Once you make a commitment to moving to solar energy for your home electricity supply  there are some decisions you’ll need to make before you start to buy solar panels, or Photovoltaic (PV) cells. The first thing to decide on is the type of solar panel you want to use. Since there are several different sorts of solar panel available it’s very easy to start spending money and time going down the wrong track when you first get started. In this article I’ve focused on the three of the most important factors you’ll need to  think about to make sure you get the most out of your home solar energy system.

The three factors are:

• Technology - as there are several types of technology
• Size and Shape
• Mounting and position

Technology

Most solar panels are usually monocrystalline, polycrystalline or amorphous. What does that mean and why is it important? Basically, the different types are based on different silicon structures. Monocrystalline and polycrystalline panels are more efficient at converting solar energy into electricity. This means you can use a smaller panel to produce the same amount of power. On the other hand, monocrystalline panels are more expensive than amorphous panels. If you have plenty of space for your solar panels then the amorphous versions will save you money. It’s also worth knowing that amorphous panels are more tolerant of very hot temperatures and are slightly less affected by partial shading, although you should always keep any panels out of the shade as this can have a big effect on their efficiency.
All solar panels have long lifetimes and only degrade slightly in terms of performance over long periods of time. Most new ones include warranties that claim high performance levels, of at least 80%, after 20 years. There are even some solar cells made 50 years ago are still producing electricity today.

Size and Shape

Solar panels come in a variety of different sizes. The panels are some 2 inches or 5 cm thick. Some panels are 6 feet (2m) in length, and weigh 40lbs (18kg) but these can be tricky to handle when installing, especially when mounting on roofs, so select smaller units that are easy to handle. For example a typical panel that produces 135 watts will measure around 4 feet (1.2m) and have a more manageable weight of 20lb (9kg). You can easily connect panels together to increase power or voltage.

Mounting and Position

It’s important to mount your solar panels so they are in full sun between the hours of 10am to 3pm, when they’ll receive the most solar energy. Make sure they are not shaded by anything during this time. It’s all too easy to mount the panels where they get shaded by trees or chimneys or other structures. Even a small amount of partial shade can cause a dramatic reduction in output.The panels must be angled towards the sun on frames strong enough to withstand strong winds. Fixed mounts can be made from wood or steel and can be simple to construct.

As the sun moves across the sky the angle it strikes the solar panel will change. Whenever the angle is anything less than 90degrees the efficiency of the solar panel will reduce. The only way to overcome this is to use tracking mounts. These can be expensive but can produce 30-40% more energy by keeping your solar panels aligned with the sun.


Once you’ve decided on these three main factors you can start to build your parts list and then get down to the details of the other components you’ll need. I’ll be giving you some more information on these key components in another article in this series.