Generators

Being prepared for a power outage gives many peace of mind.  A home generator, if maintained and installed properly, can ensure you keep your lights on during an outage.
Here are some tips to help in your purchase decision as well as some helpful insights into the proper maintenance of a home generator.
Power capacity
There are many online calculators to help estimate required generator size. These assume many things and provide a reasonable guideline, but can also suggest a much larger generator than you really need. Ideally, make a list of items you will be using during an outage. Look at the label on each appliance to find its power requirement in watts or VA. Ideally you could measure the current requirement with a peak holding meter to determine maximum startup current and operating current. Startup current is important.
Many items with electric motors will have two current ratings. When they start the motor requires much higher current to begin turning than is needed after they have started to turn. A deep well pump could require over 25amps to start, but only about 6A once water is flowing. Similarly a fridge or freezer could require 15A for a very brief moment while the compressor starts but settle down to a few amps afterwards. Items such as a microwave oven or a toaster oven will usually create a steady current flow without significant peaks at startup.  If you can juggle electricity use the size of the generator can be reduced.
Generators usually have two power ratings. The lower of the numbers is usually a continuous or running power rating. When adding up all the power requirements above, this number will be the total of normal operating powers of the items being powered.
The higher number is usually labeled as surge or startup power. This is the higher of the ratings measured. It is unusual that several devices will require maximum startup current simultaneously, so consider the largest load only when determining this number.

Fuel source
Consider what might become scarce or difficult to get during an outage, especially if accompanied by bad weather. Most fuel stations will not be open if there is no electricity. A natural gas connection to fuel the generator may be ideal if available. Propane is a good option for longer run times if the home uses it already for cooking or heating. Gasoline will allow the generator to remain portable for camping or to loan to a neighbor. Gasoline generators do require stabilizer and cannot be stored more than a few months before being used. 
Engine type
Overhead valve engines typically run more efficiently and last longer than side valve engines.

Noise level
Portable generators can be noisy. If you have neighbors nearby or the noise is unbearable in your house here are some ideas.
•  Choose an operating location as far away as possible. Note that a larger gauge wire is needed to reduce voltage drop as line length increases. Reducing line loss is required to minimize power loss and to ensure maximum power is available to the house. Lights will flicker less when heavy loads are attached.
•  Change the exhaust system. Noise from the portable generator systems comes primarily from two sources, the engine block and the exhaust system. With an air cooled engine there is little you can do about block noise. Some engines can have a larger muffler attached or make other changes to the exhaust system. Merely mounting exhaust pipe vertically will noticeably reduce noise.
•  Build a noise shielding enclosure. This could be as simple as a piece of plywood to reflect sound away from the house to a separate shed to hold the generator. Design your enclosure with safety in mind. Provide adequate air circulation and ventilation to prevent heat buildup and to remove carbon monoxide.
•  Small muffler will not reduce noise level significantly. Some come with a low tone muffler which helps, but the noise level is still very high. Honda and some Chinese clones make very low noise generators in power levels up to about 3000 watts. There are techniques to help reduce the noise level.

Placement
•    During a snowstorm you will not want to trudge to an inaccessible shed to retrieve your generator.  Find a place within you home where the generator is easily accessible.

•    Keep the generator in a dry area.  You will not want it getting wet during use.

•    Avoid flammable materials with your generator.

•    Place it away from paper, brush or trees.  Generator mufflers get very hot and could cause a fire it place too close to these items.

•    Make sure the exhaust gases of the generator are not blocked.

Maintenance
•    Test the generator every 1-2 months to ensure it is working properly.  The last thing you want is a broken generator when you really need it.
•    Be sure to use a fuel stabilizer.
•    Apply a small load to the generator when testing it to maintain the health of the magnetic field.
•    Keep it clean!  This is very important to ensuring your generator will work when you want it.
    Clean oil
    Clean air
    Clean fuel