How much does solar cut your power bill in Puerto Rico?
Run hour by hour, with the net metering rules of Act 114-2007 · 2026-09-11
A house with one A/C at night pays about $89 a month to LUMA. With 14 panels it pays $4 — and that is the fixed service charge, not a saving: you pay it whether you use a single watt or not. The bill does not reach zero. It gets there in a month of clear days and in a month of overcast ones alike, which is what makes the number worth quoting.
Nobody can honestly give you one percentage, and this page will not either: what your bill does depends on the weather of your month. So every cell below is a range between a month of clear days and a month of overcast ones. Where the two ends meet, the system covers the house whatever the sky does.
The bill, by house and by system size
Monthly bill at LUMA's residential average of 0.2367 $/kWh, with the surplus swapped one for one against what you buy back — which is what the law allows.
| The house | No solar | 8 panels | 14 panels | 20 panels |
|---|---|---|---|---|
| The essentials 198 kWh a month |
$51 | $4 | $4 | $4 |
| With one A/C at night 309–360 kWh a month |
$77–$89 | $4–$32 | $4 | $4 |
| How people actually live 759–984 kWh a month |
$184–$237 | $84–$136 | $4–$102 | $4–$68 |
Why the bill does not go to zero
Two reasons, and both are arithmetic, not fine print.
The fixed charge. $4 a month for being connected. Even the largest system on this table leaves a bill of $4, and every cent of that is the meter itself.
The night. Panels produce during the day and the house spends at night. Under net metering the surplus you send in the afternoon is credited against what you draw after dark, one kWh for one kWh — but only up to what you buy back. Beyond that it becomes carried credit, and carried credit is not money.
What happens to the surplus
It carries month to month until the June closing. What is left then is paid at ten cents per kWh, or the rate minus the fuel (FCA) and purchased-power (PPCA) adjustments — whichever is greater — and 25 % of it goes to the public schools, which is in the law and worth knowing before you oversize on purpose.
Which is the honest argument against building a system far bigger than the house: past the point where the surplus stops being swapped, every extra panel is paid at a fraction of the rate.
Work out your own bill, hour by hour →
Free, no card and no sign-up. Your appliances one by one, your town's sun, and what is left to pay.
Rate: 0.2367 $/kWh, LUMA's residential average for 2024 (EIA). Fixed charge $4 a month. Net metering under Act 114-2007, art. 5(e), with the June closing — protected until at least 2030 by Act 10-2024. Consumption and production come from running the same hour-by-hour engine as the simulator, in the central valley, on a 17° roof facing south. Your bill will differ with your rate bracket, your roof and what you actually leave running.