What is the 115% rule?

Why the rule exists

Net metering lets you feed surplus generation to the grid and draw it back later, effectively using the grid as storage. That arrangement makes sense when you are offsetting your own consumption. It stops making sense if a customer installs a system several times larger than their needs and exports the bulk of it on residential terms, so the rule puts a ceiling on the ratio.

How it is applied

Your utility compares the system’s expected annual production against your historical annual consumption. Both halves matter, and the first is a model rather than a measurement — which is why the assumptions behind a production estimate are worth reading rather than accepting.

The three cases where it actually bites

You are about to electrify something

An electric car, a heat pump, or a pool pump changes your consumption sharply upward — but the cap is measured against history, not plans. Raise this explicitly with your installer and your utility, because the sizing conversation is different when the load is arriving next year.

You have just moved in

With no consumption history at the property, there is nothing to measure 115% against. Utilities have processes for this, and they involve estimates rather than your bills.

You have already made the house efficient

A well-insulated home with efficient appliances has low consumption, which means a low cap. Efficiency work done before solar shrinks the system you are permitted to install — not a reason to skip the efficiency work, but a sequencing fact worth knowing.

If your utility is municipal or a cooperative

Florida PSC Rule 25-6.065 governs investor-owned utilities. A municipal utility such as JEA or OUC, or a cooperative such as LCEC, sets its own interconnection terms — which may use a different ratio, a different basis, or a programme capacity cap that closes to new applicants entirely. If you are served by one of those, the 115% figure is a useful reference point and not your rule.