Which generator?

[6fthook]

We have an interlock kit installed in our panel with a 50a breaker and a 50a inlet box on the garage. We are undecided between 2 Generac generators:
1) 15,000 continuous watts 22,500 surge
2) 17,500 continuous watts 26,250 surge

Since both generators have a 50a receptacle and the breaker on the panel is 50a, does the 17.5k have any benefit over the 15k? Or should we save the money and go with the 15k? At low loads, would the 17.5k run more efficient?

We have a geothermal system for heat and cooling, but would turn the aux electric heat off if running on the generator.

Thanks!

 

[kd3pc]

firstly check the archives here, there are many articles on this subject...

next do a load budget and list of the items you intend to run on your 40-50Amp service. Seldom can you run the entire house, or the entire house at one time. The figure start up and run current/power.

AS to which Generac....ask the maker, there is a reason they make gennies the way they do and are expert at telling you the differences and similarities of the two you might like to purchase. Gas, Diesel, NG or propane? That will make a difference in many cases.

Unless you have natural gas on site, figure fuel storage and acquisition costs, knowing that gasoline has a limited shelf life.

 

[6fthook]

I'm asking if the 17.5k provides anymore power compared to the 15k, since in both cases it's limited by a 50a outlet on the generator and 50a breaker on the panel.

 

[Bigbandguy]

I have the 17 KW model and like it. We went with the bigger size mostly because if it switched over with both upstairs and downstairs AC units running it would be able to handle it until we turned one off. All that said... I have considered getting a good Honda portable to handle light loads and only run the monster when really needed. Even a minimal solar setup would be sufficient to run a few lights, charge phones and laptops and generally maintain civilization. That would cut down on costs and wear considerably.

 

[pattenp]

The bottle neck is 50A or about 12KW, so why get the 17KW model?

 

[theoldwizard1]

We have a geothermal system for heat and cooling, but would turn the aux electric heat off if running on the generator.

I usually recommend that anyone with a heat pump have some type of backup heat that does NOT require electricity. Propane fireplaces are perfect. Wod fireplace is also good, but much more work

Without that load, you can use a generator that is <10kW, probably <7kW.

If you are going to have a generator that is >10kW, it had better run on propane or natural gas or you are going to need to store 50 gallons of fuel nearby to cover a 1 to 2 day outage. Of course, liquid fuel goes bad over time, so you have to have a plan to rotate your stock. 10 five gallon cans. Dump one in the car once a month and refill it.

 

[6fthook]

The bottle neck is 50A or about 12KW, so why get the 17KW model?

That's exactly what I was thinking, but I'm no electrician so needed others to confirm.

Bigbandguy: How is the 17k on fuel consumption when running at low loads? Specs say 10hrs at 50% with a 16gal tank but I'm wondering how accurate that is.

theoldwizard1: We've got a wood burning insert fireplace, but haven't used it yet. Just moved in this past January. We have about 10 5gal gas cans that I use Startron stabilizer in, and usually empty them into our vehicles every 3-6 months or so.

 

[THF409]

Since the 50 amp receptacle is limited to 12,500 watts, I would go with the 15kw. generator.

 

[mshell56118]

The 50 amp breaker has a trip/time delay curve so even though continuous would only be 50amps through that plug it may the 17k may allow a larger surge and handle it better. Also remember that you have other outlets and breakers on the unit so i am guessing the 17 may have additional 15/20amp plugs that you could run an extension cord off of to a fridge to allow something else to run in the house or to run to a neighbor to keep them quiet about the unit runnning during an outage

 

[wyliesdiesels]

Are these portable generators or stationary?

Would it be possible to hardwire it instead of using a receptacle?

That way u can utilize the full power of the generator.

 

[theoldwizard1]

theoldwizard1: We've got a wood burning insert fireplace, but haven't used it yet. Just moved in this past January. We have about 10 5gal gas cans that I use Startron stabilizer in, and usually empty them into our vehicles every 3-6 months or so.

Figure out how to use the insert. Buy a couple of cords of wood and store them where they are up off the ground and dry (tarp). You do NOT want your wood pile right next to your mouse (mice and snakes).

Buy a smaller generator (5-6KW peak).

Long term, convert your cooking, water heating and clothes drying to propane. Then you can buy that monster generator and hardwire it like Wylie said.

 

[pattenp]

The 50 amp breaker has a trip/time delay curve so even though continuous would only be 50amps through that plug it may the 17k may allow a larger surge and handle it better. Also remember that you have other outlets and breakers on the unit so i am guessing the 17 may have additional 15/20amp plugs that you could run an extension cord off of to a fridge to allow something else to run in the house or to run to a neighbor to keep them quiet about the unit runnning during an outage

Very good point. I was thinking of only the 50A outlet being used to the house inlet.

 

[tyme2par4]

The 50 amp breaker has a trip/time delay curve so even though continuous would only be 50amps through that plug it may the 17k may allow a larger surge and handle it better. Also remember that you have other outlets and breakers on the unit so i am guessing the 17 may have additional 15/20amp plugs that you could run an extension cord off of to a fridge to allow something else to run in the house or to run to a neighbor to keep them quiet about the unit runnning during an outage

yes, there is some delay, but there is no way in hell you're going to get 17kW through it. That's 70A. If the breaker hasn't tripped for that, then you have a serious problem.
You aren't going to get any more power out of the 17kW unit unless there is a second power outlet (which there probably is). And then, I don't think you can feed the house with 2 separate outlets, but you could potentially power a second building.