Seven to ten years without a battery, approximately nine to twelve years with a storage system. These are, in 2026, the most realistic payback times for a well-sized domestic photovoltaic system, installed on the main residence and eligible for the 50% tax deduction. Without benefits, however, the picture changes: it can take ten to eighteen years without storage and fourteen to over twenty years with a battery to recover the expense.
In fact, the answer to the question “how much is photovoltaic worth” therefore depends less on the number of panels and much more on four factors: the cost of the estimate, the geographical position, the amount of self-consumed energy and the possibility of recovering the Irpef deduction.
How much does a rooftop system cost today
The prices of a photovoltaic system observable on the market are highly variable: for a residential system of around 4-5 kW – sufficient in many cases for a family that consumes between 3,000 and 4,000 kWh per year – a turnkey cost of between 7,000 and 10,000 euros can be estimated. By adding a battery of around 7-10 kWh, the overall cost can rise approximately between 14,000 and 19,000 euros. Higher quotes may exceed this threshold if there are difficult roofs, scaffolding, electrical upgrades, backup systems or premium components.
In 2026 the renovation bonus allows you to deduct 50 percent of the expense when the intervention concerns the main residence. For other properties the ordinary percentage is 36 percent. However, the benefit is not an immediate discount: it is recovered in ten annual installments and requires a sufficient income tax from which to subtract the deduction. The storage system can also be included in the relief when it is connected to the photovoltaic system.
How much does a 4.5 kW system produce
Production changes significantly along the peninsula. With well exposed panels, oriented towards the South, without significant shadows and with normal overall losses, a 4.5 kW system can produce approximately:
| Area | Estimated annual production |
| Northern Italy | 4,800-5,100 kWh |
| Central Italy | 5,500-6,000 kWh |
| South and islands | 6,300-6,800 kWh |
They are average values. A roof facing east or west may produce less energy throughout the year, but distribute production better between morning and afternoon. Shading, unfavorable inclination and high temperatures can however reduce the result. The typical drop for modern silicon panels is approximately between 0.26 and 0.40 percent for each degree increase: with external temperatures of 35 °C, a poorly ventilated panel on the roof can reach around 55 to 65 °C and produce 9 to 14 percent less power than it would have, with the same light, at 25 °C.
How much is the energy produced really worth?
It is also good to consider that not all kilowatt hours produced have the same value. The energy produced by the panels and consumed immediately at home is the one that generates the greatest savings, because it avoids drawing the same quantity of electricity from the grid. Its economic value can be estimated at approximately 23-27 cents per kWh, depending on the tariff applied by your supplier. However, it does not coincide with the overall average cost of the bill: some items, such as the fixed quotas for marketing, transport and management of the meter, continue to be paid even after the installation of the photovoltaic system.
Excess energy fed into the grid is worth much less. For photovoltaic, the minimum guaranteed price is 47.5 euros per MWh, i.e. 4.75 cents per kWh. The difference is therefore notable: a self-consumed kWh can be worth five times a kWh sold to the grid. For this reason, an oversized system, which produces much more than the family can use, can be less convenient than a smaller but better calibrated system.
How many years will it take to pay off?
To estimate the return we can consider an average family that consumes around 3,500 kWh per year, a 4.5 kW system. Without the battery, a self-consumption share of close to a third of production has been hypothesized. With accumulation the share can rise towards 65-75%, but it cannot however exceed the actual consumption of the house.
The indicative result is this:
| Area | Without battery, 50% deduction | With battery, 50% deduction | Without battery, no bonus | With battery, no bonus |
| North | 8-10 years | 9-12 years | 13-18 years | 16-22 years |
| Center | 7-9 years | 9-11 years | 11-16 years | 15-20 years |
| South and islands | 6-8 years | 8-11 years | 9-14 years | 14-19 years |
For a second home, with a 36% deduction, the recovery tends to be extended by about one or two years compared to the scenario with a 50% bonus. The accounts do not include interest on any financing, insurance, extraordinary roof repairs or future replacement of the inverter.
Because the battery doesn’t always save more
The battery increases independence from the grid, but not necessarily the profitability of the investment. Without storage, the energy produced during the day and not used is sold for a few cents. The battery allows you to store it and use it in the evening, transforming a kWh that would have been sold for around 5 cents into a kWh that avoids a purchase costing around 25 cents.
The additional benefit is therefore around 20 cents for each kWh actually moved from the day to the evening. If the battery can transfer between 1,500 and 2,000 kWh per year, the additional economic benefit can be in the order of 300-400 euros.
Faced with an additional cost of 7,000-10,000 euros, the battery alone can take more than fifteen or twenty years to pay for itself without deductions. With the 50% tax recovery the result improves significantly, but it depends on the price of the accumulation and how much is actually used. A very large battery combined with low domestic consumption risks not discharging completely and thus paying for a capacity that does not produce corresponding savings.
It should also be considered that commercial guarantees for domestic batteries are generally between ten and fifteen years, often with limits on the number of cycles or residual capacity. If the estimated payback time exceeds the duration of the guarantee, the investment becomes more uncertain.
How to reduce return times
This does not mean that photovoltaics are no longer convenient, but that today it is above all convenient to use energy when it is produced. The most effective way to quickly recover your investment is not necessarily to buy more panels or a bigger battery. It means increasing self-consumption in the central hours of the day by programming the washing machine, dishwasher, dryer and electric boiler. Or choose a heat pump, an induction hob or an electric car that increase electricity needs and can make a larger system convenient.
On the contrary, a family that consumes little and concentrates almost all of its needs in the evening hours should carefully evaluate both the size of the panels and that of the battery. Before signing the contract it is advisable to ask for at least three simulations: production expected by the system, monthly and hourly consumption profile, estimated percentage of self-consumption with and without storage. The estimate should also separately indicate the cost of the panels, battery, inverter, paperwork and ancillary works.
When photovoltaics really pays off
So, to sum it up, a battery-free system generally remains the simplest investment and with the most favorable ratio between cost and savings: with the 50% deduction, a well-sized system can pay for itself in around seven to nine years in most of the country. But be careful to correctly size the system with respect to self-consumption. The battery can be useful for those who consume a lot in the evening, want to increase autonomy or want an emergency system in the event of a blackout. But from an economic point of view alone it is not automatically the best choice.
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