How solar works on a project

Solar is often the first trade a client asks about, and it is the trade that depends most on everything else on the job. The array is sized against a building load that the other trades set.

How it works

Sunlight lands on the roof. The angle of the roof, shading from trees or chimneys and local weather decide how much energy reaches the panels. Panels turn that light into direct current. An inverter changes the direct current into the alternating current a building and the grid use. A meter records what the building consumes and what flows to or from the grid.

The array is sized against the building load, not against the roof alone. A house that cuts its load with envelope work and a heat pump needs a smaller array for the same result. In an Evoa Systems project that change moves through the design on its own.

Key terms

• Kilowatt is the size of the array at one moment.
• Kilowatt hour is the energy it produces over time.
• Offset is the share of the building load the array covers.
• Inverter is the equipment that converts direct current into alternating current.

Where it fits in a project

Solar usually comes after the envelope and the heating and cooling equipment are chosen, because those two decide the load. Storage is often sized with the array, since a battery changes when the solar energy gets used. Cost, incentives and payback all land in the same proposal as the rest of the trades.