Educate me on backup generators

[PJorgen]

We (meaning my wife) have decided we need a backup generator. We live in a rural area with occasional outages, but my wife uses a CPAP and doesn't sleep well without it. Our home is on propane, so I assume the generator will be propane fueled.

So, Generac vs Kohler?

How many kW? Home is 2300 sq ft, stove and water heater are propane, oven is electric, other normal appliances are electric. We're on a well and use a mini split for heating and cooling.

I'm thinking of an auto transfer switch, any reason not to?

Anything else I should know?

 

[Chuckster in NJ]

KOHLER with automatic transfer switch.……. I have a few questions.
Do you have central air?
What size propane tank do you have?
Are you planning on any future electrical loads?

 

[txvwnut]

I run my house on a 6000 watt Generac but I don’t run my electric stove off of it or the dryer. I will not say how it’s connected to the house as it seems to upset all the sparky’s on here. Depending on how big of a unit you get the transfer switch may do the whole house or may only do certain circuits. You’ll basically need to figure out what circuits you want to run and size the unit and transfer switch to those needs.


Oh it’s not Kohler anymore as they sold off the power generation part of the company. The new name is Rehlko.

 

[Snapped-off]

Whatever you can get serviced/installed in your area if you're not going to DIY.

I have a 19k Generac with ATS. Everything I have is gas except the AC, so it doesn't get much of a workout.

 

[PJorgen]

KOHLER with automatic transfer switch.……. I have a few questions.
Do you have central air?
What size propane tank do you have?
Are you planning on any future electrical loads?

No central air, mini-split with three indoor units; 24k, 12k and 9k BTUs

500 gallon propane tank, no plans for additional loads.

 

[thammel]

I have an 8kw Winco generator. Powered by propane - buried 500 gal tank. It's been fantastic and takes care of almost everything in our 3000 Ft^2 house. Only things it doesn't power - the heat pumps and the electric oven. We have 2 refrigerators a wine cooler and a freezer. All on gen power. Also a well pump and propane fired water heater. It's been a life saver!!!

 

[steves_001]

Watch Costco for sales on Honeywell. They are rebranded generac and include the ts as well. 22kw for under 5000.

 

[The Cobbler]

Kohler is now called Rehlko , sold in 2024 and renamed

https://www.engines.rehlko.com/​

 

[rct]

calculate a propane burn per hour, you may need a larger tank to meet the vapor draw and to run for several days. With a limited propane supply, a smaller generator that will run the essential draws may be a better choice. Even a dual or tri-fuel portable can be a good backup. Her CPAP may run well off just a battery power unit/power station at night. That said Kohler was considered a little better than Generac but with the Kohler change to Rehlko anything is possible. There is cummins/onan as well. Whatever you can get served close. I still use a 5500w portable with a natural gas dual fuel kit. Works well enough for our 1-2 outages a year. Whole house would be nicer but there is always something else to spend the dollars on.

 

[mm08822]

The CPAP could be handled by a UPS. Sure it doesn't cover everything else but there are needs and wants.

I would get a whole house ATS. Forget the 8-10-12 ckt transfer boxes.

Easy enough to calculate the gen size, once the all loads are known. Gen size is usually driven by the big loads: ac, mini-splits, dryer, oven, hw heater. Even with all of these loads present, load shed contactors can be installed to lockout some of them if needed. Sometimes just a control wire interlock....much cheaper.

List the house sq ft, all electrical loads and kw rating that you want running for sizing. List those you don't want running during outage - helps to figure out what the overall install has to manage and how.

How long are your outages? 3 hours is way different than 3 days.
Will a permit be needed?
Who will install?
Who will do the routine maintenance?

If you want automatic coverage, you pay for that with the initial install. If you are the type who has no problem dragging out a gen to connect to a power inlet box, then you can save some $$$. Not having to get off the couch comes with a cost.

 

[loganb]

How many outages a year and for how long? What is the longest you've experienced?

If your location is correct....you may be able to do this with a whole house battery setup from a vendor like Ecoflow. Couple of solar panels you could deploy as required or permanently mount.

If you're periodically loosing power for couple hours max... battery based system could be less maintenance and more cost effective. If you've got long outages spanning days....gas or propane fired may be advantageous if you don't have a desire for a larger solar array

 

[BurtEggley]

Anyone today with electronics in the house needs an inverter style generator. The THD on non-inverter units is high enough to damage electronics which everything has electronics in it now - HVAC, refrig, washer, dryer, tv, audio visual etc.. Because of the cost, best to figure out what really has to run, and for how long. We use backup batteries for our CPAPs but we rarely lose power for more than a couple hours, a day at the most. If you get ice storms and are out for a week etc., then you need to figure the bare minimums. As others have said, a generator requires fuel so you have to think ahead where that fuel is coming from.

 

[PopcornSutton]

My backup genset is not a whole house unit, rather one that will drive selected circuits. We rarely have an outage so didn't feel the need. An outside connection, lockout plate on the panel, 6500W inverter generator will keep the well pump going, fridge/freezers, lights and selected receptacles. Won't do A/C, but I heat mostly with wood in the winter, so I'm fairly covered.

 

[BurtEggley]

My backup genset is not a whole house unit, rather one that will drive selected circuits. We rarely have an outage so didn't feel the need. An outside connection, lockout plate on the panel, 6500W inverter generator will keep the well pump going, fridge/freezers, lights and selected receptacles. Won't do A/C, but I heat mostly with wood in the winter, so I'm fairly covered.

most fridges have electronic circuit board in them today. Some well pumps do too. And it depends what you plug into the receptacle. Electronics need THD around 5% or less. Most rotary generators are up at 15%+. Works well out in the field running construction equipment or lights. Need an inverter style generator with 5% or less THD for anything electronic.

 

[mm08822]

Home standby gens are about 5% THD.

The smaller portable gens are anywhere from 5% - 30%. These are the ones to be concerned with. Need to read it's spec before buying.

Inverter style portables can be cleaner, maybe 2-3%.

 

[BurtEggley]

There is a Youtube channel, James Condon who repairs generators all the time. He does a load and THD test on each one when he is done. Of the hundreds he has done, I think there was one that was around 5% - 7% unless it was an inverter. That includes fixed Generac type units. I don't know what the specs are on new ones but someone should look carefully with all the electronics in things now, and even worse in the future. Someone the other night was talking about a stove they just bought and it is full of things like wifi, remote controls, all sorts of things. I was looking online not long ago at stoves and saw the same. Like I don't want to monitor a turkey cooking while I am driving on the freeway, or have hacker turn my stove on high while I am on vacation. But it does underscore the need to have a clean generator sine wave.

 

[PopcornSutton]

most fridges have electronic circuit board in them today. Some well pumps do too. And it depends what you plug into the receptacle. Electronics need THD around 5% or less. Most rotary generators are up at 15%+. Works well out in the field running construction equipment or lights. Need an inverter style generator with 5% or less THD for anything electronic.

I checked that before buying the one I did.

 

[logical]

I have the 22k Generac running NG. Autotransfer and will running everything including A/C. It has a module to shed off the A/C if needed, but pretty sure that's not happened. House is 3000+ sq ft.

To me, any set up that requires you to be home and willing/able to hook up and start a portable unit is of no real value.

 

[jblnut]

but my wife uses a CPAP and doesn't sleep well without it.

Like others have said put the CPAP on a UPS designed for a computer.

A propane genny will be the simplest from a fuel standpoint as propane doesn’t really go bad. Plus you’re using out of the tank already so you have a fuel storage area already.

I have a PTO genny here on the farm and have most things that are sensitive running through a UPS to smooth the power out. I can run my entire farm off a 24kw genny with room to spare, winter or summer.

Also have an 80kw LP genny in the chicken barn that turns on and does its thing automatically when the power goes out. It has a KatoLite genny and a Chevy based motor. Been a great unit so far.

 

[Stuart in MN]

Whatever you can get serviced/installed in your area if you're not going to DIY.

I agree. The two brands are more or less a horse apiece, go with a company that's well represented in your area for service and parts.
Something else to consider is there are any number of high capacity portable power stations available these days that would probably be able to keep her CPAP running overnight. If outages in your area usually only last a few hours I think I'd go with one of them first. One popular brand is Ecoflow but there are many others. https://us.ecoflow.com/

 

[wyliesdiesels]

I will not say how it’s connected to the house as it seems to upset all the sparky’s on here.

youll probably upset your PoCo and their lineman too if they find out

 

[BoostAddiction]

I have a 22K Generac. Worked fine, sort of, during a month-long outage. Later discovered that one cylinder had a pushrod shoved through the rocker. They replaced the entire engine under warranty.
We are connected using an ATS, and have a 320 gallon tank. Our home idles at 700-1000W, but we turned off the generator at night to conserve propane.
We are happy with the choice, but if a CPAP was the only reason to get a generator, I'd look into a small battery system for it. If you were worried about a long outage, get a small 2000W Honda standalone generator to charge the battery.

 

[mike93lx]

youll probably upset your PoCo and their lineman too if they find out

Hopefully they don't find out because someone got hurt or killed

 

[Two Door]

FYI - The Google-able term for the small battery systems is Portable Power Station

 

[Chuckster in NJ]

Hopefully they don't find out because someone got hurt or killed

I use to find these "whips" on some jobs and the owner always paid a $500 penalty OR they could go to court and gamble on getting a $2000 penalty.

BTW! Here is a KOHLER generator at Costco……… This is a nice machine!

 

[PJorgen]

Thanks for all the info and great suggestions! I’ll find a local pro installer and go from there.

 

[theoldwizard1]

We (meaning my wife) have decided we need a backup generator. We live in a rural area with occasional outages, but my wife uses a CPAP and doesn't sleep well without it. Our home is on propane, so I assume the generator will be propane fueled.

So, Generac vs Kohler?

Kohler ! My buddy loves his. Where he lives they get low voltage and on again/off again outages. His neighbors Generac starts and stops and start and stops. His Kohler just keeps humming until the voltage id stable.

I hope you have DEEP POCKETS ! Typically, any permanent generator must be sized to handle the maximum house load or have builtin load-shedding. This is $$,$$$ !

Buy your wife a battery powered backup device, like a Bluetti. Then is you still want a generator and are WILLING TO PLUG IT IN when necessary, have a generator interlock installed in your load center (breaker box) and a generator inlet. You can likely run most things in your house on a 3500-4000W (peak) inverter generator.

EDIT :

Re-read original post. No portable generator is going to run a mini-split (unless it very, very small).

 

[theoldwizard1]

Kohler is now called Rehlko , sold in 2024 and renamed

https://www.engines.rehlko.com/​

I think that is small engine only.

Kohler generators have not used Kohler (or Onan) engines in many years !

 

[mm08822]

Kohler ! My buddy loves his. Where he lives they get low voltage and on again/off again outages. His neighbors Generac starts and stops and start and stops. His Kohler just keeps humming until the voltage id stable.

I hope you have DEEP POCKETS ! Typically, any permanent generator must be sized to handle the maximum house load or have builtin load-shedding. This is $$,$$$ !

Buy your wife a battery powered backup device, like a Bluetti. Then is you still want a generator and are WILLING TO PLUG IT IN when necessary, have a generator interlock installed in your load center (breaker box) and a generator inlet. You can likely run most things in your house on a 3500-4000W (peak) inverter generator.

You will save enough money that you can take your wife out to dinner once a week for more than a year !

It's called configuration parameters. Has he ever changed them? It's like having a power seat in your car and never setting it for your situation.............

 

[PJorgen]

In response to those who’ve suggested that a UPS or portable power supply would work for my wife’s CPAP, I understand that. The CPAP just triggered the discussion of backup power.

We’re getting older (who isn’t?) and enjoy the comforts of our home. No power means no water (we’re on a well), no heating or cooling, no internet, no lights, etc. We can afford a good system, I‘ve budgeted up to $25k, and feel this is an investment in our future comfort.

 

[mike93lx]

In response to those who’ve suggested that a UPS or portable power supply would work for my wife’s CPAP, I understand that. The CPAP just triggered the discussion of backup power.

We’re getting older (who isn’t?) and enjoy the comforts of our home. No power means no water (we’re on a well), no heating or cooling, no internet, no lights, etc. We can afford a good system, I‘ve budgeted up to $25k, and feel this is an investment in our future comfort.

25k will git r done for sure

 

[mm08822]

In response to those who’ve suggested that a UPS or portable power supply would work for my wife’s CPAP, I understand that. The CPAP just triggered the discussion of backup power.

We’re getting older (who isn’t?) and enjoy the comforts of our home. No power means no water (we’re on a well), no heating or cooling, no internet, no lights, etc. We can afford a good system, I‘ve budgeted up to $25k, and feel this is an investment in our future comfort.

That's a very generous budget. W/o seeing any details, I'd say $12.5 - 15K would cover most 24-26kw situations (IME). Usually the budget is too small!!!

 

[American Locomotive]

I think that is small engine only.

Kohler generators have not used Kohler (or Onan) engines in many years !

The entire energy and power division was spun off as Rehlko. The engines and industrial stuff is all Rehlko. The home generator stuff IS owned by Rehlko, but appears to be using Kohler branding ...for now.

Kohler/Rehlko residential generators 26kW and under all use Kohler V-Twins, the exception being the 24kW model which is liquid cooled. Anything bigger than 26kW on the residential side is using industrial 4 and 8 cylinder engines.

 

[wyliesdiesels]

Where he lives they get low voltage and on again/off again outages. His neighbors Generac starts and stops and start and stops. His Kohler just keeps humming until the voltage id stable.

sounds like someone screwed up on the transfer switch programming.

 

[wyliesdiesels]

no internet,

all internet and computer equipment should be connected to a good UPS regardless of having a generator...

 

[txvwnut]

youll probably upset your PoCo and their lineman too if they find out

They've actually seen it and have no issue with how its operated.

 

[shade]

Bought a 22kw generac with an ATS for $5900 on Amazon and couple months ago.
Local electrician installed for $1900.
That should handle almost our entire load should we need it. AC, well pump, oven, etc.
Well under your 12k budget.

 

[DrinkMan]

How close are we to having battery backups as a viable/affordable option? I keep looking at the Tesla Wall and wondering if that is "ready for prime time" as a simple backup. In the last 40 years, we have had many 1 to 3 hour outages, about ten 1 to 3 days, and one 5 day outage. That is for multiple houses (worst was hurricane Helene on St Simons). So, I'd like something that could support 3 days full house.

Are battery backup "generators" viable and who has a good support and installation system for those of us without solar panels?

With the 25k budget for @PJorgen 's situation, is it a decent idea....yet?

 

[mike93lx]

How close are we to having battery backups as a viable/affordable option? I keep looking at the Tesla Wall and wondering if that is "ready for prime time" as a simple backup. In the last 40 years, we have had many 1 to 3 hour outages, about ten 1 to 3 days, and one 5 day outage. That is for multiple houses (worst was hurricane Helene on St Simons). So, I'd like something that could support 3 days full house.

Are battery backup "generators" viable and who has a good support and installation system for those of us without solar panels?

With the 25k budget for @PJorgen 's situation, is it a decent idea....yet?

They' re very viable for short outages, but not for providing backup power on a long one.

 

[Innovate1]

Not really what the OP is looking for but I bought an F150 hybrid with 7.2 kW inverter. Use it when towing my camper and don't have hookups. Also can power up the house although it can't power everything. And I would need to be there. Our outages are very infrequent and it seems good for us.