Ten questions to ask when shopping for a generator!

What goes into shopping for a generator? Here's 10 (actually 11) questions to ask yourself about what kind and what size generator to buy. Do some homework to avoid some big potential problems.


A popular pledge after Superstorm Sandy has been, “We are definitely buying a generator this time.”

Generators cost anywhere between a few hundred dollars to tens of thousands dollars. They come in many sizes and configurations and run on many different kinds of fuels. Comments from readers to last week’s column focused on generators. So let’s take a brief look at what you should consider when shopping for a generator.

Most people buy a generator to avoid long and trying power outages. Others do so, because their home or work site is either permanently or temporarily off grid.

For example, contractors building new homes that do not have electric service often use gasoline powered generators to energize the power tools and work lamps for the job site.

We can divide the world of generators into two major categories: fossil fuel-based generators versus non-fossil fuel-based generators, with the former group being the most common and well-known.

Fossil fuel generators can be further divided by whether they are portable or permanent. Portables are generally less pricey, but may be noisier and messier to deal with. 

Consider the following questions when shopping for a fossil-fuel generator, beyond the purchase price:

  1. Maintenance: What are the weekly or monthly run times required? Is lubricant required? Do air filters need regular replacement?
  2. Run time: How long can I run this generator safely before giving it a rest? While larger, permanent generators can run 24 hours a day, even these will shut themselves down periodically to cool off, be refueled or avoid lubricant or air filters issues.
  3. Fuel: What is my personal capacity or tolerance for storing this fuel (for gasoline, propane, or diesel) or regulating its pressure and volume (for piped natural gas)? What is my fuel resupply plan?  How much fuel will I need to operate my generator for 3 or 4 days?
  4. Location: Where will I store a portable generator when I don't need it and deploy it, when I do? They are heavy, so you will want to wheel them only short distances and have fuel nearby. If you are considering a permanent generator, where will you locate the concrete pad it should be set upon (to be adequately far from nearby buildings, yet accessible to fuel by pipe or tank).
  5. Emissions: What is my personal tolerance for the resulting air pollution? (At minimum, this involves staging your generator the appropriate distance from your building (Hint: 5 feet is NOT enough!).  During longer outages, how will you or neighbors react to the fumes and exhaust that may build up. Many homeowners operated their portable generators in ways that I can only
  6. Noise: What is my personal tolerance for the resulting noise? (At minimum, compare the projected decibel levels from the generators specifications with the noise ordinance levels in your town.) The biggest, most expensive natural gas generators are quieter than the lower priced portables. The most common portable gasoline generators can be deafening. 
  7. Installation procedure: What are the proper electrical connections for the generator I am considering?  Assume you will need an electrician to properly install a sub panel to identify and segregate the base load you want to energize with the generator.
  8. Permits: What local permit requirements are needed in your municipality or county? A permanent generator almost assuredly requires a building permit application and fee. (At minimum, check with your municipality about whether a building permit or separate generator application is required.)
  9. Automatic on/off: How do I turn on or off the generator? Will it come on automatically if the power goes out while I am not at home or am asleep?  Will it shut off automatically, when the power goes back on?
  10. Base load v full house load: The smaller the generator, the fewer appliances it will energize. Running a large permanent generator to energize a whole house can use a large amount of fuel. So choose the load (in kilowatt-hours) of the fixtures that are most essential to energize in your home or office. It makes sense to scale the generator to that essential base load, to avoid buying more generator than in practical. (See final point below!)
  11. Return on investment: How do I feel about spending money to buy a generator that I will only use in the emergency of a power outage?  In short, the any money I spend on that generator, and the electrician, and on any permits or concrete pads or wiring or gas piping will only pay off during the hours that it operates.
  12. Backfeeding the grid: Am I sure that when my generator is on, I am NOT sending energy back through my service panel out to the power lines on the street?  In other words, did I remember to open (OFF position) the main swich on my service panel BEFORE I started the generator. If not, I may be backfeeing the power line in the street and potentially setting up an electrical surge in the nearest transformer that will rudely surprise the line man coming to fix my outage, who thought the line was de-energized. 

New York State offers no incentives whatsoever for buying emergency fossil fuel generators. Any shekels you invest in such equipment may only ever come back to as peace of mind by avoiding the loss of a refrigerator of food and having an operable furnace.

Next week, we'll take a look at non-fossil fuel generators. There has been some great recent breakthroughs, particularly in photovoltaic (solar panel) controls for battery storage systems. 


Leo Wiegman November 30, 2012 at 06:41 PM
Dear Susan: Absolutely, solar panels can definitely charge battery banks that wil keep your home's vital appliances (refrigerator, oil burner, a phone charger and a few lights) running at night. In fact, a solar system with a smart brain and modest battery bank will pay for itself within 9 years, while sending you electricity every time the sun comes up. I am going to write about this solar option for the next column. Thanks for the feedback.
Leo Wiegman December 01, 2012 at 11:56 PM
Here is information about a back up solar generator alternative that never needs fuel and has no moving parts: http://ossining.patch.com/blog_posts/what-if-your-generator-never-needed-fuel
Wayne Tompson June 11, 2013 at 04:55 AM
Thanks Leo for the great help. I found this one also a they sell Generators and portable.. http://www.mygenerator.com.au
Leo Wiegman July 01, 2013 at 05:40 PM
Wayne: That's an interesting site in Australia.


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