I have a Generac 25kw watercooled natural gas whole house system. Installed to when I built the house 3 years ago. It powers the entire house including 4 HVAC systems, two refrigerators, pool equipment, and everything else in my house. With hurricanes we can lose power for up to a week, and have lost it for a few days since installation. Cost about $50-$60 Per day to run at normal load. I have no regrets but certainly suggest you go water cooled as it will last a lot longer and it is quieter. Furthermore we have a local company that comes out and services it twice a year for $400. I’ll never have another place without one. All in, mine was about $12 K installed, But that included the crane to lift it over And between two houses that are close together.

I guess I'm thankful I didn't need the crane, just front end loaders. But I did pay landscapers to hide both of them per county regulations.

I think it's worth noting that if you live in an area that floods. A elevated platform is a must.

I always found it entertaining to see genies on 5 ft platforms when I visit the east coast

I have a 20kW Briggs and Stratton. All of the 20kW units are roughly the same price ~$4500. Most are changeable from Propane to Natural Gas by switching a valve. Up through 22kW (Generac) are air cooled. There are "fairly" quiet. The Water cooled units start around 25kW and they are much quieter. You will pay a lot for the water cooled units.

Installation: You need a foundation. I can speak for Briggs & Stratton, they make lightweight concrete bases.

The real cost is the electrical and the fuel hookup. The closer the generator is to the fuel and electrical breaker, the better. Depending on where you are located, you may need both electrical and plumbing permits. If government permits are required, you will probably need professionals. No matter what, most electrical power companies require a 1-line diagram submitted and approved. If you do not have an external service entry disconnect, you will need to have the meter pulled by the electric company.

Every time this subject pops up I get in the mood for a generator. Then the reality set in. In the end after living in this house for over 22 years, we have only had 2 overnight power outages. Both were fixed before 24 hours. Both were a pain, but not worth the expense of a whole hour generator. I still am tempted to buy a small Honda inverter.

20KW Generac is what I have...... it has been excellent...… $7,000 Installed..... annual maintenance required..... have replaced the battery twice in 6 yrs.

Same here. I'm considering something in-between - installing a transfer switch and a portable generator.

The CL seller got back to me , him and his partner have 6 of these used Generacs . Per the seller they all run and have been serviced by Generac . A 15KW for 2000.00 is tempting I need to find out if a transfer switch box is included . More to follow :D

Thats where I am. No nat gas here so fuel is an issue. Fridge, well and sump pumps, a few lights/outlets, woodstove would be nice, septic... will run off a larger portable. Transfer switch is the key as said. I had a makeshift setup but really want something a little simpler/professional.

Do you move the circuits to the transfer switch from the main panel?

Bought a house that came with a 20kw propane Generac. Will run a/c and pretty much anything else we need. I do exercise it at least once a month. Propane is more stable than diesel that sits, and we use it for hot water and cooking as well.

Same situation as OP, retirement house. I don't know how I would futz with a pull start genset and an interlock.

Just spoke with the seller via text , the units include a built in 100 amp transfer switch . I will probably go look at them later this week one is still hooked up and running . So I'm thinking at the very least a 15KW will run well pump , fridge , lights and maybe AC/furnace . We do have an LP wall mounted heater in the dining room which is centrally located in the house that could be used vs. the heat pump/furnace if need be . I have no problem having to manually shed some circuits via the house breaker box if I have to as each power outage event hopefully is not too long . I also have a text into the electrician that wired my 2 car man cave garage to see if he is experienced in these installs . Will post updates as I go along . Thanks for all the feedback so far . SmileWavy

Have had a Generac 20K for nine years now. Living in suburban DC (where Pepco supplies the power) it's pretty much a necessity. I wouldn't change a thing- but I did finally change the battery last year.

It should self exercise once a week.

Is this self exercising thing super important? I have a 10K Generac hooked up to a transfer switch in my garage. I don't run it except when the power is off & I need to use it. Since we don't have much in the way of outages, I turn off the fuel valve, run it until it runs out of gas, & empty the tank into a container I use for lawn mower, etc. Our power is usually off a few hours max. Earlier this year the power company kept it off for maybe 24 hrs. & got a lot of push back from customers saying they purposefully kept it off. Mine isn't hooked up to run the whole house, just circuits for the fridge, freezer, & some lighting. The panel handles 7.2 Kw, & I'm thinking of selling my generator & buying a 7.5 Kw out door unit to replace it.

The self exercising mode is designed to run the generator at least once a month for 5 - 10 minutes to make sure all is well . The last thing you want is to be without power and the generator won't start :( For these larger generators with electric start you would also want to check/charge the starting battery .......... you are not going to pull start a 4 cylinder car engine :D

Mine is electric start & has (maybe luckily) always started up the split second I turn the key - that is after I put gas in the tank & open the petcock & chock it.

Have a 6500. Hardly use it. But when I do I run my entire house. Well, 4 Refrigerators, Furnas, everything. One time I had to run it for 5 days and never let me down. I have a 3900SQ ft. house with an apartment. Owned her over 10 years.

A few things to note:

Portable generators are really only designed to be run for 50 hours before you change the oil and spark plug.

Fixed install NG/Propane generators are typically, 100 hours between oil/plug change. The water cooled generators with electronic ignition last longer, maybe 250-500 hours.

By comparison, 3000 miles for a car, run on average 30 miles per hour, has 100 hours on it between oil changes.

Did that twice already!

That's what I have. Manual transfer switch. 7K generator. Outside feed where an RV plug used to be.
It will run everything I need to get by except my well pump. I still need a solution for that as it's on it's own service.