ENERA - solar systems

We keep hearing the same line: my roof doesn't face south, so solar just won't work for me.

Truth is, a house perfectly oriented to the south is the exception, not the rule. Roofs come multi-sloped, with panels scattered across two or three sides. Some are flat. Some have an angle no engineer would ever pick on purpose. And almost every time, there's one simple fix, add a few more panels.

Here's a typical case. Flat roof, the client doesn't want tilted mounts sticking up because it looks off, or sometimes the community board just won't allow anything rising above the roofline. We're working with a 5 kW inverter, and the standard setup would be 10 panels at 500 watts, one to one. In this case we install 12, sometimes 14. The panels sit almost flat and spend half the day in less than ideal light, so the extra panels make up for the loss and the system still hits its rated 5 kW, not 3 or 4.

Different case now. Roof with a great angle, facing straight south. 6 kW inverter, and instead of the standard 12 panels, we put in 16. The point isn't to squeeze out more peak power, the inverter will never put out more than its 6 kW no matter what. The point is to keep it producing that 6 kW for most of the day, not just an hour around noon.

People usually ask, why not just install an 8 kW inverter then. Two reasons. Most homes run on a single phase, and single phase connections are typically capped around 6 kilowatts anyway. Second, that inverter costs noticeably more, and it'll only actually hit its rated 8 kW under perfect conditions, summer, around noon, at exactly the right angle we just talked about.

So if someone told you your roof isn't good enough for solar, chances are they just forgot to add a couple of panels.

How's your roof looking, facing south, or does it have its own personality too?