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Discussion Starter · #1 ·
Please bear with me as this question has been answered many times before I am sure. I have had 3 reputable companies come by for a Standby generator quote. I have a 125 amp main panel, 5 ton AC, 2400 SQFT house, all LED lighting, double electric oven (soon to be replaced with a gas range). All remaining major appliances are gas (furnace, cooktop, dryer, water heater). I have one installer quote me a Generac 18kW unit w/managed ATS, or a 22kW for “peace of mind” both with 200-amp ATS.
Another is quoting a Cummins 20kW with 100-amp ATS “only one with written guarantee to run 5-ton AC”,
and a 3rd is quoting a 22 kW Generac with 200 amps ATS.

The quotes are $1000’s apart hence I am seeking your advice. We don’t expect to light up the house like a Christmas tree during an outage, but being in Houston, we would want the AC to run, along with our refrigerator, some lights, computers, & TV. We have had multi-day outages twice this year and expect that to continue. What size should I go with? I am attaching a picture of my AC tag. Thanks in advance.

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i would update the service panel to a 200 amp.
most new codes require this on new construction.

and it is nice to have a 40 space box.
i prefer square D qo series.
that is the commercial version.

from there....

do a BIG inventory of your power.
pm me if you need inf for a custom meter setup so you can see your live power consumption.
you need the base line min power, and then the max power used in the summer time.

you need 25 to 50% larger gen that your load max....
that leaves you with plenty of room to start motors etc.
and that gets in to a fuel consumption thing as well..
larger gen takes more per hour in fuel....
i prefer a multi fuel gen set up so you can choose your fuel for what is available.

cat makes a nice gen set.
they are a bit more but worth the extra bucks on the mid sized larger gens.

just a bit of food for thought
 

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I recommend the liquid cooled Cummins RS25 along with an EasyStart 368 soft starter for your HCAV unit. You don't want an air cooled screamer running at 3600 RPM powering your house for long periods of time. The RS25 is much quieter and more efficient.
 

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Please bear with me as this question has been answered many times before I am sure. I have had 3 reputable companies come by for a Standby generator quote. I have a 125 amp main panel, 5 ton AC, 2400 SQFT house, all LED lighting, double electric oven (soon to be replaced with a gas range). All remaining major appliances are gas (furnace, cooktop, dryer, water heater). I have one installer quote me a Generac 18kW unit w/managed ATS, or a 22kW for “peace of mind” both with 200-amp ATS.
Another is quoting a Cummins 20kW with 100-amp ATS “only one with written guarantee to run 5-ton AC”,
and a 3rd is quoting a 22 kW Generac with 200 amps ATS.

The quotes are $1000’s apart hence I am seeking your advice. We don’t expect to light up the house like a Christmas tree during an outage, but being in Houston, we would want the AC to run, along with our refrigerator, some lights, computers, & TV. We have had multi-day outages twice this year and expect that to continue. What size should I go with? I am attaching a picture of my AC tag. Thanks in advance.

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Morning HouTx.
The size of your generator really depends on what youre looking to power continuously. I have a portable 13KW nat gas generator, have a 4300 sq foot house with a pool and i can honestly say...the one i have can pretty much start up and run all of the large devices in my house...and not be overloaded ( i also installed a power meter to watch the loads )

The last time i got a quote for a whole home generator the company wanted close to 12 grand for a " minimum" sized generator ...ithink they were quoting a general 14KW ....and 15 grand for something larger ..seem to recall it was a 20KW generac
i chose the portable route as i'm good with emergency power capability ( pulling the generator out - plugging it in) vs convenience power ( having it automatically come on)

After that last winter storm we had in texas, and a ton of my friends knowing i had a portable and had power the whole time , ive helped well over a half a dozen friends install portable generators, and 3 of them we converted to Nat gas and connected to their meter.
The best deal ive seen on a portable of a decent size is the Pulsar 12KW. thats 12KW starting, 10KW running. On Nat gas, they derate about 20% from gasoline but haven't seen one yet that couldn't run an AC, fridge, freezer and as you say - with all LED lights - the lighting load isn't even noticeable.

You will need someone to connect tup the mechanical interlock, install the generator inlet box and connect to you gas meter ( if you choose to convert from how it is sold) but it is a quarter of the price of a whole home generator...so if its emergency power you want...this might be a decent option....but if you have the money..the whole home generators are great.

DM me if you want me to send any pictures of the install and what it looks like when up and running. Heck,im in Spring Tx...so youre even welcome to come by and look at the setup yourself.

Cheers
Mac
 

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You could also get two portable inverter generators like the Honda EU7000is and convert them to also run on natural gas or propane. This is what one of our forum members did.


You'd likely still need a soft starter for your 5-ton HVAC unit though.
 

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Simple: Do NOT have as your goal to run the old technology 5 ton AC. Leave it alone in a power outage.

Install one or two small inverter heatpumps (Mitsubishi, Fujitsu, Daiken) for the 2 most used rooms, ie. master bedroom, living room or kitchen.
Cost for 12,000 BTU Mitsubishi Hyperheat (yes it both cools and heats automatically) is today around 1650.00

Any 220v inverter generator with a 30amp interlock will easily run at less than 2000 watts your house
 

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You could also get two portable inverter generators like the Honda EU7000is and convert them to also run on natural gas or propane. This is what one of our forum members did.


You'd likely still need a soft starter for your 5-ton HVAC unit though.
Would love the dual inverter option...but darn those are expensive. by the time you get 2 Honda UE7000s and the parallel kit...im pretty certain you'd be over 9 thousand dollars.

The kit for the AC is good idea though...my neighbor had kits installed on both his ACs and im certain they were a couple hundred each installed by an AC technician.
 

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Would love the dual inverter option...but darn those are expensive. by the time you get 2 Honda UE7000s and the parallel kit...im pretty certain you'd be over 9 thousand dollars.

The kit for the AC is good idea though...my neighbor had kits installed on both his ACs and im certain they were a couple hundred each installed by an AC technician.
The Honda solution is the best solution, but as you noted, it's the most expensive. There are less expensive options. Champion and Wen make larger inverters, although for some reason they are not parallel capable. Standard generators get pretty powerful. My brother in law just bought a Duromax 13 kw generator for his camp at Grand Isle. Looks like he paid about $1,500 for it. I haven't scoped it yet, but it's rated at 12% THD which isn't bad for a non-inverter.
 

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Simple: Do NOT have as your goal to run the old technology 5 ton AC. Leave it alone in a power outage.

Install one or two small inverter heatpumps (Mitsubishi, Fujitsu, Daiken) for the 2 most used rooms, ie. master bedroom, living room or kitchen.
Cost for 12,000 BTU Mitsubishi Hyperheat (yes it both cools and heats automatically) is today around 1650.00

Any 220v inverter generator with a 30amp interlock will easily run at less than 2000 watts your house
I have a 4 ton downstairs and 3 1/2 ton upstairs AC. That 13KW northstar nat gas generator i have can take them both no troubles...too bad they discontinued that one....and it can run the pool pump at the same time

The pulsar 12KW can start and run both ACs when running on gasoline but i struggle to start up the 2nd one when on nat gas....simply lose too much power when running on nat gas.

But as for someone who has run my Acs on portable power...and have helped multiple friends install their portable generators...the AC is the 1st thing we check to see if it will take the load well...and can honestly say - hasn't been a problem.

I don't think i'd shy away from running an AC. the 5 Ton is a little larger than either of my single Acs but lower combined and based on the AC label that was provided will only be pulling 25 amps when running ...leaving lots of headroom for a fridge, freezer...etc.

My primary objectives were to provide emergency power at the most reasonable price. Emergency power in Houston pretty much has to include AC....and as i didn't want to spend the money on a whole home...i found the largest reasonably priced generator i could. That pulsar is a great deal for the money but if a person wanted just a little more power...there are a couple of other options with 15KW. Westinghouse has a 15KW/12KW running thats already dual fuel...so converting to to nat gas is simple...but it doubles the price for those few thousand extra watts.

Im my mind it comes down to a couple of simple tradeoffs.
  • Are you looking for Emergency backup power...or convenience backup power. if convenience....get the whole home
  • if emergency power....How much money are you willing to spend? If you don't mind spending 3k on the generator...get the 15KW and convert to nat gas. If your budget is less...get the 12KW

anyway....just my 2 cents worth.
Cheers
 

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The Honda solution is the best solution, but as you noted, it's the most expensive. There are less expensive options. Champion and Wen make larger inverters, although for some reason they are not parallel capable. Standard generators get pretty powerful. My brother in law just bought a Duromax 13 kw generator for his camp at Grand Isle. Looks like he paid about $1,500 for it. I haven't scoped it yet, but it's rated at 12% THD which isn't bad for a non-inverter.
Northstar also carries a 7500 watt inverter that is parallel ready....but still 3500 a piece. i would love to try one out though.....55 db vs the wayyy louder standard 75 to 80 dB gen sets


Im actually a fan of Northstar generators. they have a whole range of course but their higher end products are well built.
 

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macdenewf said:
I have a 4 ton downstairs and 3 1/2 ton upstairs AC.
One of our 4 bedroom houses has 48,000 BTU's of heatpumps (cooling and heating). inverter systems. Our 3 refrigerators are 220v inverters. Our poolpump is a 220v inverter and all SWCG and Hydrochloric Acid injection systems are 220v. Our 4,500watt water heater can be toggled from 220v to 120v via a 3-way switch, effectively using only 1,125watts power. A single Honda eu7000isnan runs all of this and more using less than 3,000watts on a 95+F day and the house inside temperature is 70 F.
 

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One of our 4 bedroom houses has 48,000 BTU's of heatpumps (cooling and heating). inverter systems. Our 3 refrigerators are 220v inverters. Our poolpump is a 220v inverter and all SWCG and Hydrochloric Acid injection systems are 220v. Our 4,500watt water heater can be toggled from 220v to 120v via a 3-way switch, effectively using only 1,125watts power. A single Honda eu7000isnan runs all of this and more using less than 3,000watts on a 95+F day and the house inside temperature is 70 F.
I think if i had my time back when i built the home - i would have used heat pumps vs nat gas heating and AC cooling...but sadly not in a position to add heat pumps without seriously re working drywall to install the cassettes. but if my pool heater dies....it will be a heat pump...as id love to get cooling capability too.
Out of curiosity....ive never seen a 220 fridge in the US. Did you install them for efficiency purposes? Easy to find?
Cheers
 

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Discussion Starter · #13 ·
Thank you all for your input and suggestions. One of the 3 companies called me yesterday and reduced their quote on the Generac 22 kW by $2k so I signed up. I guess they are realizing that even with two major multi-day outages this year, and the condition of the Texas grid exposed, the market will only bear so much. In Houston most will pick an AC even if the rest of the house is in the dark! This way I will not have to pick one or the other, thanks again.....
 

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HouTX,
I'm up here NE of you a few miles, in the Big Thicket. I have researched the same stand-by generator purchase questions you pose for almost two years. I still have not pulled the trigger yet, because as Don Henley laments, "The more I know, the less I understand." "Deer in the headlights" as my research has left me, what I have gathered from monitoring the threads on this fine forum is this:

1. Paul is right: get a 200amp service if possible. Mine was forty-five years old. I just replaced mine, from the service drop down, masthead and all. Expensive, but if you are like me you'll sleep better afterwards.
2. Deweb's advice will extend the life of your generator: Limit your search to only stand-by generators that run 1800rpm, NOT 3600rpm. Dual fuel if possible.
3. Water-cooled per Deweb as well. You KNOW how hot and humid it gets here in August/September. Air cooled may be sufficient in more northern climes, but that dog ain't gonna' hunt here. Not for long anyway...
4. Of greatest importance, and an almost universally-held opinion on this forum, regardless of the sincere assurances offered by the sales reps that beat a path to your door, DO NOT PURCHASE A GENERAC. I own one. A 3600rpm air-cooled Generac. It and my tools have become intimate. As Roger Daltrey declared, We won't get fooled again!"

I offer a alternate idea. IF when you become tired and jaded of the permanent stand-by option search as I did, please give serious consideration to stepping back a bit and reconsidering what you are trying to accomplish. We both know that our first priority is preservation of our frozen food, then our thoughts IMMEDATELY turn to getting momma cool and off our back. There is more than one way to skin that cat. I too was being quoted $12-15K turnkey, but with subtle sales caveats included that protected the distributor/installer/SERVICER. I gathered enough lucidity to pause with the purchase. Blessed with time to consider, and the help of this forum, I read through those caveats well enough to see that there were potential, almost certain dark clouds on my horizon post-purchase that the sales rep had knowledge of and for which they did not want to be held liable. They had been sure to "told me so" before the purchase to protect them from liability. Does that bring to mind any of the things they told you? For me...Full Stop. So the light went off: Why not buy portable power of lesser but still sufficient capacity and use window A/C's instead of trying to provision with enough amps to overpower my central air's LRA's? Less than HALF the price. Even for the best generator brand out there.

You already have the NG knocked out. I'm thinking something in the 8-10,000 running watts range that will deliver 6500-7000watts on NG. More than enough to run what you have without the central air, especially considering all that you have that runs on NG. Buy a couple of 10-12,000Btu window units and put them in strategic windows, install momma under one, then get in the $50 Walmart blow-up pool in the back yard and ride it out. [Buy TWO pools (ask me how I know), SE Texas post-hurricane necessities.] Been there, done that. Country boy can survive. The money you save is yours to keep.

And if you decide to go through with it, most on here recommend still getting a back-up generator.
 

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Look at the Hz for those models. They are designed for use for a 50 Hz system. That tells me they are for European markets.
 

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yea on the 50 hz
they make lp fridge and freezers too!
and those LP refer truck chillers work well too!
the amish down in my area use those for stores as well as whole house ac.
 

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yup!
change out the panel and the wiring from the meter to the panel needs to be new heavy as well.
most service feeder triplex wire from the pole is good for the 200 amps these days.
but the wires from the meter socket to the service panel may be too small and needs to be 4/0 if aluminum for HD
and i do like metal conduit to the breaker panel from the meter socket or the disconnect at the meter.

oh yea new nec and fire code requires a disconnect at the meter now.
pm if you need links for those.
 

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Discussion Starter · #20 ·
I have lived in this house for 21 years without an issue with the panel. I had an old Federal Pacific panel replaced as soon as I moved in. What is the benefit of a 200 amp upgrade?
 
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