Solar Panel Installation and Roofing Installation in Westfield, NJ | 32 Panels on a Northwest Roof

Westfield, NJ · Client since October 2019

Brian Lu has been a Green Sun Energy Services client since October of 2019, when the roof and the solar array were bought on the same day. The roof was finished on 22 December 2019 and the array eight days later.

Two layers off, 2,700 square feet on

This roof had been covered over once already, so two layers of old shingle came off rather than one: twice the tear-off, twice the disposal, and the only way anybody sees the deck a solar array is about to be fastened to. GAF deck protection went over the exposed sheathing with ice shield up from the gutter edges, then a GAF Timberline HDZ system with a 50-year warranty, aluminum drip edge along 205 feet of rakes and eaves, and a ridge vent along the peak.

32 panels on a roof facing northwest

Thirty-two LG 350 watt panels came to 11.2 kW on Ecolibrium Solar mounting, finished on 30 December 2019, in a single group on the back of the house at a 23-degree pitch. That face points northwest, at an azimuth of 307 degrees, and the design models it at about 69 percent of what the same array would make on a due-south roof at an ideal pitch. A SolarEdge SE10000H runs it with an optimizer on every panel. PSE&G is the utility and the first year was designed for about 9,817 kWh.

Why a northwest roof was still worth doing

Nobody would choose this orientation, and it is the orientation this house has. The choice in front of the household was never between a northwest roof and a south one; it was between using the roof they own and not having an array at all. Sixty-nine percent of ideal, spread across 11.2 kW, still comes to roughly 9,817 kWh in the first year. It is also why the array is large: where the orientation cannot be improved, the area can, and thirty-two panels is what the back of this house holds.

Why the roof went first

Eight days separated the two jobs and the sequence was deliberate. An array is bolted down for twenty-five years and more, so a worn roof underneath one becomes a second job later — panels off, roof on, panels back. Doing the tear-off first also meant the deck was seen and covered properly before a single mount was fastened to it, which on a roof that had already been shingled over twice is not a detail worth skipping.