That depends upon whether or not you are using a grid-tied system or an off-the-grid system using batteries. If you are using a grid-tied system you will lose power but could switch to a generator as a backup. If you are using an off-the-grid system or a hybrid system with batteries for storing your electricity then you won’t lose power. This is the main advantage of an off-the-grid approach.

The obvious answer of course is it depends on how much energy you use. Another big factor is whether or not you are trying to supplement your energy supply with a grid-tied system or if you are off the grid and trying to cover all of your energy needs. Probably the easiest way to look at it is to consider a range based on the amount of roof space you have available for placing the solar panels. An installation with about 14 panels would probably provide about 40-%-50% of your energy needs. If you have a large roof area you can probably fit about 24, 125 watt solar panels and cover 75%-100% of your energy needs. If your roof is not south facing or if it is partially shaded the energy output will be somewhat lower. A reputable solar installer can help you determine what is practical for your home and the amount of power you can practically generate from the space you have.

Probably. Most real estate experts currently believe that given the concerns about energy costs a solar system will significantly raise a home’s value. One source, the Appraisal Journal, states that the value of your home is increased by $20 for every $1 reduction in annual operating costs resulting from installed energy efficiency measures or energy generation systems. However, this very much depends upon the local market so you should probably confirm this with an experienced local real estate agent before making this decision if you know you are planning to sell in a relatively short period of time.

Most experts believe solar electric modules have a lifespan of at least 25 to 30 years and most manufacturers provide a warranty for this period. However, the truth is that we don’t really know for sure since most modern solar panels have not been in existence that long. Many experts believe the actual number could be much higher, possibly as much as 50 years. What is very clear is that solar modules are extremely durable and lose very little of their energy generating capacity over time. This is one of the reasons that they make sense as a long-term investment.

Yes. The solar electric system will continue to operate under fog or cloud cover but its output will be reduced. The solar electric system’s power output is relative to the “depth” of the cloud cover and how much light gets in, but typical coastal fog only reduces power output by 50%. Winter storm clouds will cause substantially greater reduction but the system will still produce energy.

Solar panels are very durable and most will last at least 25 years. Therefore, you definitely should consider the age of your roof before you install them. If your roof is more than 20 years old and in bad shape you will definitely want to consider replacing your roof before installing them. However, if your roof is in reasonably good shape go for it. In fact, adding the solar panels will actually reduce the wear and tear on your roof and make it last longer since the solar panels will block ultraviolet rays which can damage roof tiles and will help to keep snow and ice of your roof.

Learn about the tax credit for solar power provided by the Emergency Economic Stabilization Act of 2008