How many solar panels do I need?

Below, we explain and solve the main doubts you usually have about the installation of solar panels for self-consumption.


Is it legal to install solar panels for self-consumption?

YES, of course. It is legal in any case and situation. 

Solar panels get integrated perfectly on houses roofs. The solar energy production does not create any inconveniences, and moreover, besides small urbanistic details most city councils have fast procedures and help lines to make it easier for this technology.


Do I have to pay taxes to install solar panels?

NO. Since October 2018, with the approval of Real Decreto 15/2018, the taxes related to energy generation for self-consumption got anuled.


What happens with the solar energy I cannot use in the moment I am generating it?

Since March 2020 (and before with certain companies) the surplus solar energy (the one solar panels generate and you don't use instantly at your home) can be compensated economically in the electrical bill.

This is what is called Economical Compensation in Bill. You recieve it the month after, with a lowe kWh price than the buying one (around 0,05€/kWh). Here you can see an example, where the surplpus produced energy by the solar panels gets compensated in the same bill:

plaques solars factura llum


Do I have to ask for permison to the electrical company to put solar panels?

  1. NO. If the solar panels installation power is inferior to 15kW you don't have to ask for any permit to the electrical company to be able to send the surplus energy to the net.
  2. YES. If the solar panels installation power is superior to 15kW and you want to compensate the surplus energy.
  3. NO. If the solar panels installation power is superior to 15kW and you DON'T want to compensate the surplus energy.


Do I have to install another meter if I install solar panels?

NO. With previous legislation it was but nowadays not anymore as long as you don't want to do shared self-consumption.


How many solar panels do I need?

Watts At Home does not work with "solar kits". Every client is unique, and needs a tailored solution. Sometimes, with good management of the consumption you can reduce the number of needed solar panels.

We ALWAYS offer a free initial quotation for your home, so you know how many panels you need. In an average hom, with 8 to 14 solar panels we can cover most of the yearly consumtpion.

Click here, and ask for a quotation! 


If the electrical network fails, what happens?

In most cases, the self-consumption solar systems work in parallel to the net, so if the net fails, the solar panels installation stops. Howeverot, we have solar systemas that can work as a support for the net, or the net can work as their support. Also some battery producers are starting to offer products that can work even when the net fails

Click here, and ask for more information about batteries and solar panels! 


How much can I save in my electrical bill with solar panels?

To know how much you can save, we have to do a personalized quotation to know the best solution for the situation, because depeding on the consumption and the home appliances schedule, we will recomend the number of panels. It is preferable not to cover consumption peaks and be able to amortize the installation sooner, and this way give away the least surplus energy possible to the company. It is also important to know that the dimensioning is done based (one part of it) on the average radiation values on your location, so consequently, even though it is pretty accurate, it changes from year to year. With an average installation you can save around 40 to 60% of the year energy, but with batteries we can get to 80 or 90%.

Click here, if you want a free quotation! 


Can I sell the electricity generated with solar panels that I have not consumed?

YES, even though this implies to make a selling contract with the electrical company, and start a new IAE (Economical Activity Tax). It is easier and similar economically to compensate the surplus energy in the same bill.


Do I have to keep paying the bill if I have solar panels?

Yes but you will pay much less!! Solar panels work during sun hours, and if you don't have batteries, you will need the net whenever the sun is not out. Besides, you will have to keep paying to hire the net power.

Here you can see an image of an installation where they save around a 70% with solar panels:

plaques solars estalvi a casa

  1. The red area is the consumed energy when solar panels are not producing energy.
  2. The blue area is the solar panels produced energy and consumed at the same time: SELF-CONSUMPTION
  3. The green area is the solar panels produced energy and sent to the net. Solar Energy Surplus


What is the solar installation warranty? And the materials one?

Photovoltaic solar panels have a higher warranty than 10 years, and 25 years of minimum production. Batteries have a higher warranty than 5 years and around 6000 charge and discharge cicles (one cicle per day is 16 years). In our case, we try to install solar panels with 25 years warranty (product one) and produced in Europe. The inverters that we install give (without any extra cost) 12 years warranty, 7 more than most brands.

What maintenance costs are there?

Solar panels maintenance costs are very low in this type of installations. We could say that it is practically zero. It is recomended that once a year there is some preventive maintenance, like solar panels cleaning, checking the structure, conections state and cable conditions. We offer a maintenance at a very reduced cost, with online monitoring, and reports with the details of how your installation is working.

Click here, if you want a free quotation! 


Do I have to legalize the solar panels installation?

YES. First of all, we recomend you to ask for the construction permit to you city council. Most towns have some reductions for this type of installations. Afterwards, once the installation is finished, we give you the bulletins and legislative inscriptions to Generalitat de Catalunya, including forms, and taxes. It is a brief and simple process for any installation under 100kW, and even more so when under 15kW.

Click here, and we will inform you about the necessary steps to legalize solar panels once installed! 


Are there other lines of help to install solar panels? Do Watts At Home help with the process?

YES, there are some city councils or corporations that offer lines of help, or discounts to taxes such as IBI (tax for houses and similar properties). Our technical team can check it out, and obviously, all processes are included within the initial price.

Check here, and ask if at you Postal Code there is an IBI discount if you install solar panels! 

Following we attatch a list with the towns where we know the existing lines of help:

  • Aiguaviva
  • Artés
  • Avinyó
  • Badalona
  • Barcelona
  • Balenyà
  • Begur
  • Borrassà
  • Cabrils
  • Calaf
  • Calafell
  • Caldes de Malavella
  • Cassà de la Selva
  • Castelldefels
  • Cerdanyola del vallès
  • El Prat de Llobregat
  • Figueres
  • Folgueroles
  • Fonteta
  • Girona
  • Granollers
  • Hostalric
  • L'Estartit
  • Llagostera
  • Lleida
  • Manlleu
  • Manresa
  • Navàs
  • Navata
  • Olost
  • Olot
  • Palafrugell
  • Palma de Mallorca
  • Pallejà
  • Perafita
  • Peratallada
  • Polinyà
  • Rajadell
  • Rubí
  • Torroella de Montgrí
  • Sabadell
  • Sallen
  • Sant Boi del Llobregat
  • Sant Cugat del Vallès
  • Sant Fost de Campsentelles
  • Sant Fruitós de Bages
  • Sant Just Desvern
  • Sant Pere de Ribes
  • Sant Pere de Torelló
  • Sant Quirze de Besora
  • Sant Vicens de Castellet
  • Santa Coloma de Gramenet
  • Santa Perpètua de la mogoda
  • Sant Vicenç de Montalt
  • Santpedor
  • Sora
  • Tàrrega
  • Terrassa
  • Vacarisses
  • Valldoreix
  • Vidreres
  • Viladecans
  • Vilanova i la Geltrú
  • Vulpellac

In some cases, the help can cover 50% of the tax!

Click here, and we will inform you about you town lines of help! 


Can I produce energy at my roof and share it with my neighbors?

YES, It is called shared self-consumption. It allows energy to be created at a location and other consumers (they have to be low tension, and within 500 square m) to use it with an internal or external net 



Watts at Home


Watts at Home


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