Standby generator: Power whole house?

[reader2580]

Does anyone have a standby generator that powers the whole house? I'm looking at getting an 11 KW generator so I can power most everything in my including my central air conditioner. (Previous house with 8KW generator only had maybe six circuits powered, but it also powered central air.)

It is a pain to only have power to some things, but not others. I would like to just get a 200 amp transfer switch to run everything through, but the installation costs add up with new run to the meter and all that. Another option is to get a new panel with transfer switch built in to save on wiring, but only 18 of 28 breaker slots could have generator power.

 

[LS6 Tommy]

How big is the A/C? 8k is only good to about 2 tons, and that's with everything else off. I helped with a 10k at my father in law's house and 20k at my cousin's house. They both love not having to worry about things when they're not home. I'd do one for my house in a heartbeat if we had a gas main on the street.


Tommy

 

[reader2580]

My central A/C only has a 20 amp 240 volt circuit running to it. My previous house also only had a 20 amp 240 volt circuit running to the central A/C. Newer central air conditioners take less power than older units.

My previous house I had an 8KW generator and it ran the central A/C, garage door opener, one circuit of lights, refrigerator, furnace, sump pump, smoke alarms, and one outlet circuit just fine. I am looking at doing 11/12KW for current house to be able to run pretty much everything.

 

[theoldwizard1]

Does anyone have a standby generator that powers the whole house? I'm looking at getting an 11 KW generator so I can power most everything in my including my central air conditioner. (Previous house with 8KW generator only had maybe six circuits powered, but it also powered central air.)

It is a pain to only have power to some things, but not others. I would like to just get a 200 amp transfer switch to run everything through, but the installation costs add up with new run to the meter and all that. Another option is to get a new panel with transfer switch built in to save on wiring, but only 18 of 28 breaker slots could have generator power.

You are confusing a couple of different things. The six circuit limit is sort of an "artificial" limit made by the company who built that box.

Automatic transfer of the whole house is expensive, but convenient. Most modern auto tranfer switches have "load shedding" so that the A/C (or water heater) will be dropped if there is too many other things loading it down.

IMHO, if you are willing to make a few decisions on you own as to which things you want to power during an outage, you can save a lot of money. A breaker panel with a "generator interlocK" will let you run your whole house with minimal additional wiring. You may have to decide what to turn off if the load is too much for the generator (water heater, electric stove, electric clothes dryer, etc).

8kw should be enough to run an "average" 3 bedroom house without A/C. Add in A/C and ...

 

[theoldwizard1]

My central A/C only has a 20 amp 240 volt circuit running to it. My previous house also only had a 20 amp 240 volt circuit running to the central A/C. Newer central air conditioners take less power than older units.

That is an "average" amount of power. "Start up" power could be 2 or 3 times as much for a split second. Some A/C units will spec a LRA (locked rotor current) which is what you need to know. This could easily be >10KW.

 

[reader2580]

You are confusing a couple of different things. The six circuit limit is sort of an "artificial" limit made by the company who built that box.

Six circuits is because that is what I chose to power with the generator. I could have added more. I did not have one of those transfer switches with a sub panel built in.

The generator came with a 100 or 200 amp automatic transfer switch. I added my own sub panel for the stuff I wanted the generator to power. The sub panel still had more slots available.

 

[Pwrgeek]

A 7500 harbor freight unit ran my whole house (2ACs, fridge, tv, and well). With AC units it is all about starting them as running they actually don't draw that much (my 3 ton units each draw 14 amps running). That being said one of my upgrades last year was to put in a Generac 22kW unit with auto transfer. We have some of the worst power reliability I've seen (I actually work for a different electric utility so I know) and have now had that unit save us from about two days worth of outage. The main reason I went to the auto transfer unit is we now have an electric gate. I didn't want the wife coming home during an outage and having to climb the fence. Also it is nice to know the fridge and freezers are fine when we are gone. The Generac transfer switch came with units (which I ended up not needing) that you can put on any large electric load to keep it from overloading the generator.


Sent from my iPhone using Tapatalk

 

[Wes J]

You're in Minneapolis and need air conditioning so bad you can't even live without it during a power outage? Amazing. I'm 400 miles further south than you and I almost never use mine.

 

[reader2580]

I'm trying to figure out what in a three bedroom house is going to use 8,000 watts of power without central air? That is 60+ amps at 120 volt, or 30+ amps at 240 volt. I'm assuming a gas water heater and gas heat. You probably wouldn't turn on an electric stove if the power is out.

8,000 watts continuous would mean you would be spending upwards of a dollar an hour for electricity when not running on generator. My highest electric bill in the past year was $3 a day when I ran central air for the whole month. (12 cents a KWH for electricity.)

My last 8KW generator ran my central air just fine. The biggest loads other than central air were my furnace blower and refrigerator. Generators can handle a surge of power providing it doesn't last long. The breaker on the generator would have blown if it was overloaded for too long.

 

[turbowoodworker]

22kW here. Auto transfer, self tests weekly. 15 second delay. Pretty happy so far.

 

[reader2580]

Turbowoodworker, do you run the breaker panel through your transfer switch, or do you have a sub panel for things that will run on generator only?

 

[Spoiled Bradt]

This is one of the few times I say call a company.Not electric in general. Just power generation. You don't want overkill and surely don't want not enough. Technology has changed greatly since mine were installed around 2000.
Get the pros so you have support and knowledge of what you "need". Local power companies have many do-and don'ts too.

 

[reader2580]

You're in Minneapolis and need air conditioning so bad you can't even live without it during a power outage? Amazing. I'm 400 miles further south than you and I almost never use mine.

My body is extremely sensitive to high heat with humidity so yes I like to have air conditioning. I have had heat exhaustion at least three times even while drinking lots of water and Gatorade to stay hydrated. It can get very humid in the summer in Minneapolis.

My body tolerates dry heat just fine. I was in 107 degree desert heat a few years back and it felt better than 85 and humid at home.

 

[86turbodsl]

I have an emerson whole house transfer switch. 200A. I have 400A service, split 200 off directly at the meter to the shop, and the other 200 feeds the transfer switch. Nema 1 rated, it's in the basement right next to the main and subpanels. As i recall it was about 1200 dollars and i installed it myself when i wired my house. I haven't bought a genset yet, but i'll probably buy a 20kw diesel when i do.

 

[simpler=better]

I hear you on the humidity, it's like soup out here in the summer. Energy independance is really important to me.

As the wizard said, an interlock kit is the easiest & cheapest way. You can get up to a 125A breaker (At least with a SD panel)

My setup:

I run a diesel 5KW/8KW unit from the 80s on an interlock with 6ga THHN and a 50A breaker. I've used it to run an Arc welder before, a little tricky to start but it was a champ after the initial strike.

I like the manual interlock:
-It's simple
-I'm reminded to check the oil before starting the generator.
-I like to warm the generator up before loading it down
-Easily isolate power hog circuits
-When the power goes out and I'm not home, it's not wasting fuel.

I like the diesel:
-My fuel stash isn't explosive
-Can be stored for years
-1800rpm is nicer to listen to
-No carbeurators to mess with
-No spark plugs to replace

Here's a few pics of my setup:

Future plans:
-Build a shed for the generator
-Add automatic float chargers to the batteries

 

[Rokjhn]

I installed a Kohler 48KW to power up both AC units, Pool, Hot Tub, Fridges, Freezers, Neighbors coffee pot, and etc... with automatic transfer switch. Runs on LP Gas. I live along the Texas Gulf Coast at the end of the power lines and lost power for 10 days during Hurricane Ike in 2008. Not going to happen again!

 

[gungatim]

I run my whole house on a 6k watt portable generator without problem. I haven't run the AC but we have 2 fridges and a freezer, the furnace, well, lights, tv, and general appliances all running at once without any problem. I don't use a switch with limited number of breakers, my entire box is powered, we just are judicious with what we have on, meaning if the wife has to do laundry, i'll switch off the shop and garage to make sure the extra fridge and freezer don't happen to kick on at the same time as the washer...the amount of work and monitoring for a setup is directly proportional to how much you want to pay. around here, it's not uncommon to spend $8k-10k for automatic systems with large oversized generators. I'm into my setup for<$500...YMMV

 

[Bigbandguy]

17 KW here. We set up the generator panel to run one AC unit at a time since we rarely use the 2nd floor during the day. When we bought it we included the electric stove, now converted to gas. The unit is a Generac with automatic transfer. One thing to keep an eye on is the float charger that comes with it. If the run from the panel to the Generator is fairly long there can be enough line loss that the battery does not charge well. We finally fixed that with a run of #14 for the float charger instead of the doorbell size wire that came with it. Thus far it has been cheap insurance against power failure as we have only needed it a couple of times in five years. Before we moved here the neighborhood was out for two weeks after a hurricane so we decided early on that we would skip a vacation and get it done. No regrets on that.

 

[ctfjr]

fwiw, my son & I picked up government surplus diesel gensets at a Ft Meade (MD) auction. The model is MEP-003A. They are rated by the government to be 10kw. A little searching on youtube and you can probably find the guy that is running his at 14kw for an hour. We were both lucky (and careful) that we got really good units. Mine had been completely refurbed and put on a new trailer about 3 years before we bought them and only had 3 hours on the clock. My son actually inspected the 25 or so of them that were being auctioned & we picked out 6 to bid on. He must have over 500 hours on his (lives in MD) while I only have <50. Most of that is monthly starting. I found a 400 amp brandy new manual xfer switch on ebay & got it for $200 (incl shipping). I did not want auto xfer.
I have several ac split systems in the house & we have run 3 of them (3 & 2 2 -1/2 ton) at the same time. All our breakers are powered when I switch over. You might want to consider what kind of motor is hanging on that genset you buy. Nat or LP gas powered are super convenient. Gasoline, not so much. The diesel has considerably more torque to start those motor loads and I heat the house with #2 fuel.
The company I work for sells Honeywell brand (Generac) gensets. A 10kw nat gas unit weighs 300lbs. My diesel weighs 1300.
It wasn't such a big project for me to do the install. I had an electrician do the tie in between the 400A panel & the xfer switch. The rest I did.

 

[simpler=better]

fwiw, my son & I picked up government surplus diesel gensets at a Ft Meade (MD) auction. The model is MEP-003A. They are rated by the government to be 10kw. A little searching on youtube and you can probably find the guy that is running his at 14kw for an hour. We were both lucky (and careful) that we got really good units. Mine had been completely refurbed and put on a new trailer about 3 years before we bought them and only had 3 hours on the clock. My son actually inspected the 25 or so of them that were being auctioned & we picked out 6 to bid on. He must have over 500 hours on his (lives in MD) while I only have <50. Most of that is monthly starting. I found a 400 amp brandy new manual xfer switch on ebay & got it for $200 (incl shipping). I did not want auto xfer.
I have several ac split systems in the house & we have run 3 of them (3 & 2 2 -1/2 ton) at the same time. All our breakers are powered when I switch over. You might want to consider what kind of motor is hanging on that genset you buy. Nat or LP gas powered are super convenient. Gasoline, not so much. The diesel has considerably more torque to start those motor loads and I heat the house with #2 fuel.
The company I work for sells Honeywell brand (Generac) gensets. A 10kw nat gas unit weighs 300lbs. My diesel weighs 1300.
It wasn't such a big project for me to do the install. I had an electrician do the tie in between the 400A panel & the xfer switch. The rest I did.

The MEP002 and 003 are great! The wiring is weird, but the 200 page tech manual spells it all out if you take the time to read it

 

[ishiboo]

I have a 2400-square foot brick 2-story. My 7kw HF generator powers the entire house save for the AC, dryer, and now electric stove.

I have a 20KW PTO generator but haven't needed to use it yet. Would rather put hours on the HF (and the backup Briggs) than the tractor.

I much prefer a whole house transfer too. I have an interlocked feed in the main panel, though the eventual plan is to feed the house from the barn (eliminating one meter) and have all backup power automatically come on and switched at the barn.

 

[reader2580]

The only generators I am considering are automatic with natural gas engines. I have natural gas service at my house. If a disaster knocks out both electricity and natural gas it would probably be a pretty big disaster.

I also have a motorhome with a diesel generator, but it only produces 120 volts so it won't work for my well. If it did 240 volt I could just manually start it and hook it to the house when power failed. 130 gallons of diesel will a week and a half.

I am considering a used 15KW Generac someone local is selling cheap. He will demo it before disconnecting it. He is getting a larger generator so he is keeping the transfer switch. I think I would have just over $2,000 in the project including transfer switch.

 

[theoldwizard1]

The only generators I am considering are automatic with natural gas engines. I have natural gas service at my house. If a disaster knocks out both electricity and natural gas it would probably be a pretty big disaster.
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I am considering a used 15KW Generac someone local is selling cheap. He will demo it before disconnecting it. He is getting a larger generator so he is keeping the transfer switch. I think I would have just over $2,000 in the project including transfer switch.

Make sure to get it installed by an experienced technician.

 

[4 FN 27]

When I built my house back in 2009 we installed an Onan NG 40KW and Switch Gear. All 3 Panels, 2 for the house and 1 for the "Off Peak" Geo Systems. Works great when the power does go down. We load tested it with the 3 Geo Forced Air Units and the In-floor unit and it holds. But I think if we get in a long term power outage I'll opt for shutting down the Geo Force Air Unit that does the second story and the unit that takes care of the Bonus Room above the garage.

I use to work at a place about 2 miles south of our house and when the power would go down it was usually for 1-2 full days. Since 2009 we have lost power for about an hour once. But I sleep better knowing we have power during an outage since we have a Well and Septic with a Lift Station. Makes for a happy Wife.

 

[reader2580]

Make sure to get it installed by an experienced technician.

I installed the generator at my previous house and I have no doubt I can do it again. I did hire someone for the natural gas.

I am probably going to skip the $1500 generator I looked at today. I really liked the liquid cooled engine, but it has a meter for frequency and it was jumping all over from 51 hertz up to 64 hertz. It didn't matter if the generator had a load or not.

The guy said he is upgrading to a larger unit. He had the new generator in the garage and it is only 1000 watts larger. I suspect there is a reason besides going bigger for replacing the generator as who only goes from 15KW to 16KW if they need a larger unit?

 

[fastjohnny]

I installed the generator at my previous house and I have no doubt I can do it again. I did hire someone for the natural gas.

I am probably going to skip the $1500 generator I looked at today. I really liked the liquid cooled engine, but it has a meter for frequency and it was jumping all over from 51 hertz up to 64 hertz. It didn't matter if the generator had a load or not.

The guy said he is upgrading to a larger unit. He had the new generator in the garage and it is only 1000 watts larger. I suspect there is a reason besides going bigger for replacing the generator as who only goes from 15KW to 16KW if they need a larger unit?

Good call. Sounds sketchy..

IMO, a few extra KW is not going to be that costly up front, I'd go as big as it takes to run everything.

My system is like ishiboo's, honda 6500w that sits right inside from the panel, wheel it out, plug it in, lights back on, then hook up the tractor to the 25kw/50kw surge PTO genny and then everything runs full tilt.

 

[theoldwizard1]

I installed the generator at my previous house and I have no doubt I can do it again.

The generator install is easy.

Installing the automatic transfer switch CAN be difficult and I would not recommend it for for any non-professional. Don't forget the control panel.

 

[reader2580]

The generator install is easy.

Installing the automatic transfer switch CAN be difficult and I would not recommend it for for any non-professional. Don't forget the control panel.

My previous house was custom built for me. My father and I wired the entire house (with permits) ourselves including the transfer switch. They really aren't that hard to wire up. AC in from the service panel, AC in from the generator, AC out to a sub panel or whatever, and a low voltage line out to the generator for starting it.

I am leaning towards just putting in a transfer switch and a sub panel instead of trying to power the whole house. It becomes quite difficult to route the wire required for 200 amps to/from the transfer switch.

 

[theoldwizard1]

I am leaning towards just putting in a transfer switch and a sub panel instead of trying to power the whole house. It becomes quite difficult to route the wire required for 200 amps to/from the transfer switch.

Modern transfer switches sit IN BETWEEN the POCO feed and your panel. There is no separate set of individual breakers. When the generator comes on, the POCO feed is disconnected and the generator feed is connected. The only new wire is from the generator to the switch and feed from the switch to the breaker panel.

As I mentioned, some of these "whole house automated transfer switches" are designed to feed "heavy" loads (A/C, water heater, stove, clothes dryer. etc) directly (NOT from your existing breaker panel). This allows the controller to either delay the startup of these loads until conditions have stabilize or not turn them on at all if there is not enough power available.


Using a generator "interlock" kit will accomplish the same thing, except manually and at a fraction of the cost.

You need to do more research.

 

[Pwrgeek]

Modern transfer switches sit IN BETWEEN the POCO feed and your panel. There is no separate set of individual breakers. When the generator comes on, the POCO feed is disconnected and the generator feed is connected. The only new wire is from the generator to the switch and feed from the switch to the breaker panel.



As I mentioned, some of these "whole house automated transfer switches" are designed to feed "heavy" loads (A/C, water heater, stove, clothes dryer. etc) directly (NOT from your existing breaker panel). This allows the controller to either delay the startup of these loads until conditions have stabilize or not turn them on at all if there is not enough power available.





Using a generator "interlock" kit will accomplish the same thing, except manually and at a fraction of the cost.



You need to do more research.

There is no reason you can't place a transfer switch between the main and a sub instead of between the service and main. Done all the time. Works fine. I'd prefer a whole house system (with an appropriately sized genset in fact that's what I have) but there is no reason you couldn't do it like this to save on cost.

 

[reader2580]

What a lot of transfer switches do for air conditioners is turn them off via the control wires versus actually cutting the power. They just interrupt signal from thermostat.

 

[larry4406]

What a lot of transfer switches do for air conditioners is turn them off via the control wires versus actually cutting the power. They just interrupt signal from thermostat.

Yes - I think Generac calls this a "load shedding module" or something to that effect.

 

[tfalk]

We had a generac 18kw whole house generator installed 2 years ago with an automatic transfer switch for the entire house. Comes on once a week for 3 minutes. Ended up actually using it for the first time last week when the transformer across the street gave up the ghost. Also had 2 new high efficiency hvac units installed last year.

A couple of months ago, I installed a Brultech energy monitor so we could see exactly how much power we were using at any time. On christmas, with the oven and it seemed like every light in the house on plus the warm temps, SHMBO had both a/c units running... Monitor showed we never went over 9KW at any time that day so I think it's safe to say the 18KW is a bit overkill. It's wired with load shedding modules on both A/C units and a third that makes sure the heat pump for the pool never comes on while the generator is running. We did not add load shedding modules to the air compressor or my 4 post lift. Even so, the lift is manual control and I don't think the air compressor would be a problem.

My understanding from the electrician who installed it is once the generator comes on, it will wait 5 minutes. If there is capacity at that point, it will allow the downstairs A/C unit to come on if it calls for it. After another 5 minutes, if there is still capacity, it will allow the upstairs A/C unit to kick in....

 

[woodzy]

I have a 16k with a 200 transfer switch. Installed it during the house build. Plenty of power but wanted the 16k as it has an aluminum housing. Been 1.5 years and have not needed it yet. Runs every week just to test itself. Just another insurance policy.

 

[tfalk]

Something else to consider regarding the cost of installing a whole house... In our case, everything is gas... 2 furnaces, dryer, stove, generator. Our utility (PSEG) will upgrade 1 size on meter for free... yeah, we were over that... 2 size upgrade was $1400. Said we should be good to half a million btu's now...

 

[QwikKotaTx]

I installed a Kohler 48KW to power up both AC units, Pool, Hot Tub, Fridges, Freezers, Neighbors coffee pot, and etc... with automatic transfer switch. Runs on LP Gas. I live along the Texas Gulf Coast at the end of the power lines and lost power for 10 days during Hurricane Ike in 2008. Not going to happen again!

In Katy?? I lived in La Porte then and was only without power for 4 days. I have a small genny to keep the fridge alive and run a fan at night. I also have a small window unit in case it's too hot. I just can't see going to the expense of a whole house generator with as reliable as our power grid is and how expensive the unit and install could be. $15k I believe and don't get me started on another item to maintain.

 

[wyliesdiesels]

48Kw? Thats way overkill for a residence. I bet u dont even have a 100a load on the generator with all of that.

 

[chrispyny]

I won an auction for an air cooled mep-002a military diesel genset with 89 hours on it 2 years ago. Mep means Mobile Electric Plant. It was highly robust, capable of around 8,000 watts. It was awesome but loud.

I won an auction on govplanet for an mep-802a with 22 hours late last summer. Current power generation for our military. It has a onan licensed lister petter engine, sips 1/2 gal an hour of diesel at full load of rated 6300 watts but will do more. The military underrates its gensets. . The best part is it is liquid cooled and quietly purrs along while running.
I ran a 30 amp power inlet box next to the panel on the outside of my house. Installed an interlock kit on a 30 amp panel to backfeed to my whole house. Made a generator pad from blue stone and pressure treated lumber, and installed a power outlet box on the side of the genset. Also installed a 24v solar panel to keep the batteries topped off.

I wanted to add, when the **** hits the fan, i don't want to burn through 4 gallons an hour of diesel just to say i have 30kw of juice at my disposal.
My home has a ng hot water boiler with hot water baseboard for heat, ng hot water boiler for domestic hot water, and i have a jotul c450 wood stove i installed in 2013 for back up heat. I don't need eleventeen thousand watts of juice. Sometimes less is more.

I read on another site that one guy had a whole house ng generator he ran for a couple weeks during an outtage due to a hurricane down south. The next month he got a natural gas bill from his energy company for over $900 or something. Less is more.
And no one needs a transfer switch of any kind. My interlock kit lets me power my whole house without designating circuits or purchasing thousand dollar transfer switches to ensure enough circuits have juice during an outtage.

 

[reader2580]

No, you don't need an automatic transfer switch, but they are nice. I bought one the other day on EBay for $300 shipped. It is being sold as surplus, but it new with 30 day warranty.

 

[Stevie-Ray]

I run my whole house on a 6k watt portable generator without problem. I haven't run the AC but we have 2 fridges and a freezer, the furnace, well, lights, tv, and general appliances all running at once without any problem. I don't use a switch with limited number of breakers, my entire box is powered, we just are judicious with what we have on, meaning if the wife has to do laundry, i'll switch off the shop and garage to make sure the extra fridge and freezer don't happen to kick on at the same time as the washer...the amount of work and monitoring for a setup is directly proportional to how much you want to pay. around here, it's not uncommon to spend $8k-10k for automatic systems with large oversized generators. I'm into my setup for<$500...YMMV

I do the same with a Coleman 5KW. (6250W surge) Only time I even see lights dim is when the pump kicks on, and now that I am slowly replacing lights with LEDs, that doesn't happen much. We won't use AC, of course, but we generally don't use it more than a few times in the summers anyway. Before last year, when I got the interlock, I was just plugging in necessities and relying on a gas fireplace to keep us warm enough to make it through several days of below freezing weather. The fireplace will save your life, but it's not very good at keeping a large house completely warm. Now it only comes on when expecting to get power back in hours rather than days. The interlock paid for itself already, in the 3 times we've used it, IMO, including last Christmas. (3 days) The convenience is awesome to actually have your furnace and pump like normal people. Uses less than a half gallon of gas an hour. (12 hour run time-5 gal tank) I actually asked the wife about a standby generator, but she didn't want to spend the money on something we don't actually need yet. We'll save that for when I can't do this anymore.