So, the Sun shines on Earth and in that sunshine there is energy. Plants convert that energy into mass because energy is mass. E = mc2. Energy equals Mass times a constant (which is not important here). We eat the plants for energy, or we eat animals that eat the plants. That’s how we survive.
Well, solar panels are humans’ attempt at making “plants” that convert the Sun’s energy into energy we use – to heat, chill, or light our homes, to power our TV’s, fridges, computers, etc. Well, it’s not easy converting that sunshine into energy we can use. And as it turns out, most solar panels convert 12-15% of the Sun’s energy that falls on the panel. The Sun dumps ~1,000 W/m2 at sea level on a clear day (source: wikipedia).
Stop searching for the ‘best’ or ‘most efficient’ solar panels. Stop trying to compare brands. The solar panels don’t matter. Obviously they matter in terms of the solar pv system as a whole, but which panels you use, isn’t important. Let me explain.
1. All solar panels are warrantied for 20-25 years, which means the manufacturer guarantees the panels will still be producing at least 80% output 25 years from now. It’s the same for all brands. Don’t believe me? Ask the guy selling them.
Should I use Sanyo 200’s or Suntech 270’s? SunPower 210’s or Canadian Solar 240’s? Which size solar panel you use depends mainly on how much roof space you have available and how much electricity you plan to use (with solar power). Below are 6 steps to calculate which size solar panels you need for your building.
Step 1: Know Your Electricity Usage
Gather your old electricity bills for the past 12 months. Contact your utility company if you don’t have them and your electricity provider should gladly send you a printout with your past electricity usage. You’re looking for 2 things: (1) your monthly kW/h usage, and (2) your monthly cost.
Step 2: Know your Roof Direction
Grab a compass (maybe your car navigation, or check Google Maps) and figure out which way is South. Go outside, look at your roof and see how much roof space is facing South, Southwest, East and West. The more South the better, but West is actually okay.