Net Metering

Net metering is a billing mechanism that allows owners of solar panels (or other on-site renewable generation) to receive credit for excess electricity they feed back into the utility grid. Instead of needing a battery to store every excess kilowatt-hour for later use, the homeowner effectively "banks" surplus generation with the utility as a credit, then draws on that credit — typically at the same retail rate — when their system isn't generating enough, such as at night.

This arrangement is what makes grid-tied solar financially attractive without requiring expensive battery storage for most households. A solar system's economics, including how quickly it pays for itself, depend heavily on the local net metering policy, since export credit rates range from full retail value to significantly discounted wholesale rates depending on the jurisdiction and utility. The Solar Panel Calculator and Solar Panel Wattage Calculator both incorporate net metering assumptions when estimating bill savings and appropriate system sizing.

Net metering is also relevant to highly efficient buildings such as those meeting the Passive House standard, since a building with very low energy demand needs a much smaller solar array to offset its remaining consumption fully, making net-zero energy status achievable with a modest, well-sized system.

• Export credit rate varies widely by policy: Some utilities credit exported solar at the full retail electricity rate, others at a lower wholesale or "avoided cost" rate under a separate framework sometimes called net billing, and this single variable is one of the biggest factors affecting solar payback time.
• Annual true-up periods determine what happens to leftover credits: Most net metering programs reset or cash out accumulated credits on an annual cycle, often at a reduced rate, so oversizing a solar system well beyond typical usage yields diminishing financial benefit once annual credits exceed the true-up compensation.
• Correct system sizing matters more under net metering: Because unused excess credits are often only partially compensated, using the Solar Panel Wattage Calculator to size a system closer to actual annual consumption typically produces better financial outcomes than maximizing panel count.
• Highly efficient buildings need smaller solar systems: A building built to the Passive House standard, or otherwise retrofitted for low energy use, requires proportionally less solar capacity to reach net-zero status under net metering, since there is simply less annual consumption to offset.
• Policy can change over time: Several jurisdictions have transitioned from full retail-rate net metering to reduced-rate net billing structures in recent years, so homeowners evaluating solar economics should check current local rules rather than relying on historical policy assumptions.