How to choose Solar Electric Panels

Space and orientation are two factors dictating your choice of panel.

Installing solar electric panels, sometimes also known as photovoltaic" or PV panels, reduces your home's energy bills by converting unused roof or yard space to electricity production. Whether you want to undertake the installation yourself or wish to employ a contractor instead, drawing up a plan for your home solar system is a necessary step. If you are building the system yourself, you need that plan to choose your panels and build the system. If you pay a contractor to do the work for you, drawing up the plan and choosing the panels gives you a clear idea of what to expect.

Difficulty:

Easy

Instructions

Things You'll Need

• Pencil
• Paper
• Calculator
• Tape measure
• Solar panel retail catalog(s) (optional)

1. Factor other home repair and maintenance projects for the middle-term future into your solar panel plans, since this might impact the type of panel you choose. Silicon-based panels are the most effective, but if you need to re-shingle your roof in the near future, choosing thin-film solar shingles enable you to kill two birds with one stone.

2. Establish the power needs your solar panels must meet in terms of watts by listing what devices the panels will power and determining what the total daily power demand for each device is. In the kitchen, a refrigerator typically consumes 725 watts per hour, 24 hours a day, for a total of 17.4 kilowatt-hours. A coffeemaker, however, might consume 1,000 watts, but only see 15 or 20 minutes worth of use for a total of .250 to .333 kwh. Calculate for every appliance, electrical device and light fixture in the house, and add the results.

3. Determine where you want to install your solar panels. In the United States, the sun follows a southward path, so for the best results your panels must be in a shade-free area facing south. Only part of your roof fits this description, and you may or may not have suitable yard space for the panels.

4. Calculate the dimensions of your solar panel area by measuring the length and width.

5. Research available solar panel types through catalogs and online retailers, and sketch on paper how your solar panel system might look with different panels and different configurations. Two rows of mid-sized panels might prove a better fit and produce more power than one row of large panels.

6. Pick a panel model based on your configuration sketching from Step 5 and determine that panel array's output. Each panel has a power output statistic in watts, so multiply this by the number of panels in the array. Then multiply that sum by the average yearly amount of full daylight in your area (usually five or six hours). An array with 16 10-watt panels produces 160 watts per hour, for a daily average of 960 watts, in sunny parts of the United States.

7. Compare the results from Step 6 to your power needs from Step 3. If your sketched system and chosen panels fail to meet your goals, you must either scale back your goals, choose a different panel and start over, or choose another place for your solar system and start over.

Tips & Warnings

• The federal government and some state governments offer tax incentives for home solar power systems. The terms of these incentives may also influence your choice of panel.

References

• National Renewable Energy Laboratory; Own Your Own Power!
• Dept. of Energy; Evaluating Your Site's Solar Resource for Solar Electricity.
• Dept. of Energy; Sizing Your Small Solar Electric System
• Dept. of Energy; Estimating Appliance and Home Electronic Energy Use

Resources

• Database of State Incentives For Renewables and Efficency; Financial Incentives
• Sun City Solar: How to Choose an Electrical Solar Panel System Wizard