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John Pratt
02-09-2010, 2:01 PM
Just got power back last night which went out on the 28th of Jan. Really makes you appreciate having electricity when you don't have it for a while. Only thing kept us going was the fireplace for warmth and food (LOML can really cook with cast iron) and a small generator for the fridage and freezer.

After going through all that, does anyone have any experience with whole house standby generators? Like Generac or something like that. Everything in my house is electric including furnace and water heater.

Anthony Scira
02-10-2010, 11:36 PM
Ouch that is a long time without electricity! I bet those portable generators were nowhere to be found in the local stores.

John A langley
02-11-2010, 9:27 AM
John - In the last thirty years we have had three major power outages - all weather related. When the second one happened I purchased a 4400 watt portable generator (John Deere). We had power cords strung all over the house but we survived. Then one day I was in Lowe's and saw a power source for $300. I had my electrician install it for another $100. On the 3rd outage it ran most of the lights, the fridge, the furnace (propane), the TV, phones and the computers. Anytime we lose power for half a day of something we are comfortable and I don't live in fear of missing an OK/KU game. If I were to build a new house I would definitely put in a stand-by generator. I don't know about an all electric house - what size you would need. It is also a great peace of mind not to worry about frozen pipes. There is one down side - all your neighbors are mad at you for having power.

Mike Cruz
02-11-2010, 11:10 AM
I recently got a 15kW Generac portable generator to run my house in case of an emergency. It has a 50 amp breaker. So 50 amps is all that you can supply to the house. So it can pretty much run the entire house at once...EXCEPT for the dryer, heat pump (ours is geothermal), and ovens. Not that this generator can't run them, but if I wanted to run them, I would have to make sure pretty much everything else was off.

I considered the Generac 17.5kW version, but it still only had a 50 amp outlet/breaker on it, so it wouldn't have given me anything extra.

HD and Lowes carry the 15kW unit for about $2300. I had a 10% off coupon for Lowes, took it to HD to see if they would beat it and they did by giving me 15% off instead. So, I got it for $1900 before tax.

I used the Interlock swich, instead of a subpanel and a transfer swich. Saved a lot of time and money going this route, and I don't have to worry about only being able to power only certain things in the house.

Moving up to a dedicated house generator (smallest at about 20kw) jumps you into the $7000+ range. Not worth it for my needs.

John Pratt
02-11-2010, 3:04 PM
I was thinking about one of the permanent location standby generators in the 17K to 20K range. I know the the 17K will power up to 65 amps and the 20K up to 100 amps. I could get a 20K for about $6K plus another $2K for complete installation on natural gas, but I hate to fork over that kind of cash without knowing if they are really worth it and dependable. I don't know anyone who has something like this. While the power was out here it sounded like a generator factory. People were running them everywhere from 3K to 15K portables. I could probably get by with a 17K if (while I am at it) I change out the water heater to NG and maybe someday the heater. But that means more $$$.

Dave Ogren
02-11-2010, 5:12 PM
Guys,

Something is wrong with this whole posting. If I am reading it correctly it is talking about 15K, 17K and 20K and something about only 50 amp of power. Something is wrong.
I have a 40' diesel pusher motor home with a 7.5 KW diesel generator and it has a 50 amp. transfer switch. It will run two (2) heat pumps, microwave, hot water heater, and heat the diesel engine block at the same time.
Granted a motor home is a lot smaller than most homes, my point is 50amps from a 7.5 KW generator.
It seems to me that a 15K gen. should put out about 100 amps of power. A little small for a modern home but it is for an emergency.

Good Luck,

Dave

Peter Stahl
02-11-2010, 7:43 PM
I looked on the Generac site and the NG one is rated at 16kW continuous use which I don't think many people would have. It also says you can use a 65 amp breaker for the main. So if you do the math, 65 amps times 240 volts is 15.6 kW. That would be more than enough for my house. I would only really need to run the heater, freezer and fridge, plus a couple light. The unit also have a test cycle it goes though plus if you use NG maintenance is very little.

Mike Cruz
02-11-2010, 7:54 PM
I don't know the formula, but 15kW is rated for 50 amps, and 17.5kW is rated at 70 amps...per my electrician.

I don't know if having a diesel makes some sort of difference, but here is what I do know. Well pumps draw quite a bit of power upon start up. During this surge, a normal (maybe not your diesel) 7kW generator is required. Mention using a 5kW generator for your well pump to an electrician, and watch his face crinkle.

The point... to run EVERYTHING in your house all at once, you have (or at least I do) a 200 amp service. That will/should allow you to run everything at once. Let's hope you never do, your bills would be astronomical. If you are supplying your house with 50 amps, you are technically servicing it with 1/4 of that. So, while it could run ANYTHING, it can't run EVERYTHING.

In your motor home, the appliances may not draw as much amperage because everything may be downsized...I don't know.

For a house, sure a 7kW will work. But you need to be pretty selective in what you run. At 15kW, you can be less selective. At 30kW, you probably don't have to pay much attention.

What I love about my 15kW is two fold: It was (only) $2,000; and it is portable (even though I have it dedicated for the house...I COULD cart it off somewhere else IF I needed to.

NOTE: I have a 2000 square foot house with only my wife and me. Point...no kids and not a HUGE house sucking a lot of electricity.

Mike Cruz
02-11-2010, 7:57 PM
I've seen Guardian talk about a 60 amp breaker panel for their 17.5kW generator (looks just like the Generac), but their outlets on the unit are maxed at 50 amps, so I don't get it...

John Pratt
02-14-2010, 3:10 PM
I understand about the power differences between the motor home and regular home. But I think what I am trying to accomplish here (and yes it is overkill and I am being greedy) is to power the whole house if needed. Typically when the power here does go out, it is for a significant amount of time, IMHO, from between 24 hours and 72 hours at a time. This last outage was not typical at 170 hours, but I like being better safe than sorry and have grown accustomed to the creature comforts in the home.

Mike Cruz
02-14-2010, 4:20 PM
Yeah, John, I agree with your view. Personally, for the money, I decided that 15kW would do the job (with minor selective breaker juggling). If you want to run your whole house without ANY hickups, go with a 25kW home back up version with automatic startup. You will pay SIGNIFICANTLY more money this route ($2500-3000 vs $8,000-15,000). But if that is the level of comfort you want/need, you should go for it. I don't think you would be satisfied with the 7-8kW range generator.

John Pratt
02-15-2010, 3:53 PM
Thanks for the input. I know I can find honest and open opinions here.

Dave Ogren
02-15-2010, 4:58 PM
John,
Mike is probably right. I have a 5KW generator in my garage. when the power is out for a few hours I plug a few things into it. But if the power is out at diner time or ??? we go out to the motor home. Thank goodness the power is almost never out here, we average maybe 5 to 10 minutes per year. If I was to install a generator permanetly for my home and had natural gas already installed, I would be tempted to go in that direction.
I am a bigger fan of propane. The permanent gensets have a way of firing up once a month. propane or N.gas doesn't go bad and very little wear on the engine.

Good Luck,

Dave

Brian Elfert
02-15-2010, 11:00 PM
Guys,

Something is wrong with this whole posting. If I am reading it correctly it is talking about 15K, 17K and 20K and something about only 50 amp of power. Something is wrong.
I have a 40' diesel pusher motor home with a 7.5 KW diesel generator and it has a 50 amp. transfer switch. It will run two (2) heat pumps, microwave, hot water heater, and heat the diesel engine block at the same time.


You have a 50 amp transfer switch because the shore connection is 50 amps 240 volts. A 7.5KW generator will do about 30 amps at 240 volts or about 60 amps at 120 volts. The 8KW generator in my motorhome puts out 33 amps at 240 or 66 amps at 120.

60 amps at 120 volts is enough to run what you mentioned. All of those appliances combined will take right around 7500 watts to run.

You're not magically getting 50 amp 240 volt power from a 7.5KW generator.

Brian Elfert
02-15-2010, 11:09 PM
I have an 8.5KW standby generator. I don't try to run the whole house on it, but I have critical stuff like sump pump, garage door opener, furnace, fridge, and a few lights on it. (Okay, garage door opener not that critical.)

My major concern is not having enough load on the generator. It isn't real good for them not to run at low load. In fact, the generator had issues until I ran it for a few hours at near full load.

My central A/C only takes 20 amps so I could run it with the generator if it really got hot, but I would hate to see my natural gas bill. The generator can really burn up natural gas in a hurry.

Mike Cruz
02-15-2010, 11:44 PM
Uuuuhhh, yeah, I guess I should have clarified that I was talking about 50 amps of 220... sorry.