Understand your electric bill and usage. Plan for outages, too.

Before buying solar panels or batteries, see what your appliances use and understand your electricity bill. Adiós Factura provides a free solar calculator for exploring options without a credit card or sales pressure.

It simulates production, usage and storage hour by hour so you can estimate how long a battery might last during a power outage. Results depend on the information you enter, and do not guarantee savings or uninterrupted service.

What this solar calculator works out

It is a solar simulator and a panel and battery calculator at once: instead of a yearly estimate, it runs the twenty-four hours of the day against your real consumption and tells you whether the system makes it to the next morning.

• Your town’s sun, not an average: all 78 municipalities of Puerto Rico with their real peak sun hours, or your own irradiance anywhere else. Between Adjuntas and Santa Isabel there is a 16 % spread with the same gear.
• Your appliances, one by one. Every A/C with its own schedule and thermostat, the freezer, the water heater, the pool pump, the dryer.
• Cloudy days back to back. How many the battery holds without starting the generator — the question that matters after a hurricane.
• What nobody subtracts. Heat on the panel, dust in the air, shade, the wire, and the inverter eating more than 1 kWh a day just from being on.
• MPPT layout with the code open. Cold voltage per NEC 690.7, design current per 690.8, and a warning when a string goes past the channel’s short-circuit rating.
• Weight and area on the roof, battery-to-inverter compatibility, and net metering with the grid.

Filing with the grid

In Puerto Rico the simulator tells you which path yours takes from the inverter output in kW AC: up to 25 kW it is the Expedited Registration under Act 17-2019, and above that the process changes. That comes free, with the rest of the calculation. The whole route with LUMA — the seven steps of the Expedited Registration, the attachments, the 30 days and what to do when they do not answer — is in the guide to filing with LUMA. It comes with the Professional plan. Elsewhere, interconnection is up to your utility; the system calculation is the same.

The answers, worked out

Six pages where the number is not written down: it is run through the same engine as the simulator.

• How much does it cut your bill? The bill before and after, with net metering (in Puerto Rico, Act 114-2007) — and why it never reaches zero.
• How many days does it last with no grid? Three real households, by battery and panels, day by day on overcast weather with no generator.
• How many panels do I need? To cover a typical day and to cover an overcast one — two very different answers.
• How much does an A/C use a day? By size, schedule and thermostat — from 4 to 17.7 kWh for the same 12,000 BTU unit.
• Do I need a generator? The hours the generator would run on the first day with no grid and on the third — which do not say the same thing.
• How much does each appliance use? The whole house: fridge, freezer, water heater, dryer, pumps and the stove.

Price

Calculating is free: the whole system hour by hour, how many days it lasts, and sharing by link. The Professional plan is $20 a month or $200 a year, and there is a one-month pass for $30 with no subscription. It includes the MPPT split, roof weight and area, battery compatibility, the filing guide (Puerto Rico), your own prices and the PDF with your logo for the engineer.

For installers, licensed electrical engineers and homeowners who want the numbers before they spend.

This is for comparing scenarios. It does not replace the design of a licensed electrical engineer.

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