Advice And Reviews: Choosing A New Home Electricity Generator

An emergency electric generator can save you money if your electric power is suddenly knocked out. It's not hard to plan for your generator installation.

There are several important steps to take when choosing a new home electricity generator:

1. Installation type - permanent or temporary

2. Fuel type - usually gasoline, diesel, propane, or natural gas

3. Electric output - how much emergency power do you need?

Installation type

Cost, convenience, and available space will dictate whether you decide on a permanent or temporary installation. A permanent installation will generally cost you more, but is much easier to use. Both installation types do have a common element - the transfer switch. Regardless of which type of installation you choose, be sure to have it done by competent licensed professionals.

The Transfer Switch

The transfer switch (also called a generator panel) looks like a circuit breaker panel, but its function is to switch over certain circuits in your home (you decide which ones) so they are supplied with electricity by your generator instead of your electric utility company. Some transfer switches will switch over automatically (when the electric utility power fails), while others require someone to throw a switch manually. If someone will always be home to throw the switch, a manual switch should suffice; if you can't count on that, an automatic switch, while more expensive initially, will probably save you from having to fix frozen pipes and replace spoiled food.

Temporary Installation

For a temporary installation, you will need to have an electric receptacle installed (probably outside) near where you plan to put a portable generator. To use emergency power, you move the generator there, plug its electrical output into your receptacle, and start it up. Then you go inside to the transfer switch, and set it to use the emergency power. When the utility power comes back, you change the transfer switch setting back so utility power is used. Then shut down the generator, unplug it from the receptacle, and return it from whence it came.

With a temporary installation, you will need to periodically shut down the generator for refueling. You will also need to keep the generator in a spot that is protected from the weather, floods, etc., and make sure its exhaust is dissipated in a way that is not harmful.

Permanent Installation

Permanent installations require a bit more planning. You need to decide where to install the generator (inside or outside), what kind of fuel it should use (and how to store that fuel - see "Fuel Type" below), and how and where to vent its exhaust. The electric output from the generator should be permanently wired into the transfer switch.

Fuel type

The type of fuel you choose will depend on the type of installation.

If you are going to do a temporary installation, you will normally get a portable generator. Portable generators generally use either gasoline or diesel fuel. You need to make sure that you have enough of this fuel safely stored (in approved containers) to supply your generator for the duration of the power outage.

If you decide on a permanent installation, you should base your fuel selection on storage safety (first!) and fuel availability. If your home is heated with natural gas or propane, that is an obvious first choice for your generator fuel - the fuel feed or storage should already be in place. If you heat your home with some other fuel, diesel would probably be your best choice for your generator, since it stores more safely than gasoline.

Electric output

Your first step in deciding the size of the generator you need is for you to make a list of everything in your home that you want to have operational during a power failure. Typical items might be:

Furnace and fan(s)*

Water heater

Water pump(s) - well and/or sump*

Air conditioner(s)*


Refrigerator(s) and freezer(s)*


Small appliances*

Clothes washer/dryer*

Entertainment equipment, such as television(s), VCR(s), DVD player(s), stereo components, radio(s)

Personal Computer(s), monitor(s), printer(s)

Fax Machine(s)

Security system

Garage door opener(s)*

Power tools*

Once you've made a list, you need to get the power consumption, in watts, of each item, as well as the starting current it requires if it contains a motor (marked by a "*" above). If you can't find the power consumption in watts, you can compute it by multiplying the voltage it uses (usually either 120 or 240 volts) by the current is consumes (amps). Example: A small TV = 120 volts times 1.1 amps = 132 watts

If a device has a motor, multiply its running power by 2 or 3 to estimate its starting power. Example: A washing machine = 1100 watts running power times 2 = 2200 watts starting power.

To compute the size of the generator you'll need (watts), add all of the running power values. To that total, estimate how many motors might start at the same time and add their starting power values. Example: 3600 running watts plus 2500 starting watts = 6100 total watts. Then add 20% to 30% for a safety margin - the closer a generator's capacity is to its actual load, the hotter it will run (and the faster it will wear out), so buy as much generator as you can afford above and beyond your actual needs. Example: If your required capacity is 6100 watts, with a 25% safety margin that comes to 7625 watts, so any generator that produces at least 7625 watts will do - 8000 watts is good; 10,000 watts is better.

In addition to the proper size, you'll want to make sure the generator has an electronic regulator so its output voltage is constant (and your electronics won't get damaged). Also, check to make sure that it's relatively easy to change its oil and filters, as well as perform other required maintenance. Don't forget to test your generator every week or so. It keeps the oil distributed properly and helps uncover any problems. You might consider a yearly maintenance agreement from the people that did your installation. Also, a somewhat soundproofed enclosure is a nice thing to have.

Once you have your emergency generator installed, you can sit back and look forward to your next power outage. When you have emergency power, your home stays warm, your food stays cold, and you can even see where you're walking at night!

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