Frequently asked questions about solar panels and self-consumption

It is the ability of one or more consumers to generate, manage and consume energy in the same location or remotely, whether with or without energy accumulation. Each kWh produced and self-consumed is 1 kWh less that we must buy from the electricity company with its corresponding savings on the electricity bill.

Solar panels generate direct current that is received by the inverter, which transforms it into the alternating current that we consume at home.

We inject the generated solar energy (in most cases) directly into the main electrical panel of the house, so that if at a given time we are generating 3 kWh and consume 4 kWh, then the first 3 kWh of consumption will come from the solar panels we will buy the kWh that remains to complete consumption from the electricity company.

And also the other way around, if at a given hour we are generating 3 kWh, and we are only consuming 2 kWh, then the entire consumption will come from the solar panels and the excess solar kWh will be sent to the grid.

For this kWh that we send to the grid, the electricity company will apply a discount to our electricity bill (compensation).

In those self-consumption facilities with less than 100 kW of power and that are connected to the internal network of any of the consumers associated with the generation facility, the electricity company will value the surpluses (leftovers) that we send to the distribution network in accordance which is called simplified compensation mechanism.

Of the energy produced by the photovoltaic installation, the energy that cannot be self-consumed at the moment (solar surplus) will go to the electrical grid and the bidirectional meter of the marketing company will count hourly the total energy sent (exported) into the distribution grid.

Each electricity marketing company values the kWh sent to the network at a different price, adding their value during the month.

At the end of the month, when we receive the invoice, we will see a discount line with the total economic value of the kWh sent to the grid.

The electricity bill can never be negative, and therefore if the installation has many surpluses, a part of these may not be able to be valued and may be lost.

It is important to keep in mind that the value they give us for the surplus is always lower than the value we pay for the electricity consumed, and therefore we will always have maximum profitability and lower payback with installations with little surplus.

However, if we try to make an installation without surpluses, the resulting installation may be very small, and therefore the savings in absolute value will also be lower.

Therefore, the most appropriate thing is always to achieve an optimal balance between profitability (small installation with little surplus) and savings (larger installation with more surplus) that satisfies the client's needs, each client is different.

If we install a battery we reach the maximum value for each kWh generated, since we value all the kWh generated at the price we buy electricity at home. To achieve this maximum value, it is necessary to invest in the battery, which generally represents an extra cost of between 60% and 70% compared to the installation without a battery. This extra cost can be significantly reduced with the grants and subsidies currently available, which are especially focused on storage systems.

On the contrary, if we do not install the battery, the surpluses that would go to the battery will be sent to the electrical grid and will be compensated/valued at a lower price than if we had saved them. The advantage of not installing the battery is that you save that 60% - 70% extra cost.

If we think about buying a battery in economic terms, the amortization of the installation may be longer, but in any case the economic factor is not always decisive, since there are many people who buy batteries from us because they want to achieve maximum autonomy with respect to the electricity company.

Furthermore, we must not forget that as more solar systems are installed, the price of electricity during the day will fall and at night it will be more expensive, and therefore it will be more profitable to install batteries.

There are other storage systems to store surpluses. We have surplus diverters, which when they detect that solar generation is lower than consumption, they divert the surplus to an electrical resistance located inside a hot water tank, so that the water is preheated coming from the street before reaching the boiler/water heater and thus the thermal jump necessary to heat it is reduced.

Batteries store energy in the form of chemical energy and DHW accumulators in the form of thermal energy.

Another solution for those who have an electric car and a possible charging point is to install an electric vehicle charger (EVC) that allows them to take advantage of solar surpluses.

A solar installation currently has a proven lifespan of more than 25 years. Consider that a solar installation has no moving mechanical parts subject to wear, nor circulating fluids that cause overpressure as happens with solar thermal energy. Therefore, if the installation has been well designed, it is very reasonable to expect a useful life of more than 25 years.

Modules gradually degrade over time and lose production capacity; however, manufacturers offer a minimum production warranty of 80% at 25 years — that is, they guarantee that after 25 years, the solar panels will produce at least 80% of what they produced on the first day.

In addition, panels have a product warranty of at least 12 years against manufacturing defects. Premium solutions are also available, such as SunPower Performance panels, which offer a triple 30-year warranty (product, power output and service).

Current inverters have a useful life of more than 15 years, and the inverters we offer come with a 10-year warranty.

Battery: the most common batteries in solar installations are lithium iron phosphate (LiFePO4) and usually have a 10-year warranty and a useful life of more than 6,000 cycles (16 years).

The mounting structures we offer generally have a 10-year warranty.

In addition, as an installation company, we offer a 5-year installation warranty, far beyond the 2 years legally required that most installation companies offer.

The best maintenance that your solar installation can have is to have a good monitoring system that allows you to know that your solar installation is producing correctly at all times.

The only maintenance task that may be advisable is to try to clean the solar panels from time to time (mud and bird droppings). In any case, only clean the panels if access is safe enough.

Generally, rainwater already cleans the panels since a 5° inclination of the panels is more than enough for the water to remove dirt from the solar modules. Residential installations typically have between 10° and 15°.

Rather than paying in advance for a maintenance service that will eat up part of the annual savings, we recommend keeping a good track of production and, if necessary, hiring our after-sales service.

We are currently preparing a premium monitoring solution that will allow us to carefully monitor production and set a few alarms that will alert us of any anomaly.

Standard self-consumption installations automatically disconnect during a power outage for safety reasons. Regulations require solar installations to stop working when they no longer detect voltage from the grid, in order to protect operators who may be working on the distribution lines.

If you need coverage during power cuts, the solution is to include a battery with backup function. This combination allows your installation to keep powering essential circuits of the home (fridge, lighting, router, alarm) even during a supply outage.

Backup batteries are sized based on real energy needs and provide greater energy independence and security against unexpected events.

To learn more, on our blog we explain how solar panels and batteries improve energy resilience against power outages.

Sí, hi ha solucions de backup que permeten que la instal·lació solar continuï funcionant fins i tot quan es produeix un tall de llum. Aquestes solucions combinen l'ús de bateries amb un sistema de backup que assegura que la teva instal·lació fotovoltaica pugui operar de manera autònoma, desconnectant-se de la xarxa elèctrica de forma segura.

Instal·lar un sistema de backup et dona la tranquil·litat de mantenir serveis essencials com la nevera, la il·luminació o el router funcionant durant un tall de subministrament. Avui dia les bateries són cada cop més accessibles i, a més, es poden dimensionar perquè s'adaptin a les teves necessitats reals d'energia.

Tot i que la inversió inicial és més gran, tenir un backup ofereix una major independència energètica i seguretat davant d'imprevistos. La nostra recomanació és valorar aquesta opció especialment si vius en zones on els talls de llum, encara que siguin puntuals, et poden causar inconvenients. Nosaltres podem assessorar-te per dissenyar un sistema a mida, assegurant el millor equilibri entre cost i benefici.

A standard single-family home usually needs between 8 and 12 panels of 450 W (3.6-5.4 kWp) to cover a typical consumption of 3,500-5,000 kWh per year. If you have an air-source heat pump, electric vehicle or swimming pool, the range increases to 14-22 panels.

At SolarTradex we size each installation based on your actual consumption and your future projection. We analyse your bill, roof orientation, shading, habits and medium-term plans to avoid unnecessary oversizing.

It makes sense if you're clear you'll consume more in the future, but we should remember that adding 4 more panels later will always cost significantly more than installing them now.

Bear in mind that home electrification (aerothermia, electric car, induction cooking, swimming pool) will increase your electricity consumption in the coming years, so sizing the inverter properly from the start is a profitable long-term decision.

If you are planning any of these changes, it's important to tell us your forecast before sizing the installation. You can request your solar panel quote and we will prepare a proposal that takes into account your current and future consumption.

No, if the installation is done correctly. It's one of the most common concerns before installing solar panels, but with the right technique, leaks are completely avoidable.

How the panels are anchored to the roof: using the appropriate drill bit, the tile is pierced at its highest point, reaching the structural part of the roof underneath (wooden boards or concrete). It's in this structural layer where the screws that support the aluminium mounting structure and solar panels are fastened.

The tiles are only crossed by the fastening screws, which include a flat rubber gasket that is tightened with a nut over the hole, providing the necessary waterproofing to prevent any potential leaks.

In addition, since all the drilling points are located below the panels —which act as a protective cover— and at the highest part of the tiles (where water never flows), the anchor points don't even get wet.

If your solar installation is up to 15 kW, in most cases you will not have to apply for a connection permit.

Important: the permit is always requested from the distribution company, which in Catalonia and the Balearic Islands is Endesa Distribución (e-Distribución / i-DE). It is a technical procedure, not a commercial one: even if you have your electricity contracted with another retailer (Som Energia, Holaluz, Naturgy, etc.), the connection procedures always go through the distribution company.

However, if your installation is not located on urbanised land with the basic amenities and services required by planning regulations, it will be necessary to request a connection study from the distribution company, which has a cost of €100 + VAT.

In addition, in these cases it will also be necessary to arrange a technical access contract with the distribution company, which regulates the technical conditions for connection to the distribution grid. This is not an economic contract.

Virtual batteries are a mechanism whereby the electricity retailer manages the solar surpluses you send to the grid and applies an economic compensation on your subsequent bills, sometimes allowing you to assign the surplus to different supply points.

At first they seem an attractive idea, since they allow you to take advantage of surplus kWh without investing in a physical battery.

However, today most retailers have introduced significant limits: compensated amounts cannot exceed the cost of the energy billed (there is never a credit balance in cash), and the price at which they value the surplus is progressively decreasing due to solar oversupply during daytime hours (the "duck curve" phenomenon).

In addition, the current framework (RDL 7/2026) and the active grants and subsidies (IRPF, CAE, FACTOR 2026 in the Balearic Islands) are especially boosting systems with physical batteries, which provide real autonomy and maximum valorisation of the surpluses.

Therefore, virtual batteries are a useful short-term solution, but in the medium-long term, the future of energy storage will lie with physical batteries.

A collective self-consumption installation is the sum of n individual installations that share a series of common infrastructures: a single project, a single wiring, a single inverter, a single legalisation and processing.

For this reason, all participants must sign a sharing agreement that establishes the % of the installation held by each participant.

From here, it must be understood that sharing energy is a virtual phenomenon in which we don't actually know where the electrons go physically.

For this reason, in a collective self-consumption installation it will be necessary to install a generation meter that will read and inform the distribution company of the total energy generated.

The distribution company will apply the sharing coefficients from the agreement and allocate to each participant the corresponding share of generation. From here it will compare the generation with the consumption read by each participant's consumption meters and carry out the corresponding balance, ultimately billing each one the difference between their consumption and their generation. If this difference is less than 0, the corresponding surplus will be applied.

Currently, the maximum straight-line distance in the orthogonal plane between the generation meter and the consumption meter is 5 km. This limit was extended by Royal Decree-Law 7/2026, which updated the previous 2 km cap established by RD 244/2019.

Energy can be shared both in low voltage (LV) and in medium voltage (MV).

In addition to the distance criterion, sharing is also enabled if participants are connected to the same low-voltage line from the same transformation centre, or if the first 14 digits of the cadastral reference match (shared buildings or plots).

Sharing only the surplus of an individual installation is not an option contemplated by the regulations. When an installation is individual, the surplus energy is automatically fed into the grid and cannot be selectively redirected to neighbours.

That said, there are two legal routes for your installation to also benefit your neighbours:

• Transforming it into a collective self-consumption installation: in this case you will share all the energy generated (both self-consumed and surplus), not just the surplus. The sharing percentages are agreed in advance between the participants through a sharing agreement.
• Opting for the simplified surplus compensation scheme: the surplus is fed into the grid and your electricity retailer discounts its value on your bill. You don't physically share the energy with specific neighbours, but you contribute to the system and maximise the return on your installation.

Facing modules to the north will always be the last option, but if it is not possible to face them south because we do not have space, or because we need more power to cover consumption and we do not have east-west options either, then we will face the panels north without any problem.

It should be noted that panels facing north in Catalonia produce approximately 10% less than modules facing south in Germany.

In any case, at SolarTradex we design every residential installation making the most of the orientation and surface available on your roof.

At SolarTradex it is a very bad option, for the following reasons:

Aesthetics. We need to make PV sexy, and seeing a house with raised panels on a sloping tile roof is just the opposite. There are aesthetically refined options such as SunPower Performance panels with a full-black finish.

It is dangerous: we are experiencing more and more extreme weather conditions, and placing elevated panels on a sloping roof only increases the wind load and plays with fire, so that the installation flies away on the day you least expect it.

The Urban Planning Law does not allow it, since the urban planning of the municipality where they are installed would have to be modified. Installation on the roof of buildings and other auxiliary constructions, including car park pergolas, is only permitted when the installations do not exceed one meter in height from the flat roof or, in the case of a sloping roof, when the collectors or panels are located attached in parallel.

If we want to maximise solar generation, today it is much more profitable and safe to install a couple more solar panels in a coplanar arrangement facing east or west, since the price of solar panels has dropped very significantly and the cost of the structure will also be cheaper.

Yes it is possible, but not really wise. If you want to disconnect, you will have to size the installation to guarantee at least 3 days of autonomy, which means making the installation bigger and installing batteries large enough to store energy for 3 days.

In addition, you will need to install a backup generator in case, for example, we go through a week of bad weather in winter without being able to charge the batteries.

Obviously this is much more expensive than setting up a grid-tied self-consumption installation.

In addition, having an off-grid installation means always keeping an eye on consumption and battery charge, which goes against comfort: you can't just come home and switch on the heating or air conditioning whenever you feel like it, or disconnect without a second thought.

This is a very common question asked by anyone considering installing solar panels at home, and the answer is yes, except in exceptional cases. Most photovoltaic panels on the market today are manufactured to comply with a specific standard for high-impact resistance on the glass.

They use tempered glass, thermally processed to achieve greater resistance than conventional glass. They must pass hail impact tests (Hail test) that, according to the IEC 61215 standard, require them to withstand impacts from hailstones of different diameters and at different speeds.

That said, we are increasingly experiencing more extreme weather events, which means it cannot be guaranteed that if hail falls that is larger or faster than usual, the panels will not break. One example was the historic hailstorm on the afternoon of 30 August 2022 in the Baix Empordà (Catalonia), with hailstones of up to 10 cm in diameter.

In this sense, there are premium solutions such as SunPower Performance panels, certified to withstand hail impacts of up to 45 mm in diameter — well above the standard market benchmark of 25 mm.

The most advisable option is to insure the solar installation beyond your home insurance, protecting it against these extreme wind and/or hail events.

In cases of this type of disaster, insurance often will not cover the damage either if the Government declares a catastrophic zone; in that case, the Insurance Compensation Consortium (Consorcio de Compensación de Seguros) will take charge. However, for this to happen, you must have an active insurance policy.

Communal rooftops are not the private property of the top-floor neighbour; they belong to the community of residents. The regulations to follow depend on the territory:

In Catalonia (Catalan Civil Code):

• Both for individual and community-use installations on the common roof, it is necessary to request permission from the community.
• The owner must call a meeting, include the request on the agenda, and obtain approval by simple majority of those present.

In the Balearic Islands (Spanish Horizontal Property Law):

• Individual self-consumption in a private area (private terrace, private courtyard): no permission or notification required.
• Individual self-consumption on the communal roof: a prior notification to the community president is sufficient (art. 17.5 LPH). No meeting needs to be called.
• Collective self-consumption: requires approval by one third of the owners representing one third of the participation quotas (art. 17.2 LPH).

In both cases, the thresholds are designed to facilitate the energy transition and prevent individual or collective initiatives from being blocked. You can see real examples in our collective self-consumption projects. If you need help preparing the proposal to present at the meeting or the notification template, contact our team: we will support you throughout the process.

The VAT law allows a 10% VAT rate to be applied to renovation and repair works.

A photovoltaic solar installation can be considered a renovation or repair work if, and only if, all of the following conditions are met:

• The recipient of the work is someone who uses the home for private use, or a residential owners' community.
• The recipient cannot act as a business or professional.
• The construction of the home was completed at least two years earlier.
• The cost of the materials purchased by the installer does not exceed 40% of the total cost of the works.

For this reason, we always request a signed statement from our clients in order to apply this 10% rate.

This 10% VAT rate is compatible with other tax advantages and active grants such as the IRPF deductions, the CAE system and other current grant programmes.

Lastly, we can also apply the 10% VAT rate to self-promoters (private individuals who build or renovate their own home).

In photovoltaics, as in real life, size is not the most important thing…

What really makes a difference is efficiency, which is the ratio between the panel's power output and its surface area (W/m²). A panel with higher power output and larger size can be less efficient than a smaller one if its W/m² ratio is higher.

The more efficient the panel, the more kWp you can install in a given surface area — something especially important on roofs with limited space.

The panels we work with at SolarTradex are positioned in the high-efficiency segment of the market, which ensures making the most of every square meter of your roof.

And if you are looking for the maximum efficiency available, there are premium solutions such as SunPower Performance panels, with efficiency above 22.5% and a triple 30-year warranty (product, power output and service).

Permanent shading, even if it only affects part of a panel, has a fairly significant impact on the production of the solar array.

Solar panels are connected in strings, in the same way that within a single panel the different solar cells are also connected in 3 or 4 strings that join at the top of the panel (currently some panels have the connection point in the central part).

These strings can be imagined as pipes through which water flows. If a shadow affects only one cell, water will not circulate through any of the cells connected in that string within the panel.

And if that panel has 4 strings, then only 75% of the water will reach the top of the panel, and this panel will only pass 75% of the water to the next panel connected in the string. As a result, only 75% of the water will reach the end of the string — all because of a single shaded cell.

In short, every shadow matters and it is worth minimising them even when they seem small or only affect part of a single panel. There are panels with specific designs that minimise this issue, such as SunPower Performance panels, which use cells cut to a third and parallel circuits to reduce the impact of shading to a minimum.

Installing microinverters can be a very good option if you have significant shading on your installation.

Working with microinverters means that shadows on some panels do not affect the rest; however, if you do not have shading, you will pay a premium for the installation and it will perform just as well as without microinverters.

If you install microinverters and one of them fails, you will not lose all of the production as would happen if you worked with a single central inverter; but, on the other hand, you will have a much higher chance of a microinverter failure than if you worked with a single central inverter.

Furthermore, if a microinverter fails, you will need to climb onto the roof to repair it and dismantle the corresponding panel, so the repair or replacement cost will be much higher.

An alternative to microinverters for managing shading are SunPower Performance panels, which use cells cut to a third and parallel circuits to minimise the impact of shading without the need to install microinverters.

SunPower Performance solar panels stand out for their advanced technology and robust construction. Their key features include:

• N-type TOPCon cell technology: they use silicon doped with phosphorus, with a special layer that reduces energy losses.
• Shingled cell design: the cells overlap to make the most of the panel's surface, and in case of partial shading, the panel continues to produce energy in other areas.
• Flexible connections: they prevent the cells from breaking or microfissures from forming, a common problem in other panels caused by temperature changes.
• Glass-glass construction: they are extremely resistant to hail impact, moisture and fire. It also allows energy generation on both sides (bifacial).

SolarTradex is a certified SunPower installer. Discover all the features of our SunPower Performance solar panels.

One of the main problems with conventional solar panels is that partial shading can drastically reduce the production of the entire panel. SunPower Performance panels minimise this effect thanks to their shingled cell architecture (tile-type).

How the shingled advantage works:

In a conventional panel, cells are connected in series through busbars and bypass diodes grouped in large blocks. If a single cell is shaded, the entire block drops to minimum. You can lose up to 60-70% of production with a small shadow.

In a SunPower Performance panel, the cells are arranged in overlapping strips (shingles) with much more segmented bypass. When a part of the panel is shaded:

• Only the production of the specific area affected by the shadow is lost.
• The rest of the panel continues producing at full capacity.
• The overall loss is limited to the actually shaded area, not the entire panel.

This architecture makes SunPower Performance especially recommended for rooftops with obstacles (chimneys, antennas, adjacent buildings) or with partial hourly shadows, where other brands would see their performance drop significantly.

Discover all the features on our SunPower Performance panels page.

SunPower Performance panels are covered by a 30-year warranty, one of the most solid in the solar sector. It includes three complementary coverages:

• Product: covers any manufacturing, material or workmanship defect for 30 years.
• Performance: SunPower guarantees the maintenance of performance throughout the three decades, well above the market average thanks to the panel's low annual degradation rate.
• Service: extensive coverage for panel repair and replacement, with agile process management when necessary — something that standard warranties from other brands do not include.

The data supports the reliability: it is 100 times more likely to return a conventional solar panel than a SunPower Performance panel. This translates into total peace of mind for the owner for decades.

Check the details on our SunPower solar panels page.

Yes, the initial investment in SunPower Performance panels is higher than that of a conventional panel. However, when analysing the real cost per kWh generated over the entire useful life, SunPower Performance panels usually turn out to be more profitable. These are the factors that compensate for the difference:

• Higher production per m²: they produce more energy on the same roof surface, which translates into more kWh per euro invested.
• Lower annual degradation: they maintain their performance for much longer than the market average.
• 30-year warranty (product, performance and service): the most complete in the sector, with no hidden costs in case of replacement.
• Better behaviour with partial shadows: they take advantage of rooftops with obstacles where other panels would lose a lot of production.
• Extreme durability thanks to the glass-glass construction, resistant to hail, moisture and fire.

In summary: you pay more at the beginning, but you get more energy for more years and with more peace of mind. Discover why we choose this technology on our SunPower Performance panels page.

The SunPower Performance solar panels offer extreme weather resistance, well above the usual standards of the sector. Their glass-glass construction and POE encapsulant provide them with exceptional durability against the most adverse conditions:

• Hail: certified to withstand impacts of up to 45 mm in diameter, more than double the market average.
• Aggressive environments: highly resistant to dust, sand and salt mist, ideal for coastal areas such as the Balearic Islands or the Catalan coast.

This durability is backed by the manufacturer's 30-year warranty. Check all the features on our SunPower Performance panels page.

Yes. According to Decree 192/2023, Article 6, for all photovoltaic installations requiring an engineering project (power above 10 kWn), the owner must have an active maintenance contract in place.

Complying with this regulation is crucial not only to avoid sanctions, but also to ensure the proper operation and safety of the installation throughout its useful life.

At SolarTradex we offer solar installation maintenance plans adapted to current regulations, with periodic inspections and full management of legal documentation.

The cleaning service and visual structural inspection must be carried out at least once a year, in order to guarantee the efficiency of the installation and comply with the preventive maintenance requirements demanded by the regulations.

In highly polluted environments —such as proximity to the coast, industrial areas or zones with heavy agricultural dust— the frequency can be increased to every six months to maintain the maximum performance of the panels.

We always recommend as a minimum service:

• Panel cleaning to guarantee optimal production.
• Visual inspection of the structure, with issuance of the corresponding visit report.
• Continuous monitoring of the installation: if a breakdown or performance drop is detected, we come to carry out the diagnosis at no additional cost.

This minimum service covers the legal requirements of Decree 192/2023 and ensures the validity of the maintenance contract required for installations of more than 10 kWn.

Under normal dirt conditions (dust and soil), lack of cleaning can generate an average efficiency loss of between 5% and 10% of annual production. When dirt accumulates over long periods, the losses can be much more substantial.

With a professional cleaning service, virtually all this percentage is recovered, so the cost of the service translates into an energy gain that is amortised quickly.

The price of the service is personalised and calculated based on the total power (kWp) of the installation, as well as the scope of the contract (annual visits, monitoring, incidents covered).

Each installation has unique characteristics —location, exposure to pollution, type of structure— that influence the economic proposal. Discover real examples of our industrial self-consumption service.

A maintenance contract for industrial solar panels includes specific guarantees that go beyond simple cleaning and inspection. These are the usual coverages:

• Preventive maintenance: scheduled periodic visits for cleaning, visual inspection of the structure and components, and detailed technical report.
• Continuous monitoring: 24/7 remote tracking of the installation's performance. Any anomalous drop in production triggers an automatic alert.
• Fault diagnosis at no additional cost: if monitoring detects a problem, our team travels to carry out the diagnosis included in the contract.
• Guaranteed response times: commitment to intervene within a defined timeframe based on the severity of the incident.
• Preservation of manufacturer warranties: professional documented maintenance ensures the validity of panel, inverter and structure warranties.

Specific repairs and material replacements are usually quoted separately, unless covered by the manufacturer's warranty that we manage for you. Discover all the details in our industrial self-consumption service.

The standard contractual deadline for installing solar panels is up to 90 days from the signing of the contract to the completion of the installation on your roof. This margin covers all phases of the executive project, not just the visible on-site part.

Phases included in the 90 days:

• Technical study and project: visit, sizing and preparation of the engineering project.
• Administrative processing: request for municipal licence, ICIO, notice of works and other permits required by the town council.
• Purchase and logistics of materials: order of panels, inverter, structure and components according to the approved project.
• Installation execution: the visible part of the process. On site, the installation is completed in 1 to 3 working days for most residential projects.

The 90 days is the maximum contractual margin that allows us to absorb possible external delays (responses from the town council, material manufacturing timelines, etc.). In many cases the process is completed sooner.

Note: the subsequent legalisation (registration with the electricity distributor, RITSIC, RAC) is an additional phase that depends on external bodies and is not included in this contractual deadline.

Yes, it is part of our turnkey service. We take care of all the technical and administrative paperwork so you only have to decide when we start.

Installation legalisation:

• Electrical certificate and installation report
• RITSIC registration
• Self-consumption registration with the regional authority
• Activation of the surplus energy compensation with your electricity retailer
• Paperwork with the distribution company

Study and management of applicable grants:

• Personal Income Tax deduction (up to 60% with double Energy Efficiency Certificate)
• IBI (property tax) reduction (up to 50% for 3-5 years depending on the municipal ordinance)
• ICIO (construction tax) reduction (up to 95%)
• Regional and municipal grant programmes when available

We analyse the grants available in your specific case and let you know what requirements and documentation you need to apply for them.

The main difference between both types of EV charger is the power. Domestic EV chargers (CVE) have been standardised into two values:

• Monophase: maximum power of 7.4 kW.
• Triphase: maximum power of 22 kW.

Most models on the market offer options of 7.4 kW, 22 kW, or 22 kW adjustable to 7.4 kW. This flexibility allows the charger to be adapted to the electrical installation of each home.

The choice depends on the type of electrical installation you have at home and the model of electric car:

• If you have a monophase installation: you must necessarily install a monophase charger. There is no alternative.
• If you have a triphase installation: you can install either a monophase or a triphase charger. This is where the technical assessment comes in.

Factors to consider if your installation is triphase:

• Power and charging speed: triphase chargers allow higher power, which reduces charging time. But you need to have sufficient contracted power available.
• Minimum available power: monophase chargers require between 1.4 and 2.3 kW depending on the car. Triphase chargers require between 4.1 and 6.9 kW minimum.
• Car compatibility: vehicles are also monophase or triphase depending on the model. A triphase charger powering a monophase car will see its maximum power reduced from 22 kW to 7.4 kW — you won't take full advantage of the triphase.

Still unsure which charger suits you best? Request a personalised quote and our technical team will advise you with no commitment.

The real charging power will be defined by three factors (provided the electric vehicle allows it):

• The charger's power: monophase CVE up to 7.4 kW, triphase CVE up to 22 kW.
• The contracted power with the electricity company.
• The available power, which depends on the contracted power and on what the house is already consuming. For example, with a contracted power of 5 kW and a simultaneous consumption of 3 kW, the available power for charging will be 2 kW.

The CVE can be configured manually to limit charging power, but constantly monitoring not to exceed the contracted power is very inconvenient in daily use.

For this reason we install an external meter that communicates with the CVE to self-manage the available power and use the maximum up to the set limit: this is the automatic load balancing. The charger adjusts its power in real time according to what the house is consuming, without you having to worry about anything.

Furthermore, this system is especially profitable when the charger is combined with a solar panel installation: you will recharge the car with your own solar energy without cuts or manual adjustments.

One option is to have an available power higher than the sum of the maximum powers of the CVE existing in the installation. This option requires the contracted power to be high (if the company allows it) and, therefore, a high maintenance cost.

The second option is to limit the power of each charger to ensure that the available power will not be exceeded. This option limits the charging of the vehicles and the maximum power of the CVE is never used.

The last option is to install an energy meter that communicates with the main CVE, which automatically manages the total available power between the chargers in operation. In this way, no more energy than necessary needs to be contracted (if not desired) and the CVE will operate at the maximum available power depending on the CVE in use.

This last option is especially recommended in integrated residential self-consumption solutions, where smart balancing allows the solar energy generated to be used to the maximum.

Yes, there are CVE that allow this. These chargers need to read the current consumption through an external meter (the same one used for load balancing) and adjust the charging to exclusively use the available surplus energy, respecting the minimum and maximum charging limits of the connected vehicle.

In this way, the surplus fed into the grid is minimised as much as possible. With one important limitation: if the surplus is very low, the charger will not be able to use it. For example, with 1.3 kW of surplus, the CVE will not be able to inject it into the vehicle, as it is not enough to allow the vehicle to start charging.

This operating mode enables two modalities for managing solar surplus:

• Solar surplus only: the vehicle is charged exclusively with the surplus energy from the panels.
• Grid + surplus mix: a combination of grid energy and solar surplus, with the percentage predefined by the user.

This combination is compatible with the grants and subsidies in force for self-consumption installations with electric mobility.

Domestic CVE are configured through the manufacturer's app. The initial configuration is done via Bluetooth, and the client owning the charger has full access to modify the parameters according to their needs.

Furthermore, most CVE allow internet connection to remotely manage functions such as:

• Charging scheduling by time slots.
• Manual start and stop of charging.
• Modification of the charger's maximum power.

No, an internet connection is not essential for basic operation. It is only necessary if you want to modify remote management parameters, such as:

• Start and stop charging remotely.
• Schedule charging times.
• Manage users (grant access via RFID cards, etc.).

Yes, most domestic CVE allow charging schedules to be programmed from the manufacturer's app. This feature is especially useful for taking advantage of the cheapest electricity tariffs, usually in nighttime slots.

The most complete models allow:

• Configuring personalised weekly time slots (for example, charging only from 00 h to 07 h).
• Programming specific days (weekdays yes, weekends no).
• Setting the maximum charging power during each slot.

Programming can be done locally via Bluetooth or remotely if the charger has an internet connection.

Installing an EV charger in a space of a community car park has two main options, both technically viable:

1. CVE connected directly to your home meter: if there is access from the car park to your flat, an individual derivation is installed. The wiring to reach the space can be individual or collective (community pre-installation), depending on what the residents' community decides.
2. Protection subpanel from the car park meter: a common subpanel is installed from which individual derivations run to each CVE of the car park spaces. Each user has their own consumption meter and independent bill.

The choice depends on the building's infrastructure, the number of interested neighbours and the community agreement.

These options are perfectly combinable with a collective self-consumption installation in the community: the solar surplus generated on the roof can feed the CVE in the car park, maximising savings for all neighbours.

The most practical way to bill the energy consumed when charging from the community meter is to install a MID-certified meter (Measuring Instruments Directive) in each CVE. This meter accurately records the individual consumption of each user.

From there, billing is managed through a platform administered by the community itself, which can issue charges:

• Per charging session: each user pays for what they consume in each recharge.
• At the end of the month: the total consumption is grouped and billed to the corresponding neighbour.
• Combined with a fixed fee: monthly fee + variable consumption.

This system guarantees full transparency and avoids conflicts between neighbours, as each user pays exclusively for the energy they have consumed.

Billing users is managed through a dedicated platform for this purpose. There are different platforms on the market, each with specific configurations depending on the type of intended use:

• Private use: only regular users of the charging point have access (for example, residents of a community or company employees).
• Public use: the platform is opened to any registered person, functioning as a charging point accessible to third parties.

Depending on the chosen platform, the following can be configured:

• Which users have access to the CVE (via RFID, app or PIN).
• Personalised tariffs by user or group (for example, reduced price for residents, standard price for visitors).
• Availability schedules (24/7 use or restricted to specific time slots).

Yes, there are several ways to reduce the cost of installing an EV charger at home. These are the main grants and tax advantages available:

• 15% income tax deduction (RDL 7/2026): you can deduct 15% of the cost of the charging point installation, on a maximum base of €4,000 — up to €600 in tax savings. This deduction is independent and cumulative with the deductions for photovoltaic installation or aerothermal.
• State electric mobility programmes (MOVES Plan and successors): direct grants for the installation of charging points, with amounts varying according to the type of installation and location.
• Regional and municipal programmes: in Catalonia and the Balearic Islands there are specific calls for electric mobility, as well as possible reductions in the municipal IBI (property tax) for homes with an installed charging point.

The most profitable combination is to install the charger together with solar panels, since in addition to the charger-specific grants, you can access the self-consumption grants and subsidies. Check the details of each route and see which are compatible with each other on our grants page.

At SolarTradex we handle all administrative management: you only need to sign. These are the procedures and approximate costs by territory.

Procedures in Catalonia

• Prior notice of works (municipal): declares the start of the installation to the town council.
• ICIO (Construction Tax): 4% of the PEM (Material Execution Budget, excluding VAT and fees). Most town councils apply reductions of up to 95% — we request them together with the notice.
• Municipal licence fee: approximately 1.5% of the PEM. It varies by town council; some do not charge it.
• Waste management deposit: some town councils charge it (few cases) and it is usually refundable. We handle it.
• Deferred notice of works: only in municipalities with specific regulations or listed areas. Currently required in: Barcelona, Badalona, L'Hospitalet de Llobregat, Sant Cugat del Vallès, Terrassa, Sabadell, Girona, Tarragona and Reus.
• RITSIC (Register of Industrial Safety Technical Installations of Catalonia): €34.15 paid by the client.
• RAC (Self-consumption Register): no cost. Included with the RITSIC payment.
• Opening of the work centre: no cost.

Procedures in the Balearic Islands

• Register of electricity production installations: free up to 15 kWn. Above this power: €46.76. Extensions, battery additions or modifications to existing installations: also €46.76.
• The remaining municipal procedures (licence, ICIO, notice of works) follow the same logic as in Catalonia, with amounts defined by each town council.

Energy Performance Certificate (CEE) for income tax deduction

If you want to apply the income tax deduction, you need a double CEE certification (one prior, no more than 2 years old, and another after the works).

Do we handle it? Yes. The entire administrative process (permits, registrations, applications for reductions) is managed by our team. You receive your installation up and running and fully legalised.

The timeframes depend on the type of grant, and with the new framework of the Royal Decree-Law 7/2026, the system has been simplified. The IRPF (income tax) deduction is applied in the following year's tax return (immediate effect when filing). The CAE system is the fastest incentive, as it is applied as an immediate discount on the quotation, before the works begin.

The FACTOR 2026 call in the Balearic Islands is resolved on a strict first-come, first-served basis; after the grant is awarded and the installation justified, the Government makes the payment. The municipal IBI discount depends on each town council and is usually applied from the fiscal year following the application.

Regarding the NextGeneration subsidies awarded in 2021-2022, there are still files pending resolution or payment due to administrative overload. If you have a pending NextGeneration file, we recommend consulting our specialised content on our blog for guidance on how to complete the justification and collect the subsidy.

If you are considering an energy transition in your home during 2026, it is essential to know the IRPF (income tax) deductions introduced by the Royal Decree-Law 7/2026. These incentives are designed to reward those who drastically reduce their dependence on fossil fuels.

Yes, you can deduct part of the investment in your solar installation. The amount depends on two key factors:

• The type of home: flat in a residential building (deductions from 10% to 40%) or detached house (from 20% to 60%).
• Whether the works achieve a 30% reduction in non-renewable primary energy consumption (certified with an Energy Efficiency Certificate, EEC), giving access to the higher brackets (40% for flats, 60% for detached houses).

The winning strategy

To access the maximum deductions, the most common route is to combine photovoltaic installation with aerothermal: replacing the gas boiler guarantees exceeding the 30% threshold and activating the higher deduction bracket. In addition, if you add a charger for an electric vehicle, you add a 15% independent deduction.

Joint ownership: double deduction

If the property has two owners, the deduction can be applied twice by splitting the cost of the works in two. That is, each owner can deduct up to the maximum allowed based on the type of home and action, doubling the total tax savings.

Yes, they are perfectly compatible and can be combined in the same project. In fact, taking advantage of both incentives together is the most profitable strategy under the new framework of the Royal Decree-Law 7/2026.

When a deep energy renovation is carried out — for example combining the installation of solar panels with the replacement of a gas boiler with an aerothermal system — the client can access both benefits at the same time:

• IRPF (income tax) deduction: this technical integration allows you to exceed the 30% threshold of non-renewable primary energy consumption reduction, which catapults you into the maximum tax deduction brackets, allowing you to deduct 40% (in flats in residential buildings) or 60% (in detached houses) in your IRPF.
• Direct discount through the CAE: in parallel and in addition to your income tax return, the installation of the aerothermal system generates Energy Saving Certificates (CAE) which are now enhanced by a new multiplier coefficient. The economic value of these certificates allows the installer to apply a direct discount on the initial quotation presented to you.

Check the details on our grants and subsidies for solar panels page.

Installing only solar panels usually stays within the 20% bracket. To reach the 30% consumption reduction required for the top brackets, the best routes are:

• Photovoltaic + Aerothermal: Replacing your gas boiler with an aerothermal system and adding solar panels guarantees exceeding the 30% savings threshold. It also unlocks the direct discounts from the CAE certificate system.
• If you already have electric heating: In these homes, installing solar panels alone is usually enough to achieve the 30% reduction and jump to the maximum deduction.
• Adding an EV charger: Adding a charging point to the project always provides an extra independent 15% deduction.

The fundamental technical requirement to apply these income tax deductions is having the official technical justification corresponding to each type of action, in addition to the fact that the property cannot be used for any economic activity.

This justification is provided through official certificates and by meeting minimum improvement thresholds:

1. Energy Efficiency Certificates (CEE): They are essential to justify deductions linked to the efficiency and reduction of the property's or building's consumption:

• For demand reduction: The CEE must certify that the work has reduced heating or cooling demand by at least 7%.
• For primary consumption improvement: The CEE must show that non-renewable primary energy consumption has been reduced by 30%, or that an A or B energy rating has been reached.

2. Electrical Installation Certificates (CIE): Required for electricity generation installations:

• For renewable self-consumption: The installation of photovoltaic panels is certified through the CIE. A vital requirement is that this specific deduction is not cumulative with the building rehabilitation deductions mentioned above.

3. Physical infrastructure:

• For electric mobility: The requirement is to physically install charging points for electric vehicles (EV) that are owned by the taxpayer.

The 30% reduction refers specifically to the decrease in non-renewable primary energy consumption of the property or building.

Although the regulations do not specify the exact mathematical formula, the calculation and official certification must be carried out through the Energy Efficiency Certificates (CEE). This technical certificate compares the previous and subsequent state of the property to justify access to the 40% deduction (individual homes) or 60% (entire buildings).

Note: The deduction also applies if the CEE proves that, after the works, an energy rating with an A or B label has been reached.

Technical analyses indicate that an integrated intervention, such as combining photovoltaic panels with the replacement of a gas boiler with an aerothermal system, virtually guarantees exceeding this 30% threshold.

Yes. RDL 7/2026 legally enables municipal councils to apply reductions of up to 50% on the IBI (property tax) and rebates of up to 95% on the ICIO (construction tax) for projects that integrate renewables.

Both benefits are presented as complementary incentives alongside the state income tax deductions. There is no legal restriction preventing the simultaneous enjoyment of local and state tax advantages.

Important note on incompatibilities: The only express restriction occurs internally between the income tax deductions themselves: the 20% deduction for installing renewable self-consumption cannot be combined with the building rehabilitation deductions.

Yes. Modern aerothermal systems are efficient even in very extreme temperatures. The operating limits of the equipment, in most cases, range from -7 ºC to +43 ºC.

A key principle: the smaller the temperature difference between the exterior and the interior of the home, the higher the performance. This explains why in Mediterranean climates such as Catalonia and the Balearic Islands, aerothermal energy operates at maximum efficiency during almost the entire year.

Combined with a solar panel installation, aerothermal energy is powered by its own energy source and multiplies the home's energy savings.

Savings depend on the heating and DHW (Domestic Hot Water) system you replace, but on average you can reduce the energy cost by between 30% and 70%. The key lies in the COP (Coefficient of Performance): for every 1 kWh of electricity consumed, aerothermal energy generates between 3 and 5 kWh of thermal energy.

Estimated savings depending on the system replaced:

• Compared to a natural gas boiler: 30-50% savings on your energy bill.
• Compared to diesel or propane: 40-60% savings.
• Compared to conventional electric heating: 50-70% savings.

These savings can be drastically multiplied if aerothermal energy is combined with a residential self-consumption solution: by powering it with the energy generated by your own solar panels, the operating cost can approach zero for many months of the year.

Yes, aerothermal energy is considered a renewable energy source, as it takes advantage of the thermal energy in the air, an inexhaustible, free and environmentally friendly source. It only uses a small part of electricity consumption for its operation.

Being officially renewable, aerothermal energy is eligible for grants and subsidies for energy renovation and ecological transition.

No. Aerothermal is one of the climate systems that requires the least maintenance, especially compared to gas or diesel boilers. As there is no combustion, there are no chimneys, no fuel tanks, and no parts subject to high wear.

Basic annual maintenance:

• Annual professional inspection: check of the refrigerant circuit, pressures, sensors and general state of the equipment.
• Cleaning of the outdoor unit: removing leaves, dust or dirt accumulated on the heat exchanger (the user can do this themselves).
• Indoor filter: cleaning or replacement every 6-12 months depending on use.

With this minimal maintenance, the useful life of an aerothermal system ranges between 15 and 20 years, with very few incidents throughout its life.

The installation adapts to both a newly built house and a renovation, replacing the existing boiler. As a diffusion system, previously installed elements can be used:

• Radiators (conventional or low-temperature).
• Underfloor heating, the most efficient option due to its low thermal gap.

The integration is very simple and allows a considerable improvement in the home's energy efficiency.

The total installation time can vary depending on the dimensions of the home and the equipment used. In most cases, installations are quite quick and are completed within 5 to 7 days. For very complex installations, it can take up to 10 days.

Factors that influence the duration:

• Replacement of existing boiler: if there is already a distribution installation (radiators, underfloor heating), the process is faster within the usual range.
• Installation in new construction or without a previous system: it can lengthen the execution as the entire emission network and DHW tank must be installed.
• Location of the outdoor unit: if minor masonry work or specific piping is required, additional time is added.

The installation does not cause damage or harm to the building: it is a clean process, with minimal work and perfectly compatible with inhabited homes.

Yes. Aerothermal energy is one of the technologies best positioned to access grants and tax advantages, precisely because of its official recognition as renewable energy and its high energy-saving potential. The main available routes are:

• Income tax deduction (RDL 7/2026): up to 40% in flats and 60% in single-family homes if the 30% reduction in non-renewable primary energy consumption is exceeded — something that aerothermal energy achieves practically by default when replacing a gas or diesel boiler.
• Energy Saving Certificates (CAE): direct discount applied to the project invoice by the installer, thanks to the certified energy saving of the system change.
• Municipal reductions: up to 50% on the IBI (property tax) and up to 95% on the ICIO (construction tax) in many municipalities of Catalonia and the Balearic Islands.
• Regional programmes: in the Balearic Islands, for example, the FACTOR 2026 programme includes specific grants for energy renovation with heat pumps.

Check the details of each route and see which are compatible with each other on our grants and subsidies page. Our team handles all the necessary documentation so that you can take full advantage of the benefits.