Evaluating solar options? The Model T days are over; four key considerations.

You've decided it's time to (re)-investigate installing solar. Your hesitancy may be logical: You do not need to go solar, and you’re unsure how to assess and assemble the pieces, let alone compare offerings. It can be puzzling. Your caution (and even procrastination) actually positions you well. The solar industry has improved dramatically from the Model T days.

Early car buyers had similar concerns: Do I buy internal combustion engine, electric, or steam? What starter makes sense? What about the brakes, or the dashboard, or the tire lifetime? Do I need a car? If so, who can I trust and will it work/be dependable?

Homeowners who went solar in the early days had to consider panel composition, wiring, inverter design, roof attachments, warranties, and even potential fire hazards. Fortunately, solar equipment is now similar to automotive offers from the early ‘80s. We no longer need to ask about where the engine was made, the engine compression, the electrical system, etc. For cars, we now shop for benefits and outcomes, and we have specific metrics to help gauge alternatives: fuel efficiency, acceleration (zero-to-60), safety test results, stopping distance plus all the new features and benefits available.

For solar, here's what matters most on the equipment front (i.e., questions you should engage and pose to your solar provider):

  1. What is the likelihood the system will generate the annual energy forecasted? Thereby, can the solar company point to a significant group of local, monitored homes and compare forecast to actual generation? A simple metric to calculate system productivity: total annual electricity (kWh)/system size (kW-DC). For south-facing systems with no shade, this number should be about 1,500 kWh/kW. East- and west-facing systems produce ~8% less. (The likelihood of actually generating the energy promised falls dramatically as the actual productivity value increases above this threshold.) And, don’t get confused by panel efficiency: It simply reduces the area required for a system, and has a modest impact on the system’s production.
  2. Does the equipment come from Tier-1, investment-grade suppliers? For solar panels: Canadian Solar, SunPower, LG and a handful of others qualify. For inverters: SMA, SolarEdge, and ABB.
  3. What is the likelihood my product warranties will be valid? Amplifying the above point, the current and future financial stability of the manufacturer is imperative. A 25-year warranty is only as good as the company behind it; do your homework (or, better yet, press your solar provider to evidence the manufacturers’ solvency).
  4. How do I know I’m getting a fair price? One way to standardize pricing for an apples-to-apples assessment: Divide system cost by the the system size (watts), so you have the cost per watt. The gross investment (pre-tax credit) for most home systems today should be $3.50 per watt or less for a Tier-1 system installed by a first-rate contractor.

Solar is transitioning from an art form to science. In so doing, your task is simplified as you endeavor to generate your own power. (And, solar, in our opinion, is the only investment in your home that generates a reliable return.)