheds non-essential loads (second AC, pool pump, electric dryer) when total demand exceeds generator capacity, then restores them when capacity frees up. This matters: a 20kW generator with load management can cover a 3,500 sq ft home with two AC units. Without load management, that same home needs 26kW.

NEC Article 220 and Article 445 govern generator sizing. For a whole-house standby unit, the simplest compliant method is the "optional standby calculation" under 220.87: measure actual demand over a year, or calculate connected load with demand factors. In practice, most residential installers use a load survey: list every appliance, apply NEC demand factors, and size to 80% of generator capacity for continuous loads.

Here's a real load calc I ran last month for a 3,200 sq ft home in Bend, Oregon:

Load	Running Watts	Starting Watts	NEC Demand Factor	Calculated Load
Central AC (4 ton)	4,000W	7,800W	100%	4,000W
Heat pump backup	5,000W	5,000W	100%	5,000W
Well pump (1 HP)	2,000W	4,000W	100%	2,000W
Refrigerator	700W	2,200W	100%	700W
Freezer	500W	1,500W	100%	500W
Sump pump (1/2 HP)	1,050W	2,150W	100%	1,050W
Lighting & outlets (general)	3,000W	—	65%	1,950W
Electric water heater	4,500W	4,500W	0% (load shed)	0W
Total calculated load				15,200W

The continuous load is 15,200W. NEC 445.13 requires generators to be sized at 115% of continuous load for non-automatically started units, or at 100% for automatic standby with load management. With a Smart Energy switch shedding the water heater, this home fits comfortably on a 20kW Briggs & Stratton (20,000W rated, 80% continuous = 16,000W available). Without load management, the same home needs 26kW to cover the water heater plus margin.

One thing I've learned the hard way: always check the locked-rotor amperage (LRA) on the AC compressor nameplate. A 4-ton unit with a 120 LRA compressor draws 7,200W at startup. If the generator can't supply that inrush, the compressor stalls and burns. Briggs & Stratton publishes a "motor starting" rating — typically 2.5× running watts — but I verify against the specific LRA every time.

Briggs & Stratton standby generators are dual-fuel: they ship configured for natural gas but can be field-converted to propane with a jet change. The fuel consumption difference is significant. Natural gas has less energy per cubic foot than propane (about 1,040 BTU/ft³ for NG vs. 2,516 BTU/ft³ for LPG at 60°F), so a generator burns more NG volume to produce the same kW.

Generator Size	NG @ 50% Load (ft³/hr)	NG @ 100% Load (ft³/hr)	LPG @ 50% Load (gal/hr)	LPG @ 100% Load (gal/hr)
10kW	101	180	1.13	2.08
12kW	116	210	1.29	2.42
15kW	142	260	1.58	3.00
20kW	188	348	2.08	4.00
26kW	242	453	2.67	5.21

Source: Briggs & Stratton fuel consumption tables, based on standard conditions (NG at 1,040 BTU/ft³, LPG at 2,516 BTU/ft³).

For a propane installation, size the tank for the longest expected outage. A 20kW generator at 50% load burns 2.08 gal/hr. A 5-day outage (120 hours) needs 250 gallons. Add 20% for cold-weather vaporization loss and tank depletion safety margin, and you need a 500-gallon tank minimum. A 1,000-gallon tank is standard for whole-house standby in rural areas.

Natural gas installations are simpler — no tank, no refueling — but they depend on utility pipeline pressure. Briggs & Stratton requires 5–7 inches water column at the generator inlet. I always install a dedicated gas meter and regulator, sized to the generator's full-load demand plus the home's existing load. A 20kW unit at 348 ft³/hr needs a 1-inch gas line at 20 feet, or 1¼-inch at 50 feet, per NFPA 54.

I've been on enough job sites with failed inspections to know the common trip points. Here's the checklist our electricians run before calling the inspector:

Transfer switch location (NEC 702.12): The transfer switch must be readily accessible. In a basement behind a water heater is not readily accessible. We mount at eye level, within 10 feet of the service panel, with 36 inches of clear working space per NEC 110.26.

Generator grounding (NEC 250.34): Portable generators under 15kW used for standby via a transfer switch must be grounded with an electrode if the neutral is bonded. Standby generators with a permanently installed neutral-to-ground bond at the generator need their own grounding electrode. We drive an 8-foot ground rod within 5 feet of the generator and bond with #6 AWG copper.

Disconnecting means (NEC 445.18): A generator must have a disconnecting means within sight. For standby units, the breaker on the generator itself satisfies this if the generator is outdoors. If installed in an outbuilding, a separate disconnect is required at the building entrance.

Fuel shutoff (NEC 445.19): A remote fuel shutoff is not required by NEC for generators under 600V, but the fire marshal may require one. We install a quarter-turn gas ball valve at the house exterior, labeled "GENERATOR FUEL SHUTOFF," on every job.

Clearance to combustibles: Briggs & Stratton specifies 18 inches from walls, 5 feet from windows and doors, and 3 feet from any combustible overhang. The exhaust points away from the house. I measure these with a tape measure — eyeballing it costs callbacks.

A standby generator that doesn't start during an outage is worse than no generator at all — it's a false sense of security. Briggs & Stratton recommends the following maintenance intervals, and our field data says following them closely cuts no-start incidents by 80%.

Interval	Task	Parts Needed	Estimated Cost
Weekly	Exercise cycle (auto-run, 12 min)	—	$0
Monthly	Visual inspection: leaks, corrosion, pests	—	$0
Every 6 months / 100 hrs	Oil change, filter check, spark plug inspect	SAE 30W oil, filter, plug	$45
Annually / 200 hrs	Full service: oil, filter, plug, air filter, battery test, valve clearance check	Full service kit	$120
Every 2 years	Coolant flush (liquid-cooled only)	Coolant	$80
Every 3 years	Battery replacement	Group 26R battery	$85

The exercise cycle is critical. Briggs & Stratton units self-test weekly, but if the homeowner cancels the exercise because "it's loud," the battery drains, fuel gums, and seals dry out. We set the exercise for Tuesday at 2 p.m. — midweek, midafternoon, when the homeowner is at work and neighbors are less likely to complain.

For cold climates, we install a cold-weather kit: battery warmer (maintains battery above 40°F), oil heater (keeps oil viscosity in range), and breather heater (prevents icing). The kit costs $189 and is non-negotiable below 20°F design temperature. A frozen battery won't crank a 999cc engine.

A standby generator is a 15- to 20-year asset. The purchase price is only part of the story. Here's the 10-year cost breakdown for a 20kW Briggs & Stratton with automatic transfer switch, installed in the Portland metro area:

Cost Category	Year 1	Years 2–10 (annual avg)	10-Year Total
Generator + transfer switch	$5,299	—	$5,299
Installation (electrical + gas)	$3,500	—	$3,500
Permits & inspection	$450	—	$450
Annual maintenance	$120	$120	$1,200
Propane (50 hrs/yr @ 50% load)	$312	$312	$3,120
Battery (every 3 years)	—	$28	$255
Repairs / warranty claims	—	$75	$675
Total	$9,681	$535	$14,499

Propane at $3.00/gal, maintenance at dealer rates, 50 hours annual runtime (typical for Pacific Northwest outage pattern).

Compare this to the cost of a multi-day outage: hotel ($150/night), spoiled food ($300), frozen pipes ($2,000+), lost work. For a home with a well pump, medical equipment, or a home office, the generator pays for itself in one extended outage. Our data from customers who experienced the 2021 ice storm in Oregon shows an average avoided loss of $4,200 per household with standby power.

We stock Briggs & Stratton, Generac, Kohler, and Cummins. Here's how I route customers:

Briggs & Stratton: Best value for standard residential loads. Parts everywhere. Smart Energy switch is genuinely useful. Warranty is 6 years parts, 3 years labor — shorter than Generac's 5-year comprehensive, but the parts network is denser.

Generac: More models, better mobile app (Guardian monitoring), longer standard warranty. Costs 10–15% more for equivalent kW. If the customer wants Wi-Fi monitoring and a sleek enclosure, Generac wins.

Kohler: Premium build quality, liquid-cooled options at lower kW, best sound attenuation. Costs 30–40% more. We sell Kohler to customers who will pay for quiet and longevity.

Cummins: Commercial and industrial focus. Overkill for residential. We spec Cummins for farms, data centers, and municipal buildings.

My honest take: for a typical 2,500 sq ft home with a gas furnace and one AC unit, the Briggs & Stratton 15kW or 20kW with Smart Energy is the right tool. It's not the cheapest, not the most expensive, but it's the one I can get parts for on a Sunday.

Step 1: Site the generator per NEC clearances. Place the generator on a level concrete pad, 18 inches from walls, 5 feet from doors and windows, with exhaust pointing away from the house. Maintain 36 inches of working space per NEC 110.26.

Step 2: Install the transfer switch next to the service panel. Mount the automatic transfer switch within 10 feet of the main panel at eye level. Run conduit between the panel and switch. Bond the neutral per the manufacturer's wiring diagram.

Step 3: Connect the fuel supply. For natural gas, run a dedicated line from the meter with properly sized pipe per NFPA 54. For propane, install a regulator at the tank and run copper or CSST to the generator. Install an exterior shutoff valve.

Step 4: Wire the generator output to the transfer switch. Run appropriately sized conductors from the generator output breaker to the transfer switch input lugs. Size per NEC 445.13 and 310.16. Use THHN/THWN-2 in conduit.

Step 5: Ground the system. Drive an 8-foot ground rod within 5 feet of the generator. Bond the generator frame to the rod with #6 AWG copper. Connect the generator ground to the transfer switch ground bus and the existing grounding electrode system.

Step 6: Program the exercise cycle and test. Set the weekly exercise time via the control panel. Force a transfer test by opening the main breaker. Verify all essential loads transfer correctly and the generator carries load without overload faults.

Ready to spec a Briggs & Stratton generator? Browse our generator catalog or call our design desk for load calculations and bulk pricing. We stock the full residential standby line with same-week availability from Portland.

Related reading: Briggs & Stratton brand guide, Generac brand guide, Kohler brand guide, Cummins brand guide, Whole-house generator guide, Generator protection guide, Liquid-cooled generators, 13kW generator guide, 18kW generator guide, Standby generator buyer's guide, Battery backup runtime calculator, Standby generator investment guide, Furnace electrical guide, AC condenser electrical guide.