26 kW generator
One 26 kW standby generator is the Generac Guardian 26 kW. It puts out 26,000 W on propane, while natural gas output is about 23,140 W. Other models rate a little differently. With 3-ton central air, natural gas coverage reaches houses up to 5,000 sq ft.
With natural gas, an installed 26 kW unit starts at $11,119 in Arkansas, while Oregon comes to $13,419. Labor costs by state, drawn from BLS wages for May 2025.
Will 26 kW be enough for your house? Size it with three questions, counting the AC start or the well pump start.
What a 26 kW generator runs
| Loads running together | Running | Peak at a motor start | Natural gas | Propane |
|---|---|---|---|---|
| Essentials | 4.5 kW | 5.6 kW | runs | runs |
| Essentials and a 1 hp well pump | 6.5 kW | 8.5 kW | runs | runs |
| Essentials and a 2-ton central AC | 7.0 kW | 9.0 kW | runs | runs |
| Essentials and a 3-ton central AC | 8.0 kW | 10.5 kW | runs | runs |
| Essentials and a 4-ton central AC | 9.5 kW | 12.5 kW | runs | runs |
The essentials list covers a microwave, a fridge, lights, a 1/2 hp sump pump, TV, a freezer, a router and the furnace blower. That "runs" figure keeps your running load under 80% of the rating, and the biggest motor start is covered on top of it.
| Whole house load | Natural gas or propane |
|---|---|
| No central air | up to 5,000 sq ft |
| Central AC, 3 ton | up to 5,000 sq ft |
| Central AC, 4 ton | up to 5,000 sq ft |
The whole house rows use NEC 220.83. Lights and outlets take 3 VA for each sq ft, and kitchen and laundry circuits plus gas heat are included, while an electric range, a dryer and a water heater are not. Check your own house.
Hourly fuel use
| Load | Natural gas | Gas cost | Propane | Propane cost |
|---|---|---|---|---|
| 25% | 116 cu ft | $2.53 | 1.28 gal | $3.48 |
| 50% | 188 cu ft | $4.12 | 2.06 gal | $5.62 |
| 75% | 261 cu ft | $5.71 | 2.84 gal | $7.77 |
| 100% | 333 cu ft | $7.30 | 3.63 gal | $9.91 |
Half load and full load come from the Guardian 26 figures in Generac's fuel table, and 25% and 75% read between them. Costs are based on EIA US average prices.
Hours per propane tank
| Tank | 25% load | 50% load | Full load |
|---|---|---|---|
| 120 gal | 75 h | 47 h | 26 h |
| 250 gal | 157 h | 97 h | 55 h |
| 500 gal | 314 h | 194 h | 110 h |
| 1,000 gal | 627 h | 388 h | 220 h |
A tank's fill level reaches 80%.
What installation costs
| Line, 26 kW | Natural gas | Propane | Basis |
|---|---|---|---|
| Generator and transfer switch | $8,219 | $8,219 | Generac list price |
| Electrician: switch, wiring, start-up | $3,000 to $5,500 | $3,000 to $5,500 | published install ranges, set at an hourly US average wage of $34.37 (BLS) |
| Fuel line | $500 to $2,000 | $800 to $2,500 | gas line runs from the meter; propane line runs from the tank |
| Pad and permit | $300 to $1,200 | $300 to $1,200 | composite pad or slab, local fees |
| Installed | $12,019 to $16,919 | $12,319 to $17,419 | propane leaves out the tank |
Costs for whole house generators by state.
26 kW compared with other brands
| Brand | Model at 26 kW or next up | List price | Installed, natural gas | Page |
|---|---|---|---|---|
 Generac | Guardian 26 kW, with switch | $8,219 | $12,019 to $16,919 | Generac cost |
 Kohler | 26 kW 26RCA, with switch | $7,546 | $11,346 to $16,246 | Kohler cost |
Each unit's installed price includes the same four items: the permit, the pad, the gas line and the electrician. Generac's price for a switch in the nearest size is added as well when a unit is sold without one. Generac and Kohler's list prices come straight from their own pages. Dealers handle the Cummins, Briggs & Stratton and Champion brands, and each dealer quotes the price of that unit: Cummins generator prices, Briggs & Stratton generator prices, Champion generator prices.