How it works
- Your usage. We take the kWh from your CFE bill (or work them out from what you pay) and get the monthly average.
- Your sun. Each state gets a different amount of sun per day (NASA data). With that we calculate what each panel produces where you live.
- Your savings. We compare what you pay today with what you would pay with panels, using CFE's current rates, and how long the investment takes to pay off.
Not sure which appliance raises your bill? Use the appliance energy calculator.
Reading your CFE bill
This calculator needs two things from your bill, which comes in Spanish: the rate (“Tarifa”: 1, 1A, 1B… up to 1F, depending on how hot your town is) and the usage in kWh (“Consumo”). Most home bills cover two months. If your bill shows the history of previous periods, use it: in summer almost everyone uses more.
Price tiers and the DAC rate
CFE charges homes by tiers: the first kWh of the month (básico) are the cheapest because they are subsidized, the next ones (intermedio) cost more, and the excedente costs more than three times the basic price. That is why panels save the most on the last kWh you use.
If your average usage over the last 12 months goes over your rate's limit, CFE moves you to DAC (Doméstica de Alto Consumo), with no subsidy and a fixed monthly charge. Air conditioning pushes many homes there — and that is exactly where solar pays off fastest. More in our guide to the DAC rate.
All my usage, or only what's above the basic tier?
All my usage sizes a system that covers practically all your energy: the bill drops almost to the minimum. Only what's above the basic tier sizes a smaller system that removes the expensive tiers and leaves the subsidized kWh: it costs less and each panel saves more.
What this calculator doesn't include
Shade from trees or buildings, the tilt and orientation of your roof, the street-lighting fee your municipality charges (DAP), future rate changes and panel wear over the years. An installer should check your roof before quoting.
Frequently asked questions
Where do I find my kWh usage on a CFE bill?
On your CFE bill (recibo de luz) the period usage appears in kWh next to “Consumo”, along with your rate (“Tarifa”). Most bills also show a history of your last periods: if you have it, use the average for a more accurate result.
What is the DAC rate and why does it matter?
DAC stands for Doméstica de Alto Consumo (high-consumption residential). If your average usage over the last 12 months goes over your rate's limit, CFE bills you without the government subsidy, at a much higher price. Solar panels can bring your average back under the limit.
How many solar panels does a house in Mexico need?
It depends on how much electricity you use and how much sun your state gets. The calculator divides your usage by what each panel produces where you live and rounds up. An installer confirms it after checking your roof, shade and orientation.
Is the result exact?
No. It is an estimate so you know whether solar makes sense and roughly what size system you need. The final price and real production depend on the equipment, the roof and the installation. For an exact number you need a quote.
What happens to the energy my panels produce and I don't use?
Most homes connect their panels to the CFE grid with an interconnection contract (net metering): the surplus you send to the grid during the day is credited against what you use at night. The exact terms are in the contract you sign with CFE.
Learn more: How many solar panels do I need? · The CFE DAC rate explained