Batería doméstica Payback Period Calculator

The basic formula

"Is a batería doméstica worth it?" It is the question we hear most often. The honest answer: that depends on your situation. But with the right calculation, you can predict it fairly accurately. In this article, we show you how to calculate the payback period, with concrete scenarios and current 2026 prices.

Sounds simple, but the annual savings consist of several components:

• Avoided feed-in — electricity you store instead of inyección a la red at a low rate
• Tarifa dinámica advantage — charge cheaply, discharge at a high rate
• Avoided costes de inyección — some suppliers charge fees for inyección a la red to the grid
• devolución del IVA — one-off 21% of the purchase price

Scenario 1: Average hogar with paneles solares

Assumptions: 12 paneles solares, 4,200 kWh generation por año. 3,800 kWh annual consumption. 60% of generation is currently inyectado (2,520 kWh). Energy purchase price: €0.28 per kWh. Feed-in tariff after 2027: €0.07 per kWh. Batería doméstica: 10 kWh, purchase price €4,500.

Savings calculation por año

Período de amortización calculation

With an expected vida útil of 15-20 years, you continue to earn €463+ por año for 7-12 years after the payback period. That is a total return of €3,200-5,500 over the vida útil. Período de amortización: 7.7 years.

Scenario 2: Small hogar, plug & play battery

Assumptions: 8 paneles solares, 2,800 kWh generation por año. 2,500 kWh annual consumption. Batería doméstica: 5 kWh plug & play, purchase price €1,800.

Cálculo

Plug & play batteries often have a shorter payback period due to the lower purchase price and the absence of costes de instalación.

Scenario 3: Large hogar with bomba de calor

Assumptions: 20 paneles solares, 7,000 kWh generation por año. 8,000 kWh annual consumption (including bomba de calor). Batería doméstica: 15 kWh instalación fija, purchase price €7,000 + €500 installation.

Cálculo

With a large system, the absolute savings are higher, but the payback period is slightly longer due to the larger investment. However, the total return over the vida útil is considerably greater.

Factors that shorten the payback period

1. Dynamic contrato de energía

With a contrato dinámico, you can actively trade on precio de la electricidads. Charge at €0.05/kWh, discharge when the price is €0.35/kWh. This can yield €100-400 extra por año, depending on your capacidad de la batería and how actively you trade.

2. Rising precio de la energías

The calculations above are based on current prices. If precio de la energías rise by 3% por año, your savings increase each year and the payback period shortens by 1-2 years.

3. Costes de inyección

An increasing number of proveedor de energías charge costes de inyección. This makes a batería doméstica extra profitable because you avoid those costs.

4. devolución del IVA

The one-off 21% devolución del IVA reduces your net investment directly. This is a significant advantage — on a battery of €5,000, that saves €1,050.

5. Subsidies

In some municipalities and provinces, subvenciones are available for baterías domésticas. Always check the current schemes with your municipality and on the RVO website.

Factors that lengthen the payback period

• Low autoconsumo — If you use little electricity, you won't fill the battery daily
• Few paneles solares — Less surplus means less to store
• Fixed contrato de energía — No advantage from tarifas dinámicas
• Expensive system with high costes de instalación — The investment is larger
• North-facing roof — Less generación solar

Comparison: payback period by battery type

The sweet spot for most hogares: a 10 kWh system with a payback period of 6-8 years.

Preguntas frecuentes

Is a batería doméstica profitable in 2026?

Yes, for most hogares with paneles solares, a batería doméstica is profitable with a payback period of 6-10 years. Especially after the compensación neta scheme ends in 2027, the financial advantage grows. Assume a net return of 8-12% por año on your investment.

How do I calculate my own payback period?

Take your annual excedente solar (kWh that you inyectar), multiply this by the difference between your precio de la energía and the tarifa de inyección, add any tarifa dinámica advantage, and divide the net purchase price (after devolución del IVA) by this annual savings.

What is the payback period without paneles solares?

Without paneles solares, the payback period is longer: 10-15 years. You only earn on the difference between cheap and expensive hours with a contrato de energía dinámico. This yields €150-350 por año, depending on your strategy and capacidad de la batería.

Does the increase in my valor de la propiedad count?

A batería doméstica can increase the value of your property, similar to paneles solares. However, this is not included in the standard payback period calculation. It is an additional benefit.

What about degradación de la batería?

Baterías domésticas gradually lose capacity, similar to a phone battery but much more slowly. After 10 years, a good LFP battery still has 80-90% of its original capacity. This effect is small and already accounted for in the manufacturer's garantía terms.