Are Solar Panels Worth It for Your Home? Costs, Savings and Payback

Solar panels can pay for themselves in many homes, but not in all of them, and the answer depends on far more than how sunny it is. The installation price, how much electricity you use and when, what you pay for power from the grid, how any surplus is valued, the state of your roof and how many more years you will live there all matter. This guide explains how to work it out, shows three worked examples with every assumption visible and covers the cases where the investment does not pay off. It uses Spain as a clearly labelled regulatory example; if you live elsewhere, the rules on exported electricity, incentives and permits will differ.

How solar panels for self-consumption work

A self-consumption photovoltaic (PV) system turns sunlight into electricity at your own home. In most cases it stays connected to the grid: while the panels are producing, the home uses that electricity first; when they do not produce enough (at night, under cloud or with heavy use), the rest comes from the grid as usual, as the Spanish energy agency IDAE explains.

• Solar panels or PV modules: generate direct-current electricity when exposed to light.
• Inverter: converts that direct current into the alternating current used by the home's sockets and appliances.
• Mounting, cabling and protective devices: fix the modules to the roof and protect the system and the people around it.
• Meter and monitoring: the meter records what you buy from the grid and what you export; many systems show production in an app or website.
• Instant use: electricity you produce and use at the same moment saves the most, because you no longer buy it.
• Surplus: if you produce more than you use, the excess can be exported to the grid and, depending on the country and contract, valued in some way; it can also be stored in a battery if there is one.

Do not confuse solar photovoltaics, which produce electricity, with solar thermal, whose collectors heat a fluid for hot water or space heating. Both can share a roof, but this guide covers photovoltaics only.

How much does it cost to install solar panels on a home?

The price of a home system varies widely with the country, the year, the size, the roof and what the quote includes. That is why this guide does not give a national "average price": we found no official, up-to-date statistic on residential prices covering every market, and advertised figures often describe different systems. What helps is knowing which items make up the price and comparing quotes on the same basis. These are the usual items:

• Modules: number, rating of each one and model.
• Inverter: string inverter, microinverters or optimisers, depending on the design; with a battery it may be a hybrid inverter.
• Mounting structure: depends on the roof type (tiles, metal sheet, flat roof) and whether the modules need to be tilted.
• Cabling, electrical protection and monitoring.
• Labour and safety equipment: roof access, lifelines, scaffolding or lifts where needed.
• Design or technical report, permits and registration: local permits, registration and notifying the electricity company, depending on the country.
• Preliminary work: repairing the roof or reinforcing the structure if the technical survey requires it.
• Battery: optional; it clearly raises the investment.
• Taxes: VAT or other taxes depending on the country; check whether the price includes them.
• Financing cost: interest and fees if you pay with a loan or installer finance.

Do not confuse the price of a panel with the price of a complete system. Fraunhofer ISE estimates that in Germany modules account for only about one fifth of the investment in PV plants, and a smaller share in small rooftop systems, according to its report updated in August 2026. To compare offers, divide the total price including taxes by the installed peak capacity: you get euros per kilowatt-peak (€/kWp) or per watt-peak (€/Wp), the method also suggested by the US Department of Energy. A €5,000 quote for 4 kWp works out at €1,250/kWp; a €6,000 quote for 5 kWp, at €1,200/kWp. Even so, compare what each one includes.

How many solar panels does a house need?

The number of panels does not follow from the floor area of the home. It depends on how much electricity you use each year and at what times, how much each kilowatt-peak produces where you live, how much unshaded usable roof space you have and the applicable rules. Before talking about panels, get the units straight:

• W (watt) and kW (kilowatt): units of power, that is, how fast energy is produced or used at a given instant. 1 kW = 1,000 W.
• Wp and kWp (watt-peak and kilowatt-peak): the power of a module or system measured under standard laboratory conditions (1,000 W/m² of irradiance and 25 °C at the module, according to the PVGIS manual). It is for comparing equipment, not for knowing how much it will produce on your roof.
• kWh (kilowatt-hour): the unit of energy, the one on your bill. A 4 kWp system does not produce "4 kWh"; it produces a number of kWh per year that depends on the sun, orientation, temperature and losses.

For example, with 400 Wp modules, a 4 kWp system has 10 modules. If your daytime use is low, installing more panels than you can use raises the investment and, above all, the surplus, which is usually valued far below the electricity you no longer buy. More panels do not automatically mean more savings.

How much electricity can solar panels produce?

Annual output depends on many factors, which is why two systems with the same kWp can generate very different amounts:

• Solar radiation and location: some regions have far more resource than others.
• Season: output is much higher in summer than in winter.
• Orientation and tilt: in the northern hemisphere south-facing usually yields most, although east and west are also viable and spread output between morning and afternoon.
• Shading: from trees, buildings, chimneys or aerials; partial shade can reduce the output of several modules.
• Temperature: modules perform worse when they get very hot.
• System losses: cabling, inverter, dirt or snow; PVGIS suggests 14 % by default.
• Degradation: modules slowly lose power over the years.

For a first estimate you can use PVGIS, the free tool from the European Commission's Joint Research Centre. You enter the location, peak capacity, tilt, orientation and losses, and it returns average monthly and annual output. Its manual sets out its limits: the calculated horizon accounts for hills and mountains, not nearby shade from trees or buildings unless you upload your own horizon profile, and the result assumes all the energy is used or sent to the grid, without saying how much you will use at home. For this guide we ran two queries on 22 October 2026 with PVGIS 5.3, the PVGIS-SARAH3 radiation database (2005-2023), crystalline silicon, 14 % losses, calculated horizon and building-integrated mounting, the more cautious of the two options it offers:

• Madrid, 4 kWp, south-facing at a 30° tilt: about 6,160 kWh a year (6,163 kWh in the PVGIS output), from about 370 kWh in December to about 660 kWh in July.
• Oviedo, 3 kWp, east-facing at a 20° tilt: about 2,880 kWh a year (2,884 kWh in the PVGIS output), from about 100 kWh in December to about 350 kWh in July.

How solar savings are calculated

The most common mistake is to multiply all the annual output by the electricity price. The energy generated goes to different places, and each is worth a different amount:

• Electricity generated: everything the system produces in a period, for example a year.
• Electricity self-consumed: the part of that generation used in the home at the moment it is produced (or later, if there is a battery). Each self-consumed kWh avoids buying one from the grid, with all the variable charges on that kWh.
• Surplus electricity: the part not used at home and exported to the grid. Depending on the country and contract it may be worth nothing, be credited on the bill or be sold, almost always at a lower price than you pay to buy.

Generation = self-consumption + surplus. Two indicators help avoid confusion: the self-consumption rate is the share of output you use at home; the self-sufficiency rate is the share of your total consumption covered by the panels. They are not the same. In Germany, Fraunhofer ISE says households without a battery directly use between 20 % and 40 % of what they generate, depending on system size. To estimate your savings you need to know, at least:

• The electricity you stop buying and its full variable price (energy, variable network charges and levies, and taxes, depending on your tariff).
• How the surplus is valued and with what limits.
• The fixed charges on your bill, such as contracted capacity or standing charges, which generally do not fall because you have panels.
• The terms of your contract and any tariff change your supplier requires for self-consumption.

What is surplus compensation?

When the panels produce more than the home uses, the surplus can be handled in several ways depending on the country and contract: stopping it from leaving the home with an export-limiting device, crediting it as a discount on the bill, selling it like any generator or giving it to the grid unpaid. None of these options by itself guarantees a cash income.

Spain as an example: simplified compensation

In Spain, Royal Decree 244/2019 (consolidated text, last update published on 21 March 2026) distinguishes self-consumption without surplus, with an export-limiting device, from self-consumption with surplus, which can be under compensation or not under compensation. In the latter case the surplus is sold on the market and the owner takes on the obligations of a generator. The simplified compensation in Article 14 works like this:

• It is only available with renewable sources, a total generating capacity of up to 100 kW and a compensation contract, among other conditions in Article 4.
• With a free-market supplier, the energy bought and the surplus are valued at the hourly price agreed; with the regulated small-consumer tariff (PVPC), the surplus is valued at the average hourly market price minus imbalance costs.
• The value of the surplus can never exceed the value of the energy bought from the grid in the billing period, which cannot be longer than one month. The bill cannot go negative because of it. That limit is not a fixed tariff: it depends on what the energy bought costs under each contract.
• According to the IDAE's frequently asked questions, compensation applies to the energy charge: it does not reduce the capacity charge or network tolls. Anything above one month's limit is not carried over to the next.
• Anyone using compensation cannot sell that surplus through another route at the same time.

Outside Spain: different mechanisms

Each country has its own system, and the names are misleading: US net metering, the German feed-in tariff and Spanish simplified compensation are not equivalent. Some examples with their official source, valid on the date consulted and subject to change:

• United Kingdom (Great Britain): under the Smart Export Guarantee, certain suppliers pay for exported electricity; each sets its own rate and terms, which must always be above zero.
• Germany: the Bundesnetzagentur publishes feed-in payments by commissioning date and capacity; the current rules apply until 31 December 2026, and their successor was going through parliament when we checked.
• Italy: the GSE's Ritiro Dedicato lets producers sell the energy they feed into the grid to the GSE at a price per kWh, as an alternative to the open market.
• United States: net metering depends on each state and utility, according to the Department of Energy; the DSIRE database lists policies and incentives by ZIP code.
• Other countries: check the website of the national energy regulator, ministry or energy agency and ask your supplier for the terms in writing.

How long do solar panels take to pay back?

The most widely used measure is the simple payback period:

Simple payback period (years) = net initial investment ÷ estimated net annual savings

• Initial investment: the total price including taxes of everything needed, including preliminary work, permits and registration.
• Net investment: the initial investment minus grants already awarded and tax incentives you can prove. A grant applied for but not yet decided should not be deducted.
• Gross annual savings: the value of self-consumption plus the value of the surplus, with its limits.
• Annual operating and maintenance costs: inspections, insurance, monitoring and minor repairs. Fraunhofer ISE puts the annual operating costs of PV plants at about 1-2 % of the investment and uses 1 % in its small-system example.
• Net annual savings: gross savings minus annual costs.

This calculation leaves out the time value of money, inflation, future electricity prices, module degradation, inverter replacement, faults, regulatory changes, financing costs and the residual value of the system. So it is not the same as a full financial return, which is analysed with measures such as NPV or IRR. The IDAE estimates 6 to 10 years for an average four-person household in its 5-step guide; that is a general reference for Spain, not the period for your case. If you will finance the system, add the interest: the guide to nominal rate and APR explains how to compare the real cost of a loan.

Three worked payback examples

These three scenarios are illustrative, not real offers or averages. They use the output from this guide's PVGIS queries and hypothetical economic assumptions expressed in euros. As we do not have real hourly consumption data, the split between self-consumption and surplus is a stated assumption, checked month by month against the PVGIS monthly output. Common assumptions:

• Value of each self-consumed kWh: €0.18, the full variable price no longer paid.
• Value of each compensated kWh of surplus: €0.04.
• Compensation limit: we assume the energy part of each kWh bought from the grid is worth €0.10; this is a hypothetical value, not a regulated tariff. Each month, the value of the surplus cannot exceed that amount multiplied by the kWh bought that month, which is how the monthly limit in Royal Decree 244/2019 works.
• Self-consumption each month: the lower of two values: 45 % of that month's output or the home's daylight-hours consumption that month. The 45 % is our own assumption about how much output coincides with use; PVGIS does not calculate it, it only estimates output.
• Annual operating and maintenance costs: 1 % of the investment.
• No battery, no grants or tax deductions, and paid in cash. For simplicity, all amounts, including the investment, are treated as final, taxes included, and prices stay constant; on a real bill, compensation is deducted before taxes are applied.

Scenario A: a home well suited to self-consumption

A house in Madrid with a south-facing roof, no significant shade and someone at home during the day. It uses 5,000 kWh a year, 55 % of it (2,750 kWh) during daylight hours. It installs 4 kWp for €5,000 (€1,250/kWp).

• Generation: 6,160 kWh a year.
• Self-consumption: 2,520 kWh (41 % of output, covering 50 % of consumption), never above daytime demand in any month.
• Surplus: 3,640 kWh. The monthly limit never applies.
• Value of self-consumption: 2,520 × €0.18 = €453.60.
• Value of the surplus: 3,640 × €0.04 = €145.60.
• Gross savings: €599.20; annual costs: €50; net savings: €549.20 a year.
• Simple payback period: 5,000 ÷ 549.20 = about 9.1 years.

Scenario B: a home that uses most electricity at night

Same house, same system and same output, but the people living there are out all day: only 25 % of their 5,000 kWh a year (1,250 kWh) is used during daylight hours. Output does not change; where it goes does.

• Generation: 6,160 kWh a year.
• Self-consumption: 1,250 kWh (20 % of output and 25 % of consumption), capped by low daytime demand.
• Surplus: 4,910 kWh. Because the home buys a lot of electricity at night, the monthly limit does not apply here either.
• Value of self-consumption: 1,250 × €0.18 = €225.00.
• Value of the surplus: 4,910 × €0.04 = €196.40.
• Gross savings: €421.40; annual costs: €50; net savings: €371.40 a year.
• Simple payback period: 5,000 ÷ 371.40 = about 13.5 years.

Scenario C: an unfavourable installation

A house in Oviedo whose only available roof face points east, with low consumption (2,000 kWh a year, 40 % during daylight hours) and a difficult roof that needs scaffolding and special mounting. It installs 3 kWp for €6,000 (€2,000/kWp). PVGIS does not include nearby shade: if there were any, real output would be even lower.

• Generation: 2,880 kWh a year.
• Self-consumption: 750 kWh (26 % of output and 37.5 % of consumption).
• Surplus: 2,130 kWh. Without a limit it would be worth 2,130 × €0.04 = €85.20, but in the sunniest months the home buys so little electricity that the monthly limit cuts compensation to €81.80.
• Value of self-consumption: 750 × €0.18 = €135.00.
• Gross savings: 135.00 + 81.80 = €216.80; annual costs: €60; net savings: €156.80 a year.
• Simple payback period: 6,000 ÷ 156.80 = about 38 years, longer than the usual module performance warranties (25-30 years).

Comparing the three scenarios

• A, favourable: investment €5,000; generation 6,160 kWh; self-consumption 2,520 kWh; surplus 3,640 kWh; net savings €549.20/year; simple payback about 9.1 years. Main limitation: it relies on daytime use continuing.
• B, night-time use: investment €5,000; generation 6,160 kWh; self-consumption 1,250 kWh; surplus 4,910 kWh; net savings €371.40/year; simple payback about 13.5 years. Main limitation: most of the energy is valued as surplus.
• C, unfavourable: investment €6,000; generation 2,880 kWh; self-consumption 750 kWh; surplus 2,130 kWh; net savings €156.80/year; simple payback about 38 years. Main limitation: little useful sun, low consumption and a high cost per kWp.

Solar panels with or without a battery

A physical battery stores part of the daytime surplus to use later, for example at night. That raises self-consumption, but also the investment, and it is never fully efficient: some energy is always lost when charging and discharging, as the US Department of Energy notes. It helps to separate three things:

• Direct self-consumption: you use PV electricity at the moment it is produced.
• Self-consumption through a battery: you later use electricity you stored earlier, with some losses along the way.
• Surplus compensation: an economic or contractual mechanism that values the energy sent to the grid, where one exists; it does not store energy.

A battery makes economic sense when what you gain on each kWh shifted exceeds what it costs to shift it. In scenario B, each kWh that moves from surplus to self-consumption is worth €0.18 instead of €0.04. Suppose, hypothetically, that a battery delivers 1,000 usable kWh a year and, with a round-trip efficiency of 90 %, needs 1,100 kWh of surplus to do so: the extra gross saving would be 1,000 × 0.18 − 1,100 × 0.04 = €136 a year. That is not a return: the investment in the battery, its maintenance, its loss of capacity over the years and its replacement still have to be subtracted. If the installed battery costs more than €136 for each year of useful life you can expect from it, it does not pay for itself under those assumptions. A battery does not always improve the return; there can be other reasons for one, such as backup.

Lifespan, maintenance and replacements

Panels do not switch off the day their warranty ends, but they are not everlasting or free of costs either. The IDAE says the useful life of these systems can reach 30 years. It is worth distinguishing:

• Product warranty: covers manufacturing defects in the module, inverter or battery for a period; each manufacturer sets its own.
• Performance warranty: guarantees that modules will keep a minimum percentage of their power. According to Fraunhofer ISE, manufacturers usually guarantee a maximum loss of 10-15 % over 25-30 years.
• Actual degradation: in a Fraunhofer ISE study of 44 quality-checked rooftop systems, modules lost on average about 0.15 % of their power a year; the institute considers an assumed 0.5 % annual loss of output to be cautious. Manufacturing or installation defects can speed it up.
• Inverter: it usually lasts less than the modules, so it is reasonable to plan for a replacement during the system's life; ask for its warranty and a cost estimate.
• Battery: its usable capacity falls with use and age; check the warranty in years and in cycles or energy throughput.
• Maintenance: checks of protective devices and connections, watching the monitoring to spot drops in output and, when needed, cleaning by people who work safely.
• Insurance and repairs: check whether your home insurance covers the system and what happens if it has to be removed to repair the roof.

Grants, subsidies and tax incentives

Incentives change often, depend on where you live and have limited deadlines and funds. Do not count on any until you have checked at the official source that it is open, that you qualify and, better still, that it has been awarded. The situation in Spain on 22 October 2026:

• National self-consumption programme under the Recovery Plan (RD 477/2021): according to the IDAE, regional governments accepted applications until 31 December 2023. Do not present it as an incentive available today.
• Income tax (IRPF) deduction for installing renewable self-consumption: the sixty-second additional provision of the Income Tax Act, introduced by Royal Decree-law 7/2026, allows a deduction of 10 % of the amounts paid to install renewable self-consumption, which may include storage, in a property you own, or 20 % if you own a home in a predominantly residential building where the system is installed. The maximum base is €5,000 a year, so the maximum deduction is €500 at 10 % or €1,000 at 20 %, and it is subtracted from the state share of the tax liability, not from the whole tax. Only payments and installations from 1 January to 31 December 2026 count, and it applies in the year the installation is completed. It requires payment by means other than cash, deducting grants, having the permits and the electrical installation certificate (CIE), and it does not apply to systems used for an economic activity. The same installation cannot claim both the 10 % and the 20 %. The Spanish Tax Agency summarises it the same way.
• General deduction for work improving a home's energy efficiency (fiftieth additional provision): a different regime, at 20 %, 40 % or 60 % depending on the work, which requires before-and-after energy performance certificates proving a minimum improvement; its deadlines run to 31 December 2026 for homes and 31 December 2027 for buildings. The law does not allow this deduction and the self-consumption one to be applied to the same installation in the same property: you have to choose one. Confirm with a tax adviser or the Spanish Tax Agency before counting on either.
• Municipal tax relief: the Local Finance Act lets each council, if it approves it in its tax bylaw, grant a reduction of up to 50 % in property tax (IBI) and up to 95 % in the construction tax (ICIO) for systems that use solar energy. They are optional: they exist only where the council has approved them, with its own percentage, duration and conditions.
• Autonomous communities: they may run their own grants or deductions in the regional part of income tax; check with the competent body in yours.

Outside Spain we do not attempt a catalogue of incentives, because it would quickly go out of date. Look on the website of your country's energy agency or ministry, your region and your local council; in the United States, the Department of Energy points to DSIRE.

Solar panels on a block of flats

Living in a flat does not necessarily rule out self-consumption. In Spain, the IDAE describes several options in its guide for owners' associations:

• Individual self-consumption: a single associated consumer, for example the supply for shared services (lift, lighting) or a single resident using a system on the shared roof.
• Collective self-consumption: several consumers share all the energy generated according to coefficients signed by everyone; they can be fixed or vary by hour, and must add up to 1.
• Owners' meeting approval: a system on shared elements needs approval from the owners' meeting under Article 17 of the Spanish Horizontal Property Act, with different majorities depending on cost and use; check with the property manager.
• Distance and connection: Spanish rules allow nearby systems to be associated if they meet one of the conditions in Article 3 of Royal Decree 244/2019: connection to the internal wiring, to the low-voltage network of the same transformer substation, within 500 m of the consumers (measured on plan between the meters) or on the same cadastral reference. Only PV or wind systems of up to 5 MW connected through the transmission or distribution networks may be up to 5,000 m away.
• Physical limits: a shared roof is often small for the number of homes, may be shaded by other buildings and needs a clear split of costs, maintenance and responsibilities.

These are Spanish rules; in other countries the majorities, distances and sharing mechanisms differ. In any case, no owner can put panels on a shared roof without the relevant agreement and procedures. Collective projects usually need technical and often legal advice.

When are solar panels not worth it?

None of these situations automatically rules out a system, but all of them call for more careful numbers:

• Very low electricity use: there is little to save and almost all the output ends up as surplus.
• An unsuitable roof or one that will soon need repairs: removing and refitting panels costs money; if the roof needs work, it is better to do it first.
• Significant shading: trees, buildings or features on the roof itself can cut output sharply.
• High adaptation costs: special mounting, reinforcement, scaffolding or long cable runs.
• A planned move: if you will sell or leave the home within a few years, you may not recover the investment.
• Doubts over the right to use the roof: tenants, shared roofs or easements require permission and agreements.
• An oversized system: more capacity than you can use mostly increases the surplus.
• Little overlap between production and consumption and poorly valued surplus.
• Expensive finance: interest can eat up much of the saving.
• Misunderstood incentives and quotes with missing costs: permits, registration, VAT or mounting that appear later.

Before installing, or instead of it, you can:

• Cut unnecessary use and review your contracted capacity.
• Improve insulation if much of your spending goes on heating or cooling.
• Shift use to cheaper hours according to your tariff.
• Ask for an independent technical assessment of your roof and consumption.
• Compare several quotes using the same criteria.
• Consider collective self-consumption or a nearby system if your roof is unsuitable.

How to compare installer quotes

The IDAE recommends getting several quotes, at least three for owners' associations. The cheapest is not always the best: compare what each includes. Checklist:

1. Total capacity in kWp, number of modules, rating of each and, if given, make and model.
2. Inverter: type, rating, make and model, and whether it can take a battery in the future.
3. Mounting suited to your roof and how the roof is kept watertight.
4. Electrical protection, cabling and monitoring included.
5. Configuration: with or without surplus, compensation, sale or another arrangement.
6. Estimated annual output in kWh and the simulation assumptions: tool, orientation, tilt, shading and losses.
7. Estimated self-consumption and surplus based on your consumption profile, not a generic percentage.
8. Product and performance warranties for modules, inverter and battery, and a workmanship warranty.
9. Paperwork, permits, registration and connection: who handles them and whether they are included.
10. Maintenance: what it includes, how often and what it costs after the first year.
11. Total price including taxes and price per kWp.
12. Financing: APR, fees, term and whether it is tied to other contracts.
13. Installation and commissioning timescales.
14. Exclusions: roof work, reinforcement, scaffolding, trenches or changes to the consumer unit.

Installation safety

This guide is not an installation manual. Fitting panels involves working at height and with electricity, and grid connection is regulated. In Spain, the IDAE says the work must be carried out by an authorised installation company, which files the system's documentation with the regional government; other countries have their own qualifications and certifications. Before installation, a competent professional should check:

• The condition of the roof and the structure's capacity to carry the weight and wind loads.
• The risks of working at height and the collective or personal protection needed.
• Electrical safety, protective devices and the connection to the home's wiring and to the grid.
• Local permits and the procedures with the authorities and the electricity company.

Frequently asked questions

How much does it cost to put solar panels on a house?

It depends on the country, capacity, roof, taxes and whether a battery is included, so there is no single reliable price. Ask for itemised quotes, compare them in €/kWp including taxes and check which items each includes; in this guide's examples we assumed €1,250/kWp on a simple roof and €2,000/kWp on a difficult one.

How much can I save per month with solar panels?

It depends on how much you self-consume and how your surplus is valued, not on the total you generate. In this guide's examples net savings range from about €46 a month (scenario A) to about €31 (B) and about €13 (C), and you save considerably more in summer than in winter. You still pay the fixed charges on the bill.

Do they work in winter or when it is cloudy?

Yes, but they produce less. In this guide's Madrid simulation, December generates about 370 kWh and July about 660 kWh; in the Oviedo one, about 100 kWh and about 350 kWh. Cloud reduces output, and if snow covers the modules it can stop until they clear.

Is a battery worth it?

Only if the extra saving it generates over its useful life exceeds its cost. It helps most when you have a lot of poorly valued surplus and use electricity at night, as in scenario B, but it raises the investment and loses some energy. Ask for the quote to calculate the result with and without a battery.

Do solar panels work during a power cut?

Not necessarily. Many grid-connected systems stop powering the home during an outage, even with a battery. Only a system designed and approved to operate isolated from the grid can keep some circuits running; ask before you sign.

Can solar panels be installed on a block of flats?

Yes, in many cases, through individual self-consumption for shared services or a single resident, or collective self-consumption with an agreed split. In Spain the owners' meeting must agree; in other countries, local rules apply.

Sources

• IDAE: ¿Qué es el autoconsumo? and Guías técnicas sobre autoconsumo, consulted on 22/10/2026.
• IDAE: Guía #05 pasos para convertirse en autoconsumidor and Guía #05 pasos para autoconsumo en comunidades de propietarios, 2023 editions updated in 2026.
• IDAE: 99 preguntas frecuentes sobre autoconsumo and RD 477/2021 grants.
• BOE: Real Decreto 244/2019, consolidated text, last update published on 21/03/2026.
• BOE: Ley 35/2006 del IRPF, consolidated text, fiftieth and sixty-second additional provisions; Real Decreto-ley 7/2026; Spanish Tax Agency: changes introduced by Royal Decree-law 7/2026; and Ley reguladora de las Haciendas Locales, consulted on 22/10/2026.
• European Commission, Joint Research Centre: PVGIS and PVGIS 5 user manual; simulations run on 22/10/2026.
• US Department of Energy: Homeowner's Guide to Solar, Will I Save Money with Solar Energy?, Choosing a Solar Installer, Solar Energy and Storage Basics, The Road to Resilience with Rooftop Solar and Solar and Resilience Basics.
• Fraunhofer ISE: Aktuelle Fakten zur Photovoltaik in Deutschland, version of 20/08/2026.
• Ofgem: Smart Export Guarantee, Bundesnetzagentur: EEG-Förderung, GSE: Ritiro Dedicato and DSIRE, consulted on 22/10/2026.