I live in a rural area, looking to get a generator for my house. I want to get a portable one in case it needs service. Friends that have a permanently mounted standby always complain it’s hard to get someone out to service/fix it. I would like to run my water pump, heat pump, water heater, central air, fridge and a light or two and the tv. If I add all the amps up in the fuse box it goes to about 300 amps, can someone tell me what size generator in watts that would require? I’ve tried doing the math but I’m stupid. I’m thinking a 9000-10000 watt generator would work? Thanks for the help.
-
Having trouble using the site?
Contact support
Whole house generator
- Thread starter Pre-64
- Start date
10 KW generator is only about 40 amps...
A permanent mount whole house biggest you can REASONABLY get is 22kw... that will run about 90 amps... Most will not run central HVAC or at least not recommended. They also have auto transfer switches and a bunch of other stuff...
Most portable interconnect kits are limited to ~30amps.
And you dont do an amp draw assessment by adding up the breaker panel, way more involved than that. You aint drawing 300amps as your main shutoff is likely a 200a breaker
A permanent mount whole house biggest you can REASONABLY get is 22kw... that will run about 90 amps... Most will not run central HVAC or at least not recommended. They also have auto transfer switches and a bunch of other stuff...
Most portable interconnect kits are limited to ~30amps.
And you dont do an amp draw assessment by adding up the breaker panel, way more involved than that. You aint drawing 300amps as your main shutoff is likely a 200a breaker
Cummins has a kw calculator on their website. Real easy to use. My SWAG for your house is 25kw.
Anything higher than 22kw from Generac or Cummins Onan(I am 95% sure) goes to water cooled and the price SKYROCKETS...
22kw Generac is like $5500-6000 plus installation(couple thousands) plus needs a 500 gallon propane tank minimum.
Ive done a TON of research on whole house generators...
To the OP: how many times in the past 5 years have you been without power? Thats the question that was asked to me by a few people including the Generac and Cummins sales guys...
Buy an engine drive Welder.
My Lincoln Ranger 250 GXT is a 11000 watt generator and has a 50 amp 220v plug you can wire into your panel with a heavy duty cord with the help of an electrician.
$4500 plus you get a welder...
My Lincoln Ranger 250 GXT is a 11000 watt generator and has a 50 amp 220v plug you can wire into your panel with a heavy duty cord with the help of an electrician.
$4500 plus you get a welder...
One quick note is that for anything needing heating, such as house heating, water heating, cooking and such, it's way more efficient to use the fuel to generate heat directly rather than to make electricity with it and use the electricity to make the heat. If for example you were to put in a big propane tank you could run the water heater and house heater and cooking off that.
Another option is Briggs and Stratton Commercial. A buddy of mine sells and installs them. Says the service and warranty R&S is much better and they are more reliable.
- Nov 3, 2010
- 9,702
- 20,402
Generac has a calculator on their page as well. 22kw is what it told me and I run gas for water and cooktop. That also means I have to turn the shop off or go bigger.
Generators are like tractors, get more hp than you think you need.
With a full sine inverter you can make 220VAC from a 9V battery, just a matter of the conversion efficiency...
When we do need the generator i just wire it up to the HVAC disconnect outside and back feed the panel after turning off the main breaker from the meter and that's enough to run the refrigerator, lights, hot water, and the TV
When we do need the generator i just wire it up to the HVAC disconnect outside and back feed the panel after turning off the main breaker from the meter and that's enough to run the refrigerator, lights, hot water, and the TV
Generator electricity is expensive electricity. I have natural gas heating, cook top, and water heater. I also have a gas fireplace. I had an electrician wire my panel with an appropriate disconnect and back feed so I can run a portable generator for electricity. We don't loose power all that much but it happens on occasion. I can run the fridge, lights, etc, with no problem and heat if I need it. I have a 6800 watt Rigid generator from Home Depot. If I keep the load at 50% or so I can go about 8 hours on 5 gallons of gas. We treat not having electricity like camping out without the bugs.
Pros and Cons and Compromises...
If you are talking about running a whole house, you are talking in the 30 to 40 kw range. That means water cooled, whether it’s NG, Propane or Diesel. Propane will store forever - but takes 3.5X as much fuel for the same output as diesel. Diesel stores for about a year. Obviously if you can slim down your demand for power, you can get down to air cooled range and also include gasoline. But of course gasoline stores for even less time. But as was just said - generator power is expensive!
If you are talking about running a whole house, you are talking in the 30 to 40 kw range. That means water cooled, whether it’s NG, Propane or Diesel. Propane will store forever - but takes 3.5X as much fuel for the same output as diesel. Diesel stores for about a year. Obviously if you can slim down your demand for power, you can get down to air cooled range and also include gasoline. But of course gasoline stores for even less time. But as was just said - generator power is expensive!
Don't take this the wrong way... I swear I'm not a tree hugger, but is solar a possibility? Add in a couple of Tesla Powerwall battery packs so you can run off-grid.
Depending on how expensive your electric company is, you might get lucky and have a pretty quick ROI (10 years or so).
Otherwise.. I'm a big fan of Kohler. Pretty bulletproof and easy to get parts, dirt simple to service. 17kW runs my 2700sf house, AC and all, without breaking a sweat.
Depending on how expensive your electric company is, you might get lucky and have a pretty quick ROI (10 years or so).
Otherwise.. I'm a big fan of Kohler. Pretty bulletproof and easy to get parts, dirt simple to service. 17kW runs my 2700sf house, AC and all, without breaking a sweat.
When using a genset the thing most folks don't get is motor starting. Motors need 3-4 times run current to start. running motors no problem, starting them is. This is even more critical if by some chance two motors try and start at the same time.
I have a 20kw Nat Gas genset. My hot water is gas on demand, drier gas and stove also gas. All need electric to operate. Not much but they can't run without it. So my biggest load is AC. Like I said above, motor starts are the critical factor. You can damage motors with low current starts. I have enough genset that If my AC and fridge or my AC and clothes drier start together I won't lose one or the other.
Also if you go portable you can manage the load manually with the breakers. Turn AC off then water heater on, after shower, water heater off AC on. But you can't just ignore the load. You need at least 12kw to run a house central AC and that's pushing it on starting.
I have a 20kw Nat Gas genset. My hot water is gas on demand, drier gas and stove also gas. All need electric to operate. Not much but they can't run without it. So my biggest load is AC. Like I said above, motor starts are the critical factor. You can damage motors with low current starts. I have enough genset that If my AC and fridge or my AC and clothes drier start together I won't lose one or the other.
Also if you go portable you can manage the load manually with the breakers. Turn AC off then water heater on, after shower, water heater off AC on. But you can't just ignore the load. You need at least 12kw to run a house central AC and that's pushing it on starting.
Onan/Cummings
Kholer
Generac
You'll need to size your needs
Fridge,,separate freezer,, in floor radiant,,
Water heater,,any gas appliances,,heat,,gas/ wood insert? Well? City water?
Use data plates off appliances to gather info. Use amperages,,wattages.
Once spent 8 yrs installation service.
Most were LPG,,rural CO Western slope .
There were exceptions
One even got a duel fuel NG/ LPG,,as well as 40 solar panels,, inverter,transfer switch.
As a resource I recommend get a copy of Backwoods Solar catalogue.
www.backwoodssolar.com
If you need standby,,
Get a automatic transfer switch.
With a battery pack,,48v system.
Set up that gets charged continuous by your grid power,aka powerline supplier.
Set up properly,,it'll switch over automatic to battery system.
24v,,48v sytems
Also use your tax dollar based funds check resources at National Renewalable Labs
For water / well pump,,only one name
Windy Dankoff
Kholer
Generac
You'll need to size your needs
Fridge,,separate freezer,, in floor radiant,,
Water heater,,any gas appliances,,heat,,gas/ wood insert? Well? City water?
Use data plates off appliances to gather info. Use amperages,,wattages.
Once spent 8 yrs installation service.
Most were LPG,,rural CO Western slope .
There were exceptions
One even got a duel fuel NG/ LPG,,as well as 40 solar panels,, inverter,transfer switch.
As a resource I recommend get a copy of Backwoods Solar catalogue.
Backwoods Solar
Backwoods Solar Off-Grid & Grid-Tie Renewable Energy Systems For more than 40 years, Backwoods Solar has sold customized renewable energy equipment. We sell: solar panels (also called solar modules)…
www.backwoodssolar.com
If you need standby,,
Get a automatic transfer switch.
With a battery pack,,48v system.
Set up that gets charged continuous by your grid power,aka powerline supplier.
Set up properly,,it'll switch over automatic to battery system.
24v,,48v sytems
Also use your tax dollar based funds check resources at National Renewalable Labs
For water / well pump,,only one name
Windy Dankoff
Windy Dankoff - Dankoff Solar Pumps
Windy Dankoff Windy Dankoff’s career combines his technical talents with his passion for environmental preservation. In 1977, he started a wind and solar-electric business in New Mexico, to serve people living beyond the power lines. He worked solely in the private sector, where systems had to...
www.dankoffsolarpumps.com
Last edited:
Also need to balance loads in the house.
No matter how big if you microwave, fridge, coffee maker is in the same leg of the house you might overload a large genset.
It has the gross power but your dumping it all on one half of the actual generator (not the engine).
No matter how big if you microwave, fridge, coffee maker is in the same leg of the house you might overload a large genset.
It has the gross power but your dumping it all on one half of the actual generator (not the engine).
No way I'd pay $6k+ for a briggs lawn mower engine genset, even more so when you find out how inefficient the LP fuel is to run it.
I was close to buying a used 25kw diesel as we have a tank here for the tractors. 2018 was rough with Florence and Michael. Ended up going with a used Yamaha EF6300iSDE that is super quite and wired it to the panel, it will run everything but the hvac.
The welder/generator is great if you are a mobile welder, they are not very fuel efficient when used as a home generator.
I was close to buying a used 25kw diesel as we have a tank here for the tractors. 2018 was rough with Florence and Michael. Ended up going with a used Yamaha EF6300iSDE that is super quite and wired it to the panel, it will run everything but the hvac.
The welder/generator is great if you are a mobile welder, they are not very fuel efficient when used as a home generator.
Spend the money. Liquid cooled is the only way to go. Once you’re at a $10k system it’s about $1k per 5 kW more, and it’s good to overkill your needs by at least 5kW. Our Generacs are so quiet and kick over so smooth the only way to know you’ve kicked is the lights slightly dimming for a moment.
Natural gas in the city and propane away from the main grid. Practically zero maintenance and no worrying about life of fuel for either. Poor man’s (on/)off the grid without the huge $$$.
Natural gas in the city and propane away from the main grid. Practically zero maintenance and no worrying about life of fuel for either. Poor man’s (on/)off the grid without the huge $$$.
Careful with that philosophy - taken too far, you'll pay a price in fuel efficiency at lower loads. For those of us on propane, that means less time.
Generac's website does indeed have a good calculator. With a 16kW unit, I'm good to go on heating and cooling needs. I probably can't fire up the shop air compressor and welder at the same time we're running the dryer, stove, cooktop, and AC; that's a minor price to pay for run time off whatever fuel is in the propane tank when we happen to be out of town and the power goes out.
I did my entire install. The unit with one 200A transfer switch was ~$4000, then I added another 200A for the shop ($700). There is probably another $800-1000 in all the other miscellaneous material for running propane to the unit (including a larger supply line from my tank), wiring from the unit to the transfer switches, and redoing the wiring from the meter pan to the existing service disconnects (I have a Class 320 service drop to the house and shop, so everything is 2x). Figure about 40 hours of total time in the various install tasks, which saved me $3000 compared to the quoted full install from a local dealer. Everyone can decide for himself whether that's a good trade-off. It was a good project to keep my sons and I out of trouble for a few weeks.
My main regret is not making the appropriate accommodations when I redid the service entrance and propane supply during a big remodel about eight years before installing the generator. I would have saved myself from doing much of this work twice.
With a week or two behind me in the EPG field, I would suggest never even thinking about a gen-a-junk or junk-a-rak. In the size your going want once you learn more, do not buy a 2 pole unit (3600rpm) flyapart. Also never buy any whole house genset from a Mfg that sells their shit in/threw/with box stores. When you buy a genset you will either pay for it up front an never worry, or on the back side with tons of heart burn.
I’ve never had a lick of trouble In about ten years, and I have three. Definitely not the most expensive, but not made to run indefinitely either.
On one of them I have a separate tank with a bridge to the main tank as that whole house is propane, and it’s a rental property. The tank gets topped off once a month, but sometimes it’s down as low as 50% if they’re running the pool heater and there’s 10+ people per week. It would be my luck a hurricane hit when the tank’s at 50%, so I added an even bigger tank dedicated to the generator.
On one of them I have a separate tank with a bridge to the main tank as that whole house is propane, and it’s a rental property. The tank gets topped off once a month, but sometimes it’s down as low as 50% if they’re running the pool heater and there’s 10+ people per week. It would be my luck a hurricane hit when the tank’s at 50%, so I added an even bigger tank dedicated to the generator.
I manufacture diesel generators for a living, and have a 40kw unit on a trailer parked in the back yard. Not quite a tree-hugger here either.
I’m working on a solar arrangement to maintain a large battery bank. My main concern is enough solar power and battery pack to run lights, comms, microwave, freezers and refrigerators. HVAC and electric water heater are not going to be necessities if SHTF. If everything else is off, the sound of a diesel generator running can be heard for a long way, and I sure don’t want to turn myself into any more of a target than I need to. I can cover my necessities with 6kw worth of resources.
Buy ethanol free gasoline for the extra money and add stabilizer to it, and if stored in good cans, it will last 12 to 18 months without a problem.
Then just pour it into your daily drivers when it's time to rotate.
I had a generac gp8000e, and a interlock kit for my panel it allowed me to run my whole house including the well, pump, fridges,tvs etc. This allows you to safely back flow your whole panel and select circuits very cheaply. You still have to turn some stuff off but are doing it on the panel.
www.interlockkit.com
Interlock Kit & Accessories For Your Home | Generator Interlock Kit
Our Interlock Kits act like manual transfer switches for electrical panels providing safe, easy connections between homes & portable generators.
www.interlockkit.com
I’ve had a 16kw generac with the automatic transfer switch for 4 years. It has saved my ass numerous times when I’ve been out of town or the wife has been home with the kids without me. My house is a 1700sq ft ranch with a full finished basement. Everything runs on the generator. The transfer switch has a load sensing feature that will delay the A/C if there’s too much running but I haven’t had that issue. My main appliances are propane so that helps. Also all light bulbs are LED and all my wiring is modern Romex with a ground.
I have a Kohler 10Kva Kohler diesel (Kubota)genset. Came out of an offshore racing trailer with less than 300 hours. My main electrical panel is in the heated shop, house is fed by it, and the genset sits right next to it on industrial caster wheels. When power goes out, I just wheel near the overhead door and run flexible exhaust pipe under it. Sips fuel and powers heat, well and AC no problem. Best part is by being a DIY guys on cost me $800.00 bucks.
I have a Generac 22 kw generator with a whole house transfer switch that runs everything in the house. I'm fortunate to be able to use my Town's natural gas service as opposed to a tank. You might want to download the maintenance manual for the specific unit your interested in to get an idea about normal service. I perform the service on my unit which is not frequent or difficult. Best of luck with your selection.
Agreed, but if one is suffering simultaneous failures of power and gas, then we're talking about countermeasures that go well beyond a standby genset.
The Generac units are easily converted from NG to LP by flipping a lever, and someone who is normally on NG could plumb in a LP tank (better be a proper tank - not one of those 100lb portable cylinders), regulator, and selector valve. Good luck getting that arrangement signed off by the local mech inspector.
Mine is a dual fuel, NG as primary an two 250gallon LP tanks as backup to that. I have ran mine (25KW) on wood gas an she banked out at 19.2 KW still plenty for everything here. However I sold the gasifier but have everything to build another. Just wanting the Steam project finish, before jumping on the gasifier, and this time it's not for sale,...LOL
Always wanted to pick up a low hour MEP006A - 60kw.
I'm still sticking by the 7-8kwgen and the interlock. Wheel it out, fire it up, plug it into a dedicated 240 outlet and run what you want when you want. Installed less than 2k with the generator. No extension cords running through the house as you have to do with a gentran type system unless you get big enough to run your whole house.
Now we're talkin'
2006 Military Mep809a 200KW Diesel Generator Cat C12 Powered | eBay
Find many great new & used options and get the best deals for 2006 Military Mep809a 200KW Diesel Generator Cat C12 Powered at the best online prices at eBay! Free shipping for many products!
www.ebay.com
I'm in hurricane country (Florida). Semi-rural area... house is on well water. So, if we have no power, we have no water.
15 years ago, just days before hurricane Wilma, we had a full-house standby generator installed. 25kw. Runs everything, including central a/c. 500-ga propane tank underground. Automatic transfer switch. It's a Coleman, which isn't made anymore. Runs on a 2.5-liter 4-cylinder Ford engine (liquid cooled). Coleman got out of the generator business years ago, unfortunately.
Our generator maintenance dude raves about our generator (says the components are industrial grade) and is NOT a fan of Generac. I don't know which brand he recommends now (I'll ask him tomorrow, since he'll be here). But, I know he thinks Generac is shit, based on the maintenance / repairs he has to do on them.
I believe locally-stored LP is the way to go for fuel. 500-ga minimum. Utility-supplied NG can be interrupted in natural disasters.
Gasoline has two issues... it goes bad, unless you rotate it (as mentioned above). But, the bigger issue, IMO, with gasoline is that it's DANGEROUS to store in large quantities. Diesel is not as dangerous but also has storage longevity issues.
Our system was $11,000 soup-to-nuts fifteen years ago. When the power goes out during a hurricane, and it always does, it's NICE to have everything working like nothing happened.
15 years ago, just days before hurricane Wilma, we had a full-house standby generator installed. 25kw. Runs everything, including central a/c. 500-ga propane tank underground. Automatic transfer switch. It's a Coleman, which isn't made anymore. Runs on a 2.5-liter 4-cylinder Ford engine (liquid cooled). Coleman got out of the generator business years ago, unfortunately.
Our generator maintenance dude raves about our generator (says the components are industrial grade) and is NOT a fan of Generac. I don't know which brand he recommends now (I'll ask him tomorrow, since he'll be here). But, I know he thinks Generac is shit, based on the maintenance / repairs he has to do on them.
I believe locally-stored LP is the way to go for fuel. 500-ga minimum. Utility-supplied NG can be interrupted in natural disasters.
Gasoline has two issues... it goes bad, unless you rotate it (as mentioned above). But, the bigger issue, IMO, with gasoline is that it's DANGEROUS to store in large quantities. Diesel is not as dangerous but also has storage longevity issues.
Our system was $11,000 soup-to-nuts fifteen years ago. When the power goes out during a hurricane, and it always does, it's NICE to have everything working like nothing happened.
