I sell and install them. A 22kw should be fine and is usually good enough for 80% of the homes out there. However, a 24kw is only a few hundred dollars more and the install is the exact same cost. And if on natural gas you won’t see the advertised kw. A 22kw is only going to get around 19.5kw running natural gas vs propane. Probably still good enough, but something to consider. Especially if you ever expand your electrical consumption.

 

I honestly wouldn't own one, too noisy
House 2 lots over, big lots at that, could hear it running inside my brick construction house.

 

I am about to get a plug put in to put my portable 9500 gas generator into my box and getting a lot of education on what it shows it runs and what it really runs and what your AC says it needs and what it really needs. Its a new wave of buyers and I am in Kingwood where it will go off on a clear day with no weather at all. Theres something else going on out here that needs to be addressed with the lines or something.

 

It's the same here in Rockport, in my neighborhood. I called and left voicemails to my state house rep. His chief of staff called me back and we had a good conversation. She told me she was "the head honcho" and that she would get to the bottom of it. AEP was the subject, and I told her about our "biweekly outages" that have no explanation or consequences. A week or so after talking with her, a lady from AEP called and seemed like she was concerned and had lists made of what happened each time the power went out. They ranged from "wind" to maintenance. I didn't leave the conversation feeling that it was going to end, and I could tell she didn't know, either, but she seemed like she got in trouble for it or was trying to make sure that I was not going to cause any more trouble. Either way, I know what to do if it becomes a problem again. That was a couple months ago and we only had one outage since, just due to some wind. We all know this never used to happen, only occasionally once a blue moon if there was a major storm.

 

A soft starter makes a big difference on the inrush amps on a central ac unit. I installed one on my ac years ago and have been using a 11,500/9,200 generator to run the whole house when needed.

EasyStart Soft Starter

 

Let's stick to the specific question please gentlemen.

 

As Jkmoore said, with the way they rate the power input, running on natural gas it will have less output than the number it is rated for. It simply doesnt make power the same.

I would get the 24kw. The fuel burn will be nearly identical. This one doesn't show the 24kw but you can extrapolate.

 

I have a 22kw and my house is about 2200 sq feet. Runs without a flaw. My brother has a 24kw but he has a pool , 3 freezers and about the same square foot as mine. The pool and all the appliances is why he went with a 24K and it ran flawless 3 weeks ago for about 4 days. Get one ...

 

Typically, you can look your usage up on your electricity supplier's website. I was able to do that and was surprised to see that my max hourly usage was 8K. Based on that I installed a 14K Guardian series Generac generator with the auto transfer switch. Works great and haven't had any issues with it.

 

What did your calc come up with vs the 22kw gen size

There are alot of items you need to examine. Oven p\or stove elect or gas? etc.
Do you want to think about loads or just use everything like on utility power?
You don't want to start your 5 ton HVAC and have the Gen Bog and lights flicker.
This could affect other electronic items.

The 22kw really should more than do it though.

 

Size matters. I don’t and will not be flipping breakers to accommodate generator load capacity . 30 kw deisel - 7 days (24 hr ) run rate on fuel tank.

 

I run my entire 2,086 sqft house on a 13kw TriFuel portable generator. I had a natural gas line run to it and plug installed next to the panel. Most of my lighting is LED, oven is gas, hot water heater is gas. The generator has 9k running watts on natural gas and doesnt even notice when the AC kicks on. I paid less than $2500 for the generator, plug and gas line plumbing

 

3500sq. ft home, two AC units are my largest electrical loads if I’m thinking correctly. I went with the recommendation for a 24kw. My considerations were that I had/have a little wiggle room for some additional load and the fact that if I move, I’m able to take the unit and I’m likely able to be able to support another home that will likely be smaller in sq. Ft but more dependent on a supply (shop, freezers etc.) That was my “logic”.

 

Guys I just want to point out the square footage of a home has really no bearing on the size generator you need. It all comes down to load balancing and what your consumers are. Having a gas dryer, gas water heater, gas cooktop and gas furnace, along with all LED lightning and you might be able get I get by with a 10-12kw unit easily on a 3000sqft home. Especially if you have multiple circuits on home runs with their own breakers. But a 2000sqft house with those same appliances being electric (and the number and size of them) and multiple users on shared circuits could easily require a 22-24kw unit or more. And your main coming in has a lot to do with it too and could even be required to be updated to handle the loads properly. There’s many variables, but sqft isn’t really one of them.

 

I run my whole house off a 11,500/9,200 generator. Went over 2 weeks after one of the storms running off the generator. Have a gas furnace and went about a week after the hard freeze. My generator rating number is for gas but I run it on natural gas with a conversion kit. I guess it just depends on how much money you want to spend. If money isn't an object I would get something that's not air cooled and has a real oil pump and filter. Get the largest you can afford for some piece of mind. I'm sure you don't need as much as you think unless you have more than one central AC unit and pulling 90+ amps each when they start.

 

I have a 5-ton AC unit that used to have an LRA of 150 amps. I installed an Easy Start soft start and dropped the LRA to 57. Since I dropped it, I can now run my entire house on a 13kw portable generator. Peace of mind without spending $8k+ for a standby generator. All in, my setup cost me less than $2500, but I installed my own breaker, interlock, and 50-amp inlet. I also installed the soft start. All of my major appliances that can be natural gas, are natural gas.

 

Guys there’s a huge difference between a portable generator and a standby generator. The main one being a standby will automatically start and power your house completely like the main power (if sized and installed correctly) and a portable generator may run everything (although not normally) and won’t automatically start when power is lost. Of course the standby will cost more, but won’t require you to manually do anything or keep refilling fuel tanks every couple of hours. A standby generator is a huge convenience and somewhat of a luxury item. If you can afford one, they are the nicer/more convenient option. And of course they offer benefits of not having to be home and knowing that if the main power goes out you aren’t losing items in your fridge and freezers, pools and septic systems aren’t freezing up, or that your house is hot and humid. Nor are you having to store up multiple cans of fuel or stand in long mines at the pump to try and get fuel after an outage.

I point all this out bc there are several references to portable generators and being cheaper. Trying to compare the two is like apples to oranges. They aren’t in the same category or conversation.

 

If I could afford the minimum of $8K to power my house with a standby generator, I absolutely would. That being said, with my portable generator plumbed to natural gas, I can safely power my entire house through most any disaster. Also, those $8k generators are no quieter than the one I own.

Truth be told, if I hit the lottery tomorrow, I'd get a water-cooled standby unit.

 

As a follow-up to my original query, after doing more research, asking questions and getting 4 quotes, we are going with a Generac standby generator. As some others have said, I currently have a large portable, complete with transfer switch on the house. That genny will run the whole house, as long as we manage our usage, such as not running the AC and the oven at the same time. However, as JKMoore pointed out, I got tired of having to set it up (often in the middle of a storm), breaking it all down and fueling it 2 to 3 times a day. JKM also pointed out an important factor that some might not consider - loss of food if you're away from home during an outage. I'm also not getting any younger.

Anyway, we can afford it and the Generac seems like a good decision at this point in our lives. Thanks to everyone for the input.

 

Good choice. My mom was complaining about hers about 2 months ago before the storm hit because she could not understand why she made the investment. Now, it is the greatest thing since sliced bread after running her house for 5 days after the big storm . LOL

 

jkmoore03, how big of a propane tank would you need to run a 22k standby generator? We don't have natural gas in my neighborhood. How much would it take to run it for 1 week, 2 weeks?

 

I have a 500 gallon propane tank dedicated to my 22kw. I can get about 5-6 days out of it with some load balancing. Meaning I’m not using one of my 50 gallon electric hot water heaters (I have 2) and we aren’t washing/drying clothes. It will definitely run these extra appliances, but during Harvey I wasn’t sure how long we would be without power so I cut back on usage on non essential things to burn less fuel. My house is all electric with a well and septic too and I was fine. We could have shut things completely off at night and stretched it out, but we were sure we could get supplied. Also remember that you only get 80% max capacity on a propane tank. So a 500 gallon will only net you 400 gallons.

There’s no exact science, but managing your load helps. Between 1/2 and full load they typically burn 4-5 gallons per hour on propane. I always advise people to buy a tank so they can get as big as they can. A lot of times propane companies don’t want to rent oversized tanks. And if you buy a tank you can get propane from anyone. That’s also important during a storm. My normal supplier was flooded out during Harvey and I was able to buy from someone else.

 

A backup gen is great....as long as your tank is full when the gen comes on.

I have two 250s. When one gets down to 10% I switch to other tank valve and call for a refill. So I always have 250. I own them and numerous points of service around me so reasonably confident I can get a fill.

 

I was late to this thread. A 22KW is more than enough bigfost. 24kw if you want to have closer to 22kw true output.
I have tandem AC units (4 ton and 5 ton), electric stovetop, electric ovens and all the other miscellaneous junk a house has, plus a bunch of kids that don’t know that a light switch can also turn the lights off and I can run everything and only draw about 18kw. I have run an amprobe test a few times just to check my meter.

Not that it matters but my house is 3300sq/ft and has huge open ceilings for the living room and foyer so the ACs work hard.

 

I have not bought bulk propane in many, many years. What does propane cost now?

 

Refilled my 500 gallon tank on 5/14/2024 and paid $2.80 per gallon. My tank supplies my home as well as the generator. I refill when the tank level drops to 50%.

 

Last time I bought 12/28/23 it was $2.68.
Price various depends on location and vendor.
Having auxiliary power gets expensive, no way I can afford or justify going large. My 7000 running watt inverter unit running pump gas suits me just fine.

 

When you get your generator "sized" does someone actually do some kind of load analysis and actually measure and calculate the size genset best for your house or do they just use their experience and do a walk around and see what is gas, what is electric, etc and then make a recommendation.

 

we can do an actual load calc and sometimes need to for larger projects, but 90% of the time we can gauge by just seeing what you have. Residential installs are fairly straightforward.

 

I have a 20 KW Kohler (installed in 2019). My house is 2750 sq ft, 7 total tons of HVAC (3 ton and 4 ton units), gas dryer, gas heat, double electric ovens. My generator barely grunts when an HVAC unit kicks on. I have had no problems and it runs everything with ease. I can highly recommend Kohler.

 

Interesting. Is there a market for used Generac standby units? I already have the ATS installed.

 

i'm sure if you posted it up for a reduced used price it'd sell quickly.