The Kohler 20RESAL is a 20 kW air-cooled home standby generator that was sold as a package with a Kohler RXT automatic transfer switch. It first appeared around 2011. Kohler has since replaced it with newer models, but a lot of 20RESAL units are still protecting homes, and their owners still need straight answers about specs, fuel, parts and service.
Here is the short version. The 20RESAL makes 20 kW on propane and 18 kW on natural gas. It uses Kohler’s 999 cc CH1000 V-twin engine, a DC2 controller and a 200-amp RXT transfer switch. It was sold with a five-year or 2,000-hour warranty. Today’s equivalent is the Kohler 20RCA, which keeps the same engine family and the same ratings.
This guide gives you the full specs from Kohler’s own specification sheet, explains the confusing SA2 and SA7 codes, shows exactly how much gas the unit burns, and lists what it needs to stay reliable. You will also get honest help deciding whether to keep yours running or replace it.
Kohler 20RESAL at a glance
A 20 kW whole-home standby with a 200-amp transfer switch
These numbers come from Kohler specification sheet G4-210 for the 14RESAL and 20RESAL.
Quick answer
The Kohler 20RESAL is a discontinued 20 kW air-cooled standby generator rated at 20 kW and 83.3 amps on propane, or 18 kW and 75 amps on natural gas. It was packaged with a 200-amp Kohler RXT automatic transfer switch and a DC2 controller. Codes such as SA2 and SA7 are retailer bundle codes, not different generators. If yours runs well, keep it serviced. If it needs major work, the current Kohler 20RCA is the direct replacement.
How we put this guide together
We have not tested this generator ourselves. The specs come from Kohler’s own specification sheet for the 14RESAL and 20RESAL (G4-210, dated December 2011), from dealer listings, and from Kohler’s current product pages and Amazon listings for the replacement models, all checked in October 2026. Where we could not find official information, we say so.
In this guide
- What Is the Kohler 20RESAL?
- Kohler 20RESAL Specs at a Glance
- What Can a 20RESAL Power?
- Fuel: Natural Gas, Propane and How Much It Uses
- The DC2 Controller and RXT Transfer Switch
- Sound, Size and Placement
- Maintenance: What a 20RESAL Needs
- Common Problems and What to Check First
- Keep It, Fix It or Replace It?
- Replacement Options for the Kohler 20RESAL
- Common Mistakes 20RESAL Owners Make (With Fixes)
- Pro Tips From the Spec Sheet
- Real-Life Scenarios: Keep It or Replace It?
- Kohler 20RESAL FAQ
- Your Kohler 20RESAL Checklist
What Is the Kohler 20RESAL?
The 20RESAL is a permanently installed home standby generator. It sits outside on its base, connects to your natural gas line or propane tank, and starts by itself when utility power fails. A transfer switch moves your home onto generator power and back again when the grid returns.
What made the 20RESAL different from the plain 20RESA was the packaging. Kohler’s spec sheet says a 200-amp standard RXT automatic transfer switch is included with the 20RESAL. Its smaller sibling, the 14RESAL, came with a 100-amp switch and load center. So the letter L on the end tells you it was sold as a complete system. Kohler uses the same idea today: an RCAL model includes a switch and an RCA model does not.
The spec sheet lists these as standard: a corrosion-proof polymer sound enclosure, a polymer base that removes the need for a concrete pad, a hinged locking roof, rodent-resistant construction and a multi-fuel system that can be converted between natural gas and propane in the field.
What do SA2, SA4 and SA7 mean?
You will often see this generator listed as 20RESAL-SA2, 20RESAL-SA4 or 20RESAL-SA7. These are bundle codes used by retailers, and they describe what was in the box with the generator.
We could confirm one of them. A dealer listing for the 20RESAL-SA2 describes it as the 20 kW generator packaged with a Kohler RXT 200-amp automatic transfer switch that is not service-entrance rated, in a NEMA 3R aluminum enclosure. A similar listing shows the 14RESAL-SA3 as the 14 kW generator with a 100-amp, 16-circuit switch.
We could not find official Kohler documentation for the SA4 or SA7 codes. The generator itself is the same 20RESAL in each case. If you need to know exactly which transfer switch you have, read the model number on the switch’s own nameplate. That number is what a dealer needs for parts and service.
Key insight: SA7 is a package code, not a different generator. For parts and service, the numbers that matter are on the generator’s nameplate and on the transfer switch.
Kohler 20RESAL Specs at a Glance
| Spec | Kohler 20RESAL | What it means for you |
|---|---|---|
| Rating on propane (LP) | 20 kW, 83.3 amps | The most it can deliver on propane |
| Rating on natural gas | 18 kW, 75 amps | About 10% less on natural gas |
| Voltage | 120/240 V, single phase, 60 Hz | Standard household power |
| Engine | Kohler CH1000, V-twin, 999 cc | A Command PRO engine with hydraulic valve lifters |
| Engine power | 30.9 hp on LP, 27.1 hp on natural gas | Measured at 3,600 rpm |
| Oil capacity with filter | 3.0 quarts (2.8 liters) | Full-pressure lubrication with a cartridge filter |
| Controller | Kohler DC2 | Runs the generator and the RXT transfer switch |
| Transfer switch | RXT 200-amp, included | Automatic, in a NEMA 3R enclosure |
| Line circuit breaker | 100 amps | Protects the generator output |
| Sound level | 64 dB(A) exercise, 69 dB(A) full speed | Measured at 7 meters with no load |
| Size | 48 x 26.2 x 29 inches | Length, width and height |
| Shipping weight | 580 lb with transfer switch | A two-person delivery, at least |
| Battery | 12 volt, group 51, 500 CCA minimum | Bought separately |
| Warranty when new | 5 years or 2,000 hours | Premium limited warranty |
The engine
The CH1000 is the part of this generator that owners tend to like most. The spec sheet describes a Kohler Command PRO overhead-valve engine with hydraulic valve lifters, which means no routine valve adjustments and no lengthy break-in. It has full-pressure lubrication, an oil filter and an integral oil cooler. Those are features of a small industrial engine, not a lawn mower engine.
One note on ratings
Standby ratings assume normal conditions. The spec sheet says to derate by 4% for every 1,000 feet of elevation above 500 feet, and by 2% for every 10°F above 60°F. If you live at altitude or in a very hot climate, your generator makes a little less than the number on the label.
What Can a 20RESAL Power?
Twenty kilowatts is a real whole-home size. At 83.3 amps on propane, the 20RESAL can carry the everyday loads of a typical house: lighting, refrigeration, a gas furnace, a well pump, the kitchen, and one central air conditioner.
Kohler’s spec sheet credits its PowerBoost technology with excellent starting power. It gives one concrete example: the smaller 14 kW model can start and run a 5-ton air conditioner without dropping power to other appliances. The 20 kW unit has more in reserve.
Limits still apply. Two large air conditioners, an electric water heater, an electric range and a dryer all running together can add up to more than 83 amps. That is what load control is for. Kohler offered a Load Control Module for this generator with four power relays and two HVAC relays, so large appliances can take turns instead of all starting at once.
Tip: size against the fuel you actually use
If your 20RESAL runs on natural gas, think of it as an 18 kW generator, not a 20 kW one. That 2 kW gap is about the size of a water heater element. It explains why some owners see the lights dip on natural gas when the same loads would be fine on propane.
Want to check your own loads? Our Generator Size Calculator adds them up, and our guide to whole-house generators explains load management in plain English.
Fuel: Natural Gas, Propane and How Much It Uses
The 20RESAL runs on natural gas or propane vapor, and Kohler’s spec sheet gives exact fuel use at four load levels.
| Load | Natural gas | Propane vapor | Propane, liquid |
|---|---|---|---|
| 25% | 127 cubic feet per hour | 59 cubic feet per hour | About 1.6 gallons per hour |
| 50% | 161 cubic feet per hour | 82 cubic feet per hour | About 2.3 gallons per hour |
| 75% | 243 cubic feet per hour | 109 cubic feet per hour | About 3.0 gallons per hour |
| 100% | 281 cubic feet per hour | 136 cubic feet per hour | About 3.7 gallons per hour |
Here is how to read that. Most homes run a standby generator at a quarter to half load for most of an outage. On propane, that is roughly 1.6 to 2.3 gallons an hour, or 38 to 55 gallons a day if it runs around the clock. A 500-gallon tank is normally filled to about 80%, which is 400 gallons. So a full tank lasts about a week of nonstop half-load running, and longer if your loads are lighter.
On natural gas there is no tank to empty, but the supply has to be big enough. The spec sheet lists a fuel demand of 281,000 Btu per hour on natural gas and 340,000 Btu per hour on propane. The fuel inlet is 1/2 inch NPT, and the required supply pressure is 5 to 11 inches of water column for natural gas and 7 to 11 inches for propane.
Pipe size matters too. For the 20RESAL on natural gas, the sheet recommends a minimum of 1 inch pipe for runs up to 50 feet and 1 1/4 inch for runs of 100 to 200 feet. An undersized gas line is one of the most common reasons a standby generator stumbles under load, so have a gas fitter confirm yours.
The DC2 Controller and RXT Transfer Switch
The 20RESAL uses Kohler’s DC2 controller. The spec sheet describes it as one digital controller that manages both the generator and the RXT transfer switch.
- A two-line backlit display. It scrolls through generator status, voltage and frequency, engine temperature, oil pressure, battery voltage and run hours.
- Four buttons. OFF, AUTO, RUN and EXERCISE. In everyday use it stays on AUTO.
- Maintenance reminders. The controller tells you when service is due.
- Diagnostics. Kohler says it can display more than 70 diagnostic messages for the engine, generator and transfer switch.
- A built-in battery charger. A 2.5-amp charger keeps the starting battery topped up.
- An Ethernet port for OnCue. With the OnCue accessory, you can monitor the generator remotely.
The exercise function deserves a special mention. The DC2 offers an unloaded weekly exercise with complete system diagnostics, an unloaded full-speed exercise, and a loaded full-speed exercise that uses the RXT switch. The weekly exercise is the quiet one, at 64 dB(A).
The RXT transfer switch supplied with the 20RESAL is a 200-amp unit. The spec sheet says it is UL listed, comes in a corrosion-resistant NEMA 3R enclosure that can be installed indoors or outdoors, and is designed for use only with Kohler generators that have the RDC2 or DC2 controller.
Sound, Size and Placement
Kohler lists the 20RESAL at 64 dB(A) during the weekly exercise and 69 dB(A) at full speed, both measured at 7 meters with no load. For comparison, normal conversation is around 60 dB(A). You will hear it, but it will not rattle the windows.
The enclosure measures 48 by 26.2 by 29 inches, and the unit ships at 580 pounds with its transfer switch. The polymer base means it does not need a poured concrete pad, though it still needs a level, well-drained spot.
The spec sheet states that the generator is designed for outdoor installation only. Where exactly it may sit, relative to windows, doors and property lines, is set by the installation manual and your local code.
Service and repairs: know your limits
A standby generator is connected to your home’s electrical service and gas supply, and it can start by itself at any moment. Before any work, the controller must be switched off and the unit made safe, as described in the owner’s manual. Oil and filter changes are within reach of a careful owner. Electrical faults, gas work and transfer switch repairs are jobs for a Kohler dealer or a licensed professional. Keep working carbon monoxide alarms inside your home.
Maintenance: What a 20RESAL Needs
A standby generator spends almost all its life waiting, so small faults go unnoticed until the day you need it. Routine care is what prevents that.
- Oil and filter. The CH1000 holds 3.0 quarts with the filter. The spec sheet lists an oil drain extension with a shutoff valve as standard, which makes the job cleaner. Follow the intervals and oil grade in your owner’s manual.
- Air filter. The engine uses a dry air cleaner. Replace it on schedule, and sooner in dusty places.
- Battery. The generator needs a 12-volt, group 51 battery with at least 500 cold cranking amps. A tired battery is the classic reason a standby generator fails to start.
- Exercise. Leave the weekly exercise switched on. It keeps the engine lubricated and proves the system works.
- Keep it clear. Remove snow, leaves and weeds, and check for rodent nests around the base.
- Read the display. If the DC2 shows a maintenance reminder or a fault message, deal with it now, not during the next storm.
Cold climates
Kohler listed two starting aids for this generator. A 120-volt carburetor heater is recommended for reliable starting below 32°F, and a fuel regulator heater pad is recommended for the 20RESAL below 0°F. A battery heater was also available. If you live where winters are hard and your unit has none of these, ask a dealer about adding them.
For 20RESAL owners
Kohler Maintenance Kit for CH1000 Generators (17, 18 and 20 kW)
A genuine Kohler kit for 17, 18 and 20 kW generators with the CH1000 engine. Kohler’s listing says it includes the recommended air and oil filters and the correct amount of oil.
- FitsKohler CH1000 engine
- Generator sizes17, 18 and 20 kW
- IncludesAir filter, oil filter, oil
- BrandKohler
- UseRoutine maintenance
- Stock on listingIn stock when checked
- Why it works: everything for one routine service arrives in a single box, in the right quantities for this engine.
- Who it is best for: 20RESAL owners who do their own oil changes, and anyone who wants a spare kit on the shelf.
- What it solves: in a wide outage, filters and oil sell out fast. With a kit in the garage you can service the generator mid-outage.
- Keep in mind: confirm the engine model on your generator’s nameplate before you order. Retailers list Kohler kit GM62347 for the 20RESAL, so check the part number with the seller.
As an Amazon Associate we earn from qualifying purchases. Details come from the Amazon listing, checked October 2026.
For the general routine that applies to any generator, see our generator maintenance checklist.
Common Problems and What to Check First
We will not pretend to diagnose your generator from a web page. What we can do is give you the sensible order of checks before you call for service. Always follow the safety steps in your owner’s manual first.
| What you notice | Check first | Then |
|---|---|---|
| It did not start in an outage | Is the controller in AUTO? Is there a fault message on the display? | Check the battery and its connections, then the gas supply |
| It cranks but will not run | Is the gas valve open? Is the propane tank empty or nearly empty? | Have the fuel pressure and regulator checked |
| It starts, then shuts down | Read the fault message on the DC2 display and note it | Check the oil level, then call a dealer with the message |
| It runs but the house has no power | Look at the transfer switch and the generator’s line circuit breaker | Call a dealer or electrician. Do not open the switch yourself |
| The lights dim when the air conditioner starts | Are you on natural gas at the lower 18 kW rating? | Ask about load control or a soft-start kit for the air conditioner |
| It struggles in very cold weather | Does the unit have a carburetor heater and regulator heater? | Have a dealer fit the cold weather accessories |
Two habits make any service call faster and cheaper. First, write down the exact message on the display before you reset anything. Second, have the model and serial numbers from the nameplate ready. For general starting problems on any generator, our generator won’t start checklist is a useful companion.
Keep It, Fix It or Replace It?
A 20RESAL built around 2012 is now well into its second decade. That is not old for a well-kept standby unit with a commercial-style engine, but it is old enough to think ahead.
Reasons to keep it
- The engine is a proven design. The CH1000 is still used in Kohler’s current 20 kW model.
- Service parts are still sold. Kohler maintenance kits for this engine are available today.
- It is already installed. The pad, wiring, gas line and permits are the expensive part of any standby system, and they are done.
Reasons to plan a replacement
- The warranty has expired. Major repairs come out of your pocket.
- Electronics age. Controllers and transfer switch boards are harder to source than oil filters.
- Your home may have changed. A second air conditioner, an EV charger or an addition can push you past 18 to 20 kW.
- Newer units are quieter and better connected. The current models offer app monitoring and, on the 26 kW, a much quieter weekly exercise.
Rule of thumb: routine parts and a battery are worth buying for a 20RESAL. A failed controller, alternator or engine is the moment to price a new unit before you approve the repair.
Replacement Options for the Kohler 20RESAL
Kohler’s current air-cooled line replaces the 20RESAL directly. The 20RCA keeps the same ratings and the same engine family. The 26RCA is the step up.
| Feature | Kohler 20RESAL | Kohler 20RCA | Kohler 26RCA |
|---|---|---|---|
| Rating on LP | 20 kW | 20 kW | 26 kW |
| Rating on NG | 18 kW | 18 kW | 24 kW |
| Amps on LP | 83.3 | 83 | 109 |
| Engine | CH1000, 999 cc | CH1000, 999 cc | CH1006, 999 cc |
| Controller | DC2 | RDC2 | RDC2 |
| Enclosure | Polymer | Aluminum | Aluminum |
| Sound, weekly exercise | 64 dB(A) | 64 dB(A) | 56 dB(A) |
| Sound, full speed | 69 dB(A) | 69 dB(A) | 67 dB(A) |
| Weight | 580 lb shipping, with switch | 555 lb | 625 lb |
| Warranty | 5 years or 2,000 hours when new | Premium five-year limited | Premium five-year limited |
| Status | Discontinued | Current model | Current model |
One question to ask your dealer: the RXT transfer switch is designed for Kohler generators with the DC2 or RDC2 controller, and the current models use the RDC2. Ask whether your existing RXT switch can stay in place. If it can, you may only need the generator, and not the bundled package.
Direct replacement
Kohler 20RCAL-200SELS 20 kW Standby Generator with 200-Amp Transfer Switch
Today’s version of the 20RESAL package. It has the same 20 kW and 18 kW ratings and the same CH1000 engine family, with a new RXT 200-amp, service-entrance rated transfer switch in the box.
- Rating20 kW on LP, 18 kW on NG
- EngineKohler CH1000, 999 cc V-twin
- Transfer switchRXT 200-amp, service-entrance rated
- Sound64 dB(A) exercise, 69 dB(A) full speed
- Warranty on listing5-year limited
- Response time10 seconds
- Why it works: it is the same size and fuel demand as your 20RESAL, so your existing gas line and pad location are a natural fit.
- Who it is best for: owners whose 20RESAL needs a major repair, and whose home still suits a 20 kW unit.
- What it solves: a fresh five-year warranty, app-based remote monitoring and a new transfer switch, all in one order.
- Keep in mind: installation is a separate cost. Ask your dealer whether your old RXT switch can be reused before paying for a bundled one.
As an Amazon Associate we earn from qualifying purchases. Specs come from Kohler’s product page and the Amazon listing, checked October 2026.
Step-up replacement
Kohler 26RCAL-200SELS 26 kW Standby Generator with 200-Amp Transfer Switch
If your home has outgrown 20 kW, this is the next size up. It is Kohler’s most powerful air-cooled model and also its quietest during the weekly exercise.
- Rating26 kW on LP, 24 kW on NG
- EngineKohler CH1006, 999 cc V-twin
- Transfer switch200-amp automatic, included
- Sound56 dB(A) exercise, 67 dB(A) full speed
- Warranty on listing5 years
- Weight625 lb
- Why it works: 109 amps on propane, compared with 83 on the 20RESAL, gives real headroom for a second air conditioner or an EV charger.
- Who it is best for: homes that have added loads since the 20RESAL was installed.
- What it solves: dimming lights and nuisance shutdowns under heavy load, plus a much quieter weekly test.
- Keep in mind: a bigger generator needs more gas. Have your gas meter, regulator and pipe size checked before you order.
As an Amazon Associate we earn from qualifying purchases. Specs come from Kohler’s product page and the Amazon listing, checked October 2026.
For a full look at the current range, read our guide to whole-house generators.
Common Mistakes 20RESAL Owners Make (With Fixes)
Pro Tips From the Spec Sheet
- Use the oil drain valve. The spec sheet lists an oil drain extension with a shutoff valve as standard. It makes oil changes cleaner and quicker.
- Check the gas pipe size. The sheet recommends at least 1 inch pipe for natural gas runs up to 50 feet, and 1 1/4 inch for 100 to 200 feet.
- Know your derating. Expect 4% less output for every 1,000 feet above 500 feet of elevation.
- Ask about load control. The Load Control Module lets big appliances take turns, which matters most on natural gas.
- Add remote monitoring. The DC2 has an Ethernet port for Kohler’s OnCue system, so you can check on the unit while you are away.
- Keep the paperwork. A photo of the nameplate and a copy of the spec sheet save time on every service call.
- Service by the clock in long outages. Check the oil level daily when the generator runs for days at a time.
Real-Life Scenarios: Keep It or Replace It?
These are typical situations that owners describe. They are examples to help you decide, not quotes from real people.
🔧 The well-kept original
Your 20RESAL has been serviced every year and still starts on every weekly exercise.
Keep doing what you are doing. Fit a fresh battery, keep a maintenance kit on the shelf and add cold weather heaters if you need them.
Verdict: keep it
🧾 The big repair quote
The dealer has found a failed controller or alternator, and the estimate is large.
Price a new unit before you approve the repair. A new generator brings a new five-year warranty.
Verdict: replace with the 20RCAL
🏗️ The home that grew
You have added a second air conditioner or an EV charger since the generator went in.
More load needs more amps. Keep the install location and move up a size.
Verdict: replace with the 26RCAL
Kohler 20RESAL FAQ
How many watts is a Kohler 20RESAL?
Kohler's spec sheet rates the 20RESAL at 20 kW, or 20,000 watts, and 83.3 amps on propane. On natural gas it is rated at 18 kW and 75 amps. Both ratings are at 120/240 volts, single phase.
What engine does the Kohler 20RESAL have?
It uses the Kohler CH1000, a 999 cc V-twin Command PRO engine with hydraulic valve lifters and full-pressure lubrication. The spec sheet lists 30.9 horsepower on propane and 27.1 horsepower on natural gas.
What does 20RESAL-SA7 mean?
SA7 is a retailer bundle code, like SA2 and SA4. A dealer listing confirms that the SA2 bundle was the 20RESAL with a 200-amp RXT transfer switch. We could not find official documentation for SA7. The generator is the same 20RESAL, so use the nameplate numbers for parts and service.
How much propane does a Kohler 20RESAL use?
The spec sheet lists 82 cubic feet of propane vapor per hour at half load and 136 at full load. That works out to about 2.3 gallons of liquid propane per hour at half load and 3.7 gallons per hour at full load.
What battery does a Kohler 20RESAL need?
A 12-volt, group size 51 battery with at least 500 cold cranking amps. The battery was sold separately. The DC2 controller has a built-in 2.5-amp charger to keep it topped up.
What replaced the Kohler 20RESAL?
The current equivalent is the Kohler 20RCA, or the 20RCAL when sold with a transfer switch. It keeps the 20 kW propane and 18 kW natural gas ratings and the CH1000 engine, with an aluminum enclosure and the newer RDC2 controller.
Your Kohler 20RESAL Checklist
- Photograph the nameplates on the generator and the transfer switch.
- Confirm the controller is in AUTO and shows no fault messages.
- Check the battery age and fit a group 51, 500 CCA replacement if it is old.
- Change the oil and filters on schedule, and keep a maintenance kit on the shelf.
- Leave the weekly exercise switched on.
- Know your fuel: 18 kW on natural gas, 20 kW on propane.
- Keep the propane tank topped up before storm season.
- Add cold weather heaters if winters are hard where you live.
- Book a dealer service once a year.
- Get a replacement quote before approving any major repair.
The bottom line
A serviced Kohler 20RESAL is still a capable whole-home generator. Keep it maintained, keep the battery fresh, and know that the 20RCAL is waiting as a direct replacement when the day comes.
As an Amazon Associate we earn from qualifying purchases.
Sources: Kohler specification sheet G4-210 for the 14RESAL and 20RESAL (December 2011); dealer listings for the Kohler 20RESAL-SA2 and 14RESAL-SA3; Kohler’s official product pages for the 20RCA and 26RCA; Amazon listings for the Kohler CH1000 maintenance kit, 20RCAL-200SELS and 26RCAL-200SELS. All checked October 2026.
