Solar Glossary
Solar Glossary: Key Terms for Homeowners
Understanding Solar Terms for a Smarter Investment
Understanding solar energy can feel complex, but having the right information makes all the difference. That’s why Get Smarter Solar with Axia has created this comprehensive glossary to help Los Angeles County homeowners learn the key terms in solar technology. Whether you're considering rooftop solar or exploring ground mount options, understanding components like photovoltaic (PV) solar cells, integrated micro-inverters, and stand-alone inverters will help you make the best energy choices. We also cover important electrical concepts, including the main service panel (MSP), overfed panels, and underfed panels, so you can better understand how solar connects to your home’s power system. Browse our list of solar terms below and take the first step toward a smarter, more sustainable future in LA!
- Photovoltaic – Photovoltaic (PV) solar converts sunlight directly into electricity. There are other types of solar that harvest sunlight for generating heat.
- PV Solar cell – A solar component made of silica (most commonly) and electrical wires, usually covered in protective glass.
- Solar Module – Known more commonly as a “solar panel”, a solar module is comprised of many solar cells mounted within a metal frame and wired to operate as a single solar unit.
- DC to AC – Direct electrical Current (DC) to Alternating Current (AC).
- Inverter – An electrical device that converts DC to AC.
- Stand-alone Inverter – An inverter mounted on a wall that converts the DC current of several solar modules, which have been strung together to the stand-alone inverter, into AC current.
- Integrated Micro-Inverter – A small inverter integrated into a solar module to convert the DC of the solar cells into AC.
- AC Module – A solar module with an integrated micro-inverter that outputs AC current.
- Array – A set of solar modules arranged together on a roof face, facing the same direction. If stand-alone inverters are used, the modules in an array would be strung together to an inverter.
- Azimuth – The position of the sun in degrees up to 360° relative to the cardinal directions, North, South, East and West. 0° is due North, 90° is due East, 180° is due South, and 270 ° is due West. 180° is the most optimal for solar in the Northern Hemisphere.
- Solar access – The percentage of access that an array has to the sun during sunlight hours. A roof with 100% solar access has no shade at any time of any day during the year. Any obstruction causing shade will reduce solar access.
- Irradiance – The amount of electromagnetic radiation that hits a surface per unit of time and area. A roof plane with both a good azimuth and a high percentage of solar access will have high irradiance, which is good for it to be potentially used in generating PV solar power.
- AHJ/Authority having Jurisdiction – Any City, State and/or Utility that controls requirements for installing solar.
- Fire Setback – A section of open space required by the fire department around PV solar arrays, to allow for the safe maneuvering of the fire department in the event that they must access the roof during a fire incident. Different state and city AHJ’s may have different setback requirements for solar.
- Flat roof – A roof is considered to be “flat” if it is less than 10 degrees, or 2:12 pitch. Different setback measures and installation requirements may apply.
- Electric Grid – The network of power plants, transmission lines, and distribution centers that delivers electricity, and that also receives electricity from residential and commercial solar.
- Backfeed – Electricity originating from a non-utility power source, including solar electricity, that passes through an MSP and onto the electric grid.
- Grid Tied Solar – Solar that requires interconnection with the Electric Grid, as opposed to Off Grid Solar that is designed to be independent of the electric grid.
- Main Service Panel (MSP) – The main electrical panel of a home/property that connects to the Electric Grid. This panel will have a main breaker switch that can shut off power to the entire home if tripped and will also be connected to the utility meter.
- Conduit – Metal piping for hosting electrical wires.
- Overfed Panel – An MSP with wiring going upward to a riser on the roof to connect to overhanging electrical wires.
- Underfed Panel – An MSP with wiring leading downward to underground conduit leading to the electrical grid.
- Ground Mount – A solar system installed on the ground vs on a roof top. Ground Mounts are expensive and are very rarely installed due to several elements that must be aligned for them to make sense, including that the property is landscape qualified with large, unshaded, non-recreational space to host a ground mount.
