COMPARISON OF PORTABLE AND STATIONARY GENERATORS FOR HOME STANDBY USE

Most people can not live comfortably without continuous, stable electrical power. Thousands of people purchase small electric generator sets to protect themselves, their families and their businesses in the likely event of power failures. Here are some basic tips.

Portable vs. Stationary – Let’s Compare Convenience and Cost

Although a portable generator can be manhandled, with an average weight of 250-300 lbs, you can't call them lightweight. If you purchase one, make sure it comes with a set of wheels (sometimes these are optional). Portables are universally fueled with gasoline, a fuel that requires safe storage and extra care in handling. Some portables have very small fuel tanks, so they need refueling every half hour or so. Given the choice, go for a portable generator with at least a 5 gal tank. And don’t forget that gasoline doesn’t store very well and will get gummy over time.

Portable generator owners usually employ a series of extension cords to connect the generator to specific items in their house, such as a refrigerator, lights, computer, and TV. Although this system works, it is most practical for outages of a short duration. Most portable generators are “rope started”, like lawnmowers. If your wife, teenager or elderly relative will be using the generator (not recommended) you should go for an electric start option, if available. As you can see, there is essentially nothing automatic about a portable generator.

On the other hand, a stationary (automatic) generator averages $5,972 - but look at the differences!

Stationary generators start at about 500 lbs and are designed with a weather protective housing that mounts outdoors on a level surface. Fuel is continuously supplied via your natural gas service or propane tank, whichever you choose. Your electrician will “hard wire” the electrical cables to your distribution panel (no extension cords to deal with here).

Starting is fully automatic. In fact, it can take just 15-30 seconds from the beginning of the power outage until the generator is completely up and running. This type of generator employs an automatic transfer switch which monitors the incoming power and switches the generator on and off as needed.

How do you know which size generator you need?

Determining the size of your generator is all important. Electric power is measured in watts and 1,000 watts is called a kilowatt. All electrical appliances in your home have an electrical tag or label on them, which states the wattage. Sometimes the tag shows only the voltage and amperage. If this is the case, multiply the voltage by the amperage to get the wattage. Example: say the electrical label on the back of your toaster reads 120 volts and 10 amps. To get the wattage, 120 V x 10 A = 1200 watts. Since 1000 watts = one kilowatt, the load can also be considered 1.2KW.

Add up the wattages of the loads that you consider essential, then multiply by 75% to account for the fact that everything will not be on at the same time. It’s a good idea to discuss your loads with an electrician - he can also determine or verify your loads easily and quickly using his ammeter.

Portable generators usually range from 3-15KW but you can only get 1/2 the power out of each large outlet unless the generator has a full power plug (which is rare). Stationary generators are in the 7-40KW or larger range. The larger sizes are normally needed only if you have heavy electrical loads like a large well pump or a central air conditioner. The average sized generator for a normal home (without a central air conditioner) is in the 10-12KW range.

For additional information about generators look at About Generators on our website.