Kohler Generator Sizing Guide — Which RESAL Do I Need?
The definitive guide to sizing a Kohler RESAL standby generator — with the complete model lineup, Kohler vs Generac head-to-head, square-footage sizing tables, and installed cost estimates for every model.
Quick Answer
For most homes (1,500–2,200 sq ft) with gas appliances and 2–3 ton AC, the Kohler 14RESAL is the right size. Smaller homes under 1,200 sq ft: 10RESAL. Larger homes or all-electric appliances: 20RESAL. Kohler generators are quieter and require less maintenance than Generac — oil changes every 200 hours vs 100.
Key Takeaways
- The Kohler 14RESAL is the best choice for most 1,500–2,200 sq ft homes — quieter and lower-maintenance than comparable Generac units.
- Kohler's 200-hour oil change interval means roughly half the annual service calls vs. Generac's 100-hour interval.
- Kohler generators are only sold through authorized dealers — not Home Depot or Amazon. Smaller dealer network than Generac.
- Cast-iron cylinder sleeves give Kohler engines better long-term durability than aluminum-bore alternatives.
- Kohler's 5-year / 2,000-hour warranty exceeds Generac's 5-year / 1,500-hour coverage on equivalent models.
Kohler Generator Sizing Chart — Complete RESAL Lineup
All models run on natural gas or LP propane. Installed cost includes the Kohler RXT transfer switch, electrical work, gas line, concrete pad, and permits.
Small home, gas appliances only, no central AC
Cannot support central AC — essentials only
Small home with gas appliances and 1.5-ton central AC
Entry-level RESAL — limited AC support
Medium home with gas appliances and 2–3 ton central AC
Most popular residential RESAL
Larger home, all-electric appliances, 3.5-ton AC
Best fit for all-electric homes
Large home, 4-ton+ AC, EV charging, all-electric
Air-cooled; covers virtually any residential load
Estate-size homes, light commercial, critical facilities
Liquid-cooled — extended runtime duty cycle
Prices are approximate MSRPs as of 2025. Installed costs vary by region — get quotes from Kohler-authorized dealers at power.kohler.com.
Kohler RESAL Size by Home Square Footage
Gas appliances = gas furnace, gas range, gas water heater. All-electric = electric everything including heat pump or electric furnace.
| Home Size | Gas Appliances | All-Electric |
|---|---|---|
| Under 1,000 sq ft | 8.5RESL | 10RESAL |
| 1,000–1,500 sq ft | 10RESAL | 14RESAL |
| 1,500–2,000 sq ft | 14RESALMost Popular | 14RESAL |
| 2,000–2,500 sq ft | 14RESAL | 20RESAL |
| 2,500–3,500 sq ft | 20RESAL | 26RCL |
| 3,500–5,000 sq ft | 26RCL | 38RCLC |
| 5,000+ sq ft | 38RCLC+ | 38RCLC+ |
What Sets Kohler Apart
Cast-Iron Cylinder Sleeves
Kohler's RESAL engines use cast-iron cylinder sleeves rather than aluminum bores. Cast iron is significantly more wear-resistant, extending engine life well beyond the 2,000-hour warranty threshold. This is a manufacturing choice that adds cost but pays back over a 20–30 year generator lifespan.
200-Hour Oil Change Interval
Kohler's RESAL generators go 200 hours between oil changes — twice as long as Generac's 100-hour interval. Over a 20-year life with 100 hours of annual operation, this means 10 oil changes vs. 20 for a Generac. At $150–$350 per service call, Kohler's longer interval saves $1,500–$3,500 in lifetime maintenance costs.
Quieter by Design
Kohler RESAL models operate at 63–67 dBA at 23 feet — measurably quieter than comparable Generac models (65–70 dBA). The aluminum housing, precision-balanced engine, and acoustic treatment combine to make the Kohler noticeably quieter during nighttime operation when noise matters most.
100 Years of Engine Manufacturing
Kohler has manufactured engines since 1920 — over 100 years of continuous production. Every RESAL generator uses a Kohler-built engine (not outsourced), and Kohler's industrial engine heritage includes commercial power plants, marine generators, and heavy equipment. This depth of manufacturing experience informs every residential unit.
Kohler vs Generac — Head-to-Head
Comparing equivalent 14kW residential standby models side by side.
| Factor | Kohler 14RESAL | Generac Guardian 14kW |
|---|---|---|
| Noise level (at 23 ft) | ✓63–67 dBA | 65–70 dBA |
| Oil change interval | ✓200 hours | 100 hours |
| Engine construction | ✓Cast-iron sleeves | Aluminum bore |
| Warranty | ✓5 yr / 2,000 hr | 5 yr / 1,500 hr |
| Unit MSRP (14 kW) | ✓$4,199 | $4,499 |
| Dealer network (US) | Smaller | ✓Largest in US |
| Smart monitoring app | OnCue Plus | Mobile Link |
| Product range | Focused lineup | ✓Widest selection |
| DIY availability | Dealer-only | ✓Home Depot / online |
| Industrial heritage | ✓Since 1920 | Since 1959 |
| Annual service cost | $200–$400 | $150–$400 |
Bottom line: Kohler wins on engineering quality — quieter, longer service intervals, better engine materials, stronger warranty. Generac wins on ecosystem — larger dealer network, easier purchasing, lower installed cost in most markets. For most homeowners, Generac's practical advantages outweigh Kohler's engineering edge. But for homeowners who will keep the generator for 20+ years and want minimum maintenance hassle, Kohler's lifetime cost of ownership is lower despite the higher upfront price.
How to Size a Kohler Generator for Your Home — 5 Steps
Calculate your total wattage using our calculator
Add every appliance you need to run during an outage. The calculator returns running watts and surge watts. Your Kohler generator must exceed the surge watts figure with at least 20% headroom.
Match your wattage to the Kohler model lineup
Divide your running watts by 0.80 to get the minimum recommended kW. Find the Kohler RESAL model at or above that number: under 7kW → 10RESAL; 7–11kW → 14RESAL; 11–16kW → 20RESAL; 16–21kW → 26RCL.
Confirm your fuel supply
All RESAL models run on natural gas or LP. If you have natural gas service, confirm adequate gas line pressure (minimum 5–7 inches water column at the generator). For LP, plan for a 100–500 gallon dedicated tank.
Find a Kohler-authorized dealer
Kohler generators are sold and installed exclusively through authorized dealers — not big-box retailers. Use the Kohler dealer locator at power.kohler.com. Get at least two quotes for comparison, since dealer installation pricing varies significantly.
Request a professional load calculation
Before finalizing the model, ask your Kohler dealer for a formal load calculation per NEC Article 220. This is especially important for all-electric homes or homes with unusual loads like pool pumps, EV chargers, or large shop equipment.
Calculator Output → Kohler Model Quick Reference
Run the generator size calculator and match your running watts to this table:
| Calculator Running Watts | Minimum kW (÷ 0.80) | Kohler Model |
|---|---|---|
| Under 5,600W | < 7 kW | 10RESAL |
| 5,600–8,400W | 7–10.5 kW | 14RESALMost common |
| 8,400–11,200W | 10.5–14 kW | 14RESAL |
| 11,200–14,400W | 14–18 kW | 20RESAL |
| 14,400–20,000W | 18–25 kW | 26RCL |
| Over 20,000W | 25+ kW | 38RCLC+ |
Where Kohler Models Sit in the Generator Size Spectrum
The 14RESAL (highlighted) is in the "Standby" tier — right where most homeowners need to be.
Generator Size Categories
Typical wattage ranges and what each covers
Phone charging, lights
Fridge + sump pump
Home essentials + window AC
Partial home + well pump
Whole home + small AC
Full home + central AC
Scale up to 22 kW for very large homes
Kohler Generator Installation — What to Expect
Installing a Kohler standby generator is a multi-step project that typically takes 1–3 days for a professional crew. Unlike Generac — available at Home Depot and online retailers — Kohler is sold exclusively through its authorized dealer network. This means you will not find a Kohler generator at a big-box store. The dealer model has trade-offs:
- Pro: Your installer is factory-trained and warranty-authorized. Kohler requires dealers to certify their technicians, which sets a quality floor that open distribution cannot guarantee.
- Con: Dealer density is lower than Generac in many rural and suburban areas. In some regions, the nearest Kohler dealer may be 50–100 miles away, affecting installation lead times and future service scheduling.
- Practical impact: Get quotes from at least two Kohler dealers. If your area has only one dealer, that lack of competition may result in higher installation pricing — worth comparing to a Generac quote in those cases.
Typical Kohler Installation Timeline
| Phase | Timeline | Who Does It |
|---|---|---|
| Site survey and load calculation | 1–3 days after inquiry | Kohler dealer |
| Permit application | 1–4 weeks (varies by municipality) | Dealer + homeowner |
| Generator delivery | 2–8 weeks from order | Dealer coordinates |
| Concrete pad pour + cure | 3–5 days | Dealer or concrete contractor |
| Gas line extension | 1–2 days | Licensed plumber |
| Electrical + ATS installation | 1–2 days | Licensed electrician |
| Generator connection + commissioning | Half day | Kohler dealer technician |
| Inspection + final approval | 1–3 weeks after install | Building department |
Total project timeline from first contact to running generator: typically 6–16 weeks depending on permit processing in your area. Plan accordingly if you are installing before storm season.
Kohler Generator Annual Maintenance
Kohler RESAL generators require annual professional service regardless of operating hours. The 200-hour oil change interval means most residential generators (averaging 50–150 hours/year in outages plus monthly exercise runs) will only need oil changes every 1–4 years. Annual service visits cover: air filter inspection, spark plug check, battery test, coolant check (liquid-cooled models), belt inspection, and firmware updates for the OnCue Plus monitoring system.
Annual service cost: $200–$400 through authorized dealers. Factor this into your total cost of ownership calculation alongside fuel costs using our generator cost estimator.
OnCue Plus — Remote Generator Monitoring
All Kohler RESAL generators include OnCue Plus capability — Kohler's remote monitoring platform that alerts you when your generator runs, reports on engine hours and battery status, and notifies you of faults before they become failures. The system connects via Wi-Fi and sends alerts to your phone.
Free Tool
Confirm Your Kohler Generator Size
Get the exact kW requirement for your home before contacting dealers — prevents both undersizing and upselling.
Frequently Asked Questions
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