Ask Me Help Desk - Whole house automatic generator

I'm getting estimates on an automatic whole house back up generator. I'm told a 10 horsepower (or something like that) is the unit I need and I could also use a 12 but nothing smaller.

One contractor said to make sure the one I select has a governor (?). The other one said that doesn't matter.

I have no idea what, in general, I should be asking or considering.

Anyone have any ideas? I hate this homeowner stuff because I simply don't know who is over selling and who is being honest with me.

Any thoughts, including brand names - ?

See if this helps:
GENERAC Standby Power Systems
Then click Publications and Resources, the click Power and Generator Basics.

Well first you have to know your amp load, do you have electric heat, do you want to be able to run your air conditioning, do you have electric stove, are you going to use a microwave.

To power a all electric home you will need a much larger unit than you are talking about.
A governor is on most units since it allows it to slow down or speed up the RPM of the engine depending on draw needed.

But a list of all the supply needs has to be made, considering the start up amps on things like air conditioning and the fridge.

Quote:

Originally Posted by Fr_Chuck

well first you have to know your amp load, do you have electric heat, do you want to be able to run your air conditioning, do you have electric stove, are you going to use a microwave.

To power a all electric home you will need a much larger unit than you are talking about.
A governor is on most units since it allows it to slow down or speed up the RPM of the engine depending on draw needed.

but a list of all the supply needs has to be made, considering the start up amps on things like air conditioning and the fridge.

No to electric heat; yes to furnace or central air, electric stove, washer/dryer, microwave, obviously refrigerator - I want my wine to be cold if the power is out for several days, sump pump.

How do I figure out start up amps? Is there a chart somewhere?

Try these if first link didn't help:
Generator Sizing, What Do I Need?
Generator Sizing Chart - Yamaha Motor Corporation, USA
Another consideration is the hook up, one of the most Economical ways is an "Interlock KIt", it attaches to Electric Panel and will only allow Generator Breaker to Back feed into panel or Main breaker to be on at a time.

Quote:

Originally Posted by Stratmando

Try these if first link didn't help:
Generator Sizing, What Do I Need?
Generator Sizing Chart - Yamaha Motor Corporation, USA
Another consideration is the hook up, one of the most Economical ways is an "Interlock KIt", it attaches to Electric Panel and will only allow Generator Breaker to Back feed into panel or Main breaker to be on at a time.

I'm sorry but it's no help right now - I need a chart that tells me how many amps different things use.

I looked at the various sites but I just didn't understand them. I know what I have but I don't know what it takes to run them.

If the interlock panel is the panel that is separate from your fuse box and you "plug" a portable generator into it and then flip the switches and the circuits on that panel feed from the generator, I already have one - and also a portable generator.

I am now looking for a whole house automatic system.

Or am I not understanding (which is probable).

I'll come back to this thread when I have more time. I believe the units suggested for the generator are not HP, but rather KVA or Volt * Amps * 1000. VA is also the units of Watts, bu VA is necessary to use when motors have to start.

1 HP = 746 W, but it does not require 746 VA. It requires substantially more to start and it has losses.

Volts will either be 120 or 240.

The nameplate on each appliance has the information in Watts, Amps@Volts, or VA and if there isn't a VA rating on the motor we can work with HP or Horsepower.

Quote:

Originally Posted by KeepItSimpleStupid

I'll come back to this thread when I have more time. I believe the units suggested for the generator are not HP, but rather KVA or Volt * Amps * 1000. VA is also the units of Watts, bu VA is necessary to use when motors have to start.

1 HP = 746 W, but it does not require 746 VA. It requires substantially more to start and it has losses.

Volts will either be 120 or 240.

The nameplate on each appliance has the information in Watts, Amps@Volts, or VA and if there isn't a VA rating on the motor we can work with HP or Horsepower.

I think the best thing for me to do is just trust the contractor - I had no idea this would be so complicated.

But I appreciate all of the answers -

Go to this link, click on generator sizing guide.

Generac Generators | Guardian Generator | In Stock and On Sale | APElectric.com

You want to run you fridge, a couple of lights, maybe a TV, go with portable. Have to manually start and run extensions cords. You want to run A/C or furnace, maybe stove, lights and well pump go with "whole house standby". Minimum 13KVA, 20 KVA better. Price range $3500 to $5000. Automatic switching, natural gas or propane powered.

Quote:

Originally Posted by hkstroud

Go to this link, click on generator sizing guide.

Generac Generators | Guardian Generator | In Stock and On Sale | APElectric.com

You want to run you fridge, a couple of lights, maybe a TV, go with portable. Have to manually start and run extentions cords. You want to run A/C or furnace, maybe stove, lights and well pump go with "whole house standby". Minimum 13KVA, 20 KVA better. Price range $3500 to $5000. Automatic switching, natural gas or propane powered.

I already have a portable generator and the plug to the second fuse box but I have problems firing the portable generator. Last winter the power was out, I was working, my sump pump stopped and I had some water in the basement.

The posted sites don't help me because I don't know how to figure running loads and so forth.

I am looking for a whole house system, natural gas, not propane. My house is in the area of 3,000 square feet (I think).

I just want to know what to be looking for what to ask. For example, do I or do I not need a generator with a governor?

Usually you determine which loads you want backed up (critical loads) and create a sub-panel for just those loads and you size the generator accoringly.

For an entire house backup, you might switch the entire panel and do a little "load shedding". e.g. When I'm on backup power, I have no air conditioning. Covering AC on backup power is expensive. e.g. Much more capacity is needed.

It sound like you know first hand the limitations of the small portable system.

A governor on a gasoline engine is a device that limits its maximum speed or RPM when you do not have a throttle control. Your typical walk behind mower today does not have a throttle by which you control its speed. You start it and it runs at a set speed. It has a governor, a mechanical device that senses the RPM and automatically adjust the carburetor.
What the person using the term was probably referring to was a load sensing device. After starting, the generator runs at an idle speed. The load sensor senses when an electrical load is applied (you turned the light on) and opens the throttle to full speed. When the sensor no longer senses a load, the generator returns to idle speed. It's a fuel saving device. Almost all portable generators have this device. A rather simple device, an electrical coil with a mechanical linkage to the throttle control of the carburetor. I'd be a little skeptical if someone is touting this as some kind of optional feature.

The link provided gives you the typical loads for most household appliances. The first chart give the load or electrical requirements of A/C based on the size of the A/C. There is a second chart that list household appliances. Every electrical device has a normenclature tag that tells you its electrical requirements. If you look on the back of your computer you should find one. If you look on the back of your monitor you should find another. Look at your cell phone charger it's there too.

What you want to know about a generator is its running KVA or KW not its' peak. Its peak KVA or KW is what it can produce when sudden and temporary load is applied, such as when a motor starts. Here is another chart for estimating appliance loads.
Select the Right Portable Generator after a Disaster

If it helps, I have an 8500 watt generator and I can run anything I need to. Stove, refrigerator, heat and water pump are no problem. If we want to run the dryer we don't run the stove or the air conditioning. It may work but I just never took the chance. I have it hooked up with the backfeed setup. Cheapest way to go but you have to make sure you turn off your main breaker until you go back on regular utilities.

Here are some links to popular residential generators.

Each has some sort of governor, either mechanical or electronic.

Why are the contractors asking you to chose. They should be advising you.

May be best to deal with a generator vendor directly and only hire the contractor to install and connect the unit. Ask the generator vendor for a quote to install and connect your new unit, assuming your not dealing with home Depot, or a similar box store. You may be better served by using someone that deals with generators full time, once you leave a box store with a generator, they are done with you.

Generac 10 kW Automatic Standby Generator

Kohler Power: 12RESL: 12 kW: 12RESL: Residential Generators: Residential Home Generators

How to Select a Residential Home Standby Generator

Cummins Onan Natural Gas Residential Generator Comparison

I know, just what you needed is more links to review and confuse you.

My point is, and advice, is get the largest generator, rated in KW (Kilowatts), you can afford, and don't sweat whether there is a governor or not.

Most do to regulate the voltage and frequency, which is very important for many reasons.

Quote:

Originally Posted by tkrussell

Here are some links to popular residential generators.

Each has some sort of governor, either mechanical or electronic.

Why are the contractors asking you to chose. They should be advising you.

May be best to deal with a generator vendor directly and only hire the contractor to install and connect the unit. Ask the generator vendor for a quote to install and connect your new unit, assuming your not dealing with home Depot, or a similar box store. You may be better served by using someone that deals with generators full time, once you leave a box store with a generator, they are done with you.

Generac 10 kW Automatic Standby Generator

[url=http://www.kohlerpower.com/residential/detail.htm?secti Power: 12RESL: 12 kW: 12RESL: Residential Generators: Residential Home Generators[/url]

How to Select a Residential Home Standby Generator

Cummins Onan Natural Gas Residential Generator Comparison

I know, just what you needed is more links to review and confuse you.

My point is, and advice, is get the largest generator, rated in KW (Kilowatts), you can afford, and don;t sweat whether there is a governor or not.

Most do to regulate the voltage and frequency, whcih is very important for many reasons.

OK - contractor (I never looked at the big box stores) showed up, looked around, recommends a 12,000 unit. Guardian, in fact. I can connect everything I need to survive (in theory) but he said not to connect the stove or dryer because they are on 220 lines. Likewise asked if I would run the central AC in the event of a power failure or just the bedroom unit (which I run at night, I almost never run the central overnight) and I decided not to hook up for the central.

As long as I have heat, a refrigerator, a microwave, hopefully a computer, the sump pump works and the garage door goes up and down - I'm all set. The rest is just gravy.

Gave me a list of references and tomorrow I will call the BBB. Likeable enough guy, years in the business, seems to know his stuff (but I've been fooled before).

I guess the next step if I go with him is we walk around with some sort of tester and see just what is on what line - I know some but not all (I have a printout).

He works 1/2 at signing, 1/2 after Town inspects and I am 100% satisfied.

I did not know the oil has to be changed every 6 months. I didn't even know they HAD oil but he also does that on some sort of automatic plan.

So I think I'm good to go unless someone sees something that I'm missing.

He "might" buy the portable generator from me because I hate selling stuff - crazy people always show up to barter with me. The portable has only been run for 2 hours total.

Thanks everybody! Come on over to the legal board and I'll pay you back.

Well Judy...
It's been over a year... did you ever make a decision? Curious minds would like to know.