Just a quick entry today, with performance data from the first four weeks of my rooftop solar array. The news is both disappointing and hopeful.

During this time span, we used an average of 12.3 kWh per day, which is more than normal for this household. More on that in a moment. To meet that daily demand, just a tick more than half (6.2 kWh) came from solar power production. 6.1 kWh had to be purchased from the utility.

Over time, I think we’ll see the percentage of my electricity needs offset by solar go way up, from roughly 50% to closer to 100% or more. Here’s what I think happened:

  • Household demand was up due to wrapping up a remodeling project from the summer. Lots of power tools plugged in in the garage, and at one point a high-powered fan blowing 24/7. (Don’t ask…it had to be done.)
  • Solar production was weak for days at a time, as we got soaked with much higher than normal rainfall in October. What I’ve observed so far is that the array is of course highly productive on sunny days, surprisingly productive with the indirect light of partly-cloudy days, but scarcely productive at all on those wall-to-wall rainy days that the Pacific Northwest can sometimes have.

As we head in to the darkest weeks of the year now, it’s possible the array will offset even less of my overall electricity needs. But I knew this going in. Spring and summer of 2015 will be the big test.

In 2012, the State Energy Office of the Department of Commerce compiled a directory of renewable energy, energy efficiency, and sustainable products companies in Washington state. They listed some 50 solar installers, about a dozen of which are right here in the Seattle area. Both counts may indeed be higher now, in 2014.

I’ve met with several of the owners and employees of these small businesses, and have come away mightily impressed with the combination of drive, business savvy, and environmental awareness I see in them. These businesses are growing to meet local demand for solar, and they can get almost overwhelmingly busy during the summer months.

So how do you decide who to work with? Here are some tips:

  • Get free site assessments and bids from at least three companies. There are informative variations in the size, placement, panel manufacturers, and costs of the array options they recommend. If you contact a company and they don’t get back to you within a week, that’s an early indication that they are not prioritizing your business. Move on to the next one.
  • Make sure the consultant who comes out to your house spends plenty of time up on your roof, taking measurements and testing your solar window (shading). This is a crucially informative step in the process, typically taking an hour or more. One consultant I met with eyeballed the situation from the ground, and gave me some quick and incorrect advice. Once it was clear that I expected to get up on the roof with him, he later corrected his mistake.
  • Listen carefully to your consultant, but don’t be cowed by industry jargon. Electrical engineering and solar photovoltaics are technical fields, and it is easy to get lost in the verbal thicket of “loads” and “maximum power-point tracking” and “microinverters.” But if you have a basic understanding of what it is you want (the type of panels, where you want them, how many, and so on), stick to it. Turn on your internal radar to detect when a consultant may have an agenda that he’s pushing you to align with. At the same time, establish a friendly and respectful dialogue with your consultant because he may share with you legitimate, real-time information about the solar industry in your area that you’d have no way of knowing otherwise.
  • Look for neighborhood bulk-buying programs, such as those sponsored by Northwest SEED or Go Solar Washington. These can drive down your costs by 10 percent or more, and can simplify your experience by selecting a reputable installer for you. Installers must submit an application to be part of the campaign (they want to because these campaigns generate hundreds of new potential customers who turn out for solar workshops). If you want to be more involved, you can even ask to be part of the selection committee that chooses the installer for the campaign.

Up next: Data, data, and more data! Results from the first month of my solar installation.