So you've decided to investigate solar power. You have had your fill of high energy bills or maybe your area is troubled with too many energy outages beyone your control. Perhaps you want to make sure you are doing your part to keep the country "green". What ever your motivation you should consider a few factors that will affect the efficiency of a possible solar powered installation.
First what are your needs? A system for a small cottage on the lake in the northern woods will adapt very well to a small inexpensive system used only for lighting and other small electric needs where heating and cooling are not part of the system. If you are heating with a wood stove and are located in a northern climate than electric for heating and cooling will most likely need not be considered.
If your system is to be for a home in either a Northern or Southern climate, then of course air conditioning and heating will be major concerns. Usually a full flegged home will place more demands on the electrical system with all the appliances of the standard home including heating water, cooking and small electronics such as a number of television sets, radios hair dryers and other item that may not be so numerous in a summer cottage.
Your first concern of course is exactly how much sun is available year around in your area. The Southwest will of course receive more sunlight because the sun is higher in the sky in those areas. It is easy to find a number of maps describing the amount of annual expected sunlight in various areas of the world. You can investigate these to get a good estimate of how much sun you will have available for your system to convert to electricity.
Snowfall is a concern in Northern climates. Depending on your installation you may be troubled with snow accumulating on the panels which of course will have a negative effect on their output. Care should be taken when deciding where and how to install any panels in those areas with heavy snowfall.
Heavy cloud cover can be a mixed blessing. If it is heavy enough to block the sun or minimize the amount reaching the panels it could affect the operation of your system. However light clouding that filters the sun and spreads it out will help it to reach any panels that are not located in an ideal location.
Make certain that any calculations you make concerning the amount of annual sunlight available takes consideration of any smog or other air pollution you may have in your area. This would also include any adjustments necessary because of fog.
As solar power technology becomes less expensive and governments are more likely to offer grants and tax incentives, the temptation is there to enter into what can still be a rather expensive addition to your home. As with any major home improvement, do your homework. Consult experts you trust and look for recommendations from local government and other educated sources.