Home Forums Hunting & Shooting Hunter's Campfire Generac generator question

When you say AHU do you mean air handling unit and not a regular air conditioner? I am running 17 tons of air conditioning and that may be the primary difference between our needs.

I will get a second and probably third opinion, I ran their site calculator and came up with the 49 kw. That was my rough unprofessional calculation. The one that should know did the same estimate and came up with 48 kw.

The ironic part is if that is true then the 48 kw is normally aspirated which was going back to part of my original question. It seems to be the only one in the bigger generators that is NA. That may be the cut off point for the next bigger engine.

24kw is the same as having a 200 amp main in you house. Use this formula to help determine the size kw generator you may need/use.

amps x 120 volts = watts

200 x 120 = 24,000 watts or 24kw.

Yeah, unless there's an electricity draw we don't know about... 49kw is a LOT of generator!

I have a 27kw PTO generator that will run the whole ranch. Both houses, shop, water well, 4 refrigerator/freezers, and a/c or heat on the houses.

There's 200 amp service at the power pole.

Sounds like they could be motivated to over-sell you, Bob.

200 amps x 220 volts = 48 kw. Right? The vast majority of the power usage at my house is 220 volts.

Not sure that they are trying to oversell me because the price difference between the 27 kw unit and the 48 kw unit was only $5,000 approximately.

I am dazzled reading through this thread. When we lived up north, I had my service set up so I could isolate off the grid and power up the house with my 8000 watt Miller welder during outages. I thought I was in high cotton. Of course, our outages generally happened in the winter when we were primarily wood heating and even in the summer we didn't really need AC. Also, we cooked and heated water with gas. We could keep everything we needed going and the lights didn't dim when the water pump came on so I was living large.

You may need it...

My electrician said it's possible that I may have to run the central heat in both houses fine, but may have to start them at different times so they don't both hit the power source with start-up at the same time.

Was talking to a friend today and he said Generac priced a unit for him at $35-38k...

I think I paid $3600 for the PTO generator. (Tractor not included) Most of the cost of a big generator is the engine to run it. Already had the tractor, so that was cheaper for us.

Longbob - I am feeding 12 tons of cooling.

Two things to consider in addition to the acquisition cost is panel upgrades, auto cutover switches, and they like to calculate installation cost based on sizing. It takes them just as much time to install a 12kw as a 24kw, but the typical install cost is twice as much for a 24kw.

I had a contractor pour the slab, I purchased the Kohler from the local dealer and had my electrician do the hookup. The dealer came back to "test" the system. But I saved $3,500 on the turnkey price. It's a little bit of a racket...

Geez! How big of a generator was he being quoted? Was that installed? The cost of the generator was about $2,000 below the list price that I see online and the install was pretty pricey. The total with tax, running all the gas lines, concrete pad, switches, etc…..was $28,800. The 27 kw was $23,700 after they viewed the site. They originally said it would be $21,000 ($22,732.50 with tax) for the 27 kw, but that wasn’t a couple of nuances.

Look in your breaker panel and see what size main breaker you have. You have to remember that at 220/240, you only use 1/2 the amps you do at 110/120.

You also have to remember that 220/240 amp breaker is pulling 110/120 off each leg. So the formula is still correct when figured at 110/120. Your calculation is incorrect.

You can see from the post above the cost difference between the 48 kw installed and the 27 kw installed. You are right that there isn’t much difference between the cost of installation. The 48 is a bigger unit so there is a bit of a bigger slab, but that isn’t that expensive. It was somewhat due to the location to put it that will require a little extra location issues. Not much, but that did factor into any size I would have gotten.

There really isn’t a material amount of difference in overall cost and basically doubling the capacity.

We've had a 22k Generac for over 7 years. It has worked great every time we needed it. We had to get the gas company install a higher flow meter. The installer told me generators need volume and some places need a larger diameter line.

I am out of town at the moment, but I will look at the breaker panel. I do know this. I was trying to add another garage/apartment/mother in laws building right off my driveway. It had been planned since we built the house 20 plus years ago. The electrician I had been using for years told me that I could not add anything with my current panel because it is at the edge of capacity. He said it would require me to upgrade the entire panel to a 400 amp service. I think the cost on that alone was $5,000 installed.

If whatever size main breaker you have in your house is not giving you any trouble, use the formula and figure what size kw generator that will equal to. and the same size kw generator will not give you any problems.

If you want bigger, that's your choice.

In case you missed it, this is wrong. 220 single phase gets 110 from each leg.

I am not sure what you mean about it not giving me any trouble? Can you be more specific? The only trouble I guess I am having is that I cannot add anything to my house currently without upgrading from a 200 amp service to a 400 amp service. Maybe that is the only trouble I am having.

Also, while you are at it, make sure you have surge protection on every panel. It will save your large appliances and they are cheap as chips to install - If you have room on your panel that is...

You are right and I had the industrial style surge protectors added to each panel. I have three of them. I also have lightning rods installed on the house last year. We had three really nice houses burn to the ground very close to me from lightning strikes.

Ok, what I meant is that you are not having problems with tripping breakers. If you turn on the stove or ac or crank up the welding machine, and you trip a breaker. If this is happening, you need to upgrade to a bigger main breaker in your home. You stated that you were maxed out on a 200 amp main. Who told you or how did you/they come to this conclusion? Getting a bigger generator will let you run more, but if you haven't got the circuits, you're not going to run more than is already there. And, when the generator is not running, you will be back on the current system.

Thanks for the clarification. Yes, I will trip a breaker every now and then if I am using my welder and my air compressor kicks on especially in the heat of the summer. From a post above I mentioned that I wanted to add another garage apartment and my current electrician told me that it wasn’t possible to add to my current panel. There wasn’t enough capacity since it would also be air conditioned and electric stove/oven/water heater. The next step up would be a 400 amp panel which is the next step that my local utility will allow.

Just curious. Are you an electrician? I am not and don’t claim to be. What perplexes me is that are you saying that it is pointless to have any generator above 24 kw if I have a 200 amp panel? If so, why would they recommend a 48 kw generator if it is twice the electrical capacity of my panel? Wouldn’t the other 24 kw be sitting unused?

Longbob, Oldman03 is spot on with his info and advice !