What size generator do I need?
Asked by
metadog (
381)
August 27th, 2011
I am looking at getting a generator for emergency needs. Just to get an idea of what the top end would be, how big of a generator would my house need to run the entire place? I have two junction boxes. 2 – 50 gallon hot water heaters, two heat pumps, well pump, sump pump, lights, a couple of refridgerators, electronics, etc. (dishwasher and clothes washer/dryer unnecessary).
Conversely, just to run the important stuff… sump pump, refrigerators, well pump, some lights, eectronics, etc. What size would that be?
Lastly, totally ballpark, is there a way to set up some kind of integration between the house and the generator? Or would that work? Am I looking at things the wrong way? Thanks!
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7 Answers
For all that don’t mess around and get a whole house generator, best part is it will kick in when you are out of the house. You neighbors will be envious!
You are talking about getting a stand-alone generator pack. 36kW would get most of your BIG wish list. $10K plus for professional install. Automatic disconnect ( required with auto start ) 200 AMPS.
Do you really need everything running in an emergency? Can you get by with only one heat pump. Are you willing to sacrifice a little?
If you have natural gas, a 14kW Guardian is a great unit. It costs about $8000 installed with the junction box and service contract.
I think a whole house generator with transfer switch is good for those with the money ($8–10k), don’t want to be bothered with a portable generator and those who live in areas that have an event more than once per year with long duration outages (over 24 hours).
Here is a sizing chart that you can select the items you wish covered and calculate how many kW recommendation is.
I have been in New England for many years and never needed to concern myself with it when I lived in Mass. Since I moved north to New Hampshire I have had an event at least once a year. The ice storm of 2009 left me without commercial power for 8 days.
I have a 5000 watt that can run both 120/240v. I manually supply power to specific items only (Furnace, hot water, refrigerator, some lights).
It provides peace of mind and the basics.
Response moderated (Spam)
Unless you are immensely wealthy, you won’t want to purchase a whole house generator that will run your entire setup. The two hot water heaters alone consume enough electricity to run the entire rest of your home. You can typically count on installation costing anywhere from ½ to ⅔ the equipment cost. It’s best to get a 10+ kw standby generator and have it wired into a transfer panel with adequate breakers to run your essentials. Avoid the Generac brand. I have installed many of these and they are thoroughly unreliable. Look for Kohler or Winco. Cutler Hammer puts out a less expensive unit but the quality had been diminishing over the years. The engines may be Briggs and Stratton in numerous brands. It’s the electrical components that make one brand better than another.
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