With recent Hurricane Sandy, I had several friends calling looking for generators for their homes as the storm was approaching. By that time it was too late as most people found out.
The most important question you need to consider when looking into a generator is: “What do you want to operate if the power goes out?” Some of the things you need to consider when selecting a generator are Heat, Water Heater, Water supply if on a well system, Sump Pump, Range, Refrigerator, Freezer, Washer, Dryer and Lights. Of course the more you want to operate, the size and cost of the generator will increase.
Most generators being scooped up off the shelves at the home improvement stores are relatively small in wattage and will only operate some lights and maybe a refrigerator. These types of generators will not operate multiple or high wattage appliances such as a Range or Water Heater and certainly will not operate a heating system if the outage would happen in colder weather. The need for a generator can vary with the area you live in playing a key role. Overhead power lines are often affected in a storm where there are trees around. Some areas are just prone to outages during storms of any kind.
Remember to plan well in advance while the weather is nice and before a storm leaves you in the dark and cold.