Millennium 3 Energy, Contractors  Solar Energy, Hagerstown, MD     
301-745-4180
phil.kelly@m3-energy.com
Hagerstown, MD
MHIC# 131841

About Panels and Systems

  • A typical residential solar panel has 60 solar cells and is approximately 40" wide and 66" tall. It weighs 40-45 pounds. The solar cells are those squares that are about 5" to a side and arranged 6 across and 10 down on a typical panel.

  • For larger commercial systems a good choice is often larger panels... 40" wide by 79" tall. These are 72 cell panels... 6 across by 12 down.

  • The most common panels are silicon based, and are either mono-Silicon (using thin wafers of silicon cut from a silicon crystal), or poly-Silicon (crushed crystallized silicon that is reshaped into rectangles for use in a solar panel). In most climates which of these is used doesn’t much matter. Mono-Silicon panels generally have slightly higher power output.

  • Panels come from all over the world, but 6 of 10 of the largest solar panel companies manufacture in China, and most panels in use throughout the world were Chinese made. Other solar panel manufacturing is located in Japan, S. Korea, Germany, the U.S., and various other countries.

  • One way solar panels are rated is by how much power they produce. Power ratings improve bit by bit all the time. In 2009 when we did our first project the power rating on a typical panel was maybe 225 Watts or 235 Watts. In 2016 we can procure panels of the same size that are rated at 300 Watts.  This means more energy (kilowatt hour) output from the same amount of space.

  • Probably the best way to be sure you get “good quality” panels is to ask about how your installer procures. Millennium 3 Energy only purchases from large reputable distributors. Lately, we have mostly used SolarWorld panels (Made in USA).

  • Photovoltaic systems are entirely scalable… That is, you could have a 1-panel array or a 1 million panel array.

  • A solar system typically comprises solar panels, a racking system for attaching the panels, an inverter or inverters that convert the power from DC to AC, and the electrical conduit, wiring, boxes, etc. that it takes to connect the solar system to your home or facility electrical system.


Mono Silicon panels have the little diamond shapes among the cells. That’s because of the shape of a Silicon crystal.
Poly Silicon panels have the all-rectangle look, and generally more bluish in color.