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See how this system cost would grow if invested instead with the Compound Interest Calculator, for a rough opportunity-cost comparison.
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Good to Know
This projection assumes constant electricity usage and a steady rate of electricity price inflation — actual utility rates, your household's usage, and panel performance over time all vary. This calculator doesn't assume a federal tax credit, since the federal residential solar credit ended for homeowner-purchased systems installed in 2026 or later.
Disclaimer
This calculator provides estimates for informational purposes only and does not constitute financial, medical, legal, or tax advice. Always consult a qualified professional about your specific situation.
How This Calculator Works
Solar payback period is the number of years it takes for a system’s electricity savings to cover
its net upfront cost, found by projecting those savings year by year against rising electricity
prices. Enter your solar system’s cost, any state or local incentive, your current monthly
electric bill, how much of that bill the system is expected to offset, and an assumed rate of
electricity price inflation, and this calculator projects that payback period along with your
total savings over the system’s expected lifespan.
A note on federal tax credits: this calculator does not assume a federal tax credit by
default. The federal residential solar tax credit (the Residential Clean Energy Credit) was ended
by the One Big Beautiful Bill Act, signed July 4, 2025, for any homeowner-purchased system
installed January 1, 2026 or later. If you’re evaluating a solar lease or power purchase agreement
instead of buying the system outright, a separate business-side credit remains available to those
providers through 2027 — check with your installer about whether that’s reflected in their
pricing.
The Formula
Unlike a simple “cost ÷ monthly savings” estimate, this calculator projects savings year by
year, since electricity rates — and therefore your savings — tend to rise over time:
Year N Savings=(Monthly Bill×Offset%)×12×(1+Inflation Rate)N−1
The payback period is the point where cumulative savings across all years first equals or exceeds
the system’s net cost (after any incentive).
Worked Example
A $20,000 system with no incentive, a $150/month electric bill, a 90% offset, 3%
annual electricity rate inflation, over a 25-year system lifespan:
Year one savings: $150 × 90% × 12 = $1,620.
Cumulative savings grow each year as electricity rates rise 3% annually.
Payback period: about 10.7 years — the point cumulative savings reach the $20,000 system
cost.
Total savings over 25 years: about $59,064, for a lifetime net savings of about
$39,064 after subtracting the system’s cost.
Cómo funciona esta calculadora
El período de recuperación solar es la cantidad de años que tarda el ahorro en electricidad de
un sistema en cubrir su costo neto inicial, calculado proyectando esos ahorros año por año frente
al aumento de los precios de la electricidad. Ingresa el costo de tu sistema solar, cualquier
incentivo estatal o local, tu factura eléctrica mensual actual, qué parte de esa factura se espera
que el sistema compense, y una tasa asumida de inflación del precio de la electricidad, y esta
calculadora proyecta ese período de recuperación junto con tu ahorro total durante la vida útil
esperada del sistema.
Una nota sobre los créditos fiscales federales: esta calculadora no asume un crédito fiscal
federal de forma predeterminada. El crédito fiscal federal para energía solar residencial (el
Crédito Federal por Energía Limpia Residencial, o Residential Clean Energy Credit) fue eliminado
por la One Big Beautiful Bill Act, firmada el 4 de julio de 2025, para cualquier sistema comprado
por el propietario e instalado a partir del 1 de enero de 2026. Si estás evaluando un arrendamiento
solar o un acuerdo de compra de energía en lugar de comprar el sistema directamente, un crédito
separado para el lado empresarial sigue disponible para esos proveedores hasta 2027 — consulta con
tu instalador si esto se refleja en su precio.
La fórmula
A diferencia de una simple estimación de “costo ÷ ahorro mensual”, esta calculadora proyecta el
ahorro año por año, ya que las tarifas eléctricas — y por lo tanto tu ahorro — tienden a subir
con el tiempo:
An˜o N de ahorro=(Factura mensual×Compensacioˊn%)×12×(1+Tasa de inflacioˊn)N−1
El período de recuperación es el punto en que el ahorro acumulado de todos los años iguala o
supera por primera vez el costo neto del sistema (después de cualquier incentivo).
Ejemplo resuelto
Un sistema de $20,000 sin incentivo, una factura eléctrica de $150/mes, una compensación
del 90%, una inflación anual de la tarifa eléctrica del 3%, durante una vida útil del
sistema de 25 años:
Ahorro del primer año: $150 × 90% × 12 = $1,620.
El ahorro acumulado crece cada año a medida que las tarifas eléctricas suben un 3% anual.
Período de recuperación: aproximadamente 10.7 años — el punto en que el ahorro acumulado
alcanza el costo del sistema de $20,000.
Ahorro total durante 25 años: aproximadamente $59,064, para un ahorro neto de por vida de
aproximadamente $39,064 después de restar el costo del sistema.
Is there still a federal tax credit for solar panels?
Not for a homeowner-purchased system installed in 2026 or later — the federal Residential Clean Energy Credit was ended by the One Big Beautiful Bill Act, signed July 4, 2025. A separate credit remains available through 2027 to businesses providing solar leases or power purchase agreements, which may be reflected in that pricing instead.
Why do savings grow every year instead of staying flat?
Electricity rates have historically risen over time, so the same offset percentage of your bill is worth more in later years. This calculator projects savings year by year using your assumed inflation rate, rather than a flat monthly-savings estimate that would understate long-term savings.
What if my state or local area has an incentive program?
Enter it as a percentage in the incentive field — it reduces the net cost the payback period is calculated against. Incentive programs vary widely by location, so check with your local utility or state energy office for what applies to you.
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