More than 36,000 Spanish homes will have solar panels installed in 2025, Spanish Photovoltaic Union (UNEF). But installing solar panels at home doesn’t always save as much as you might expect. “It depends,” he replied. David Carracedo, Civil Engineer, Canals and PortsSpecialist in hydrology and energy. It depends on how much you use, when you use it and in your home.
If you use electricity produced by photovoltaic systems, solar panels save electricity; But the installation may be unnecessary if you use most of your electricity at other times, for example, if you have a second home that you visit on weekends. The environment plays an important role, because the shadow of buildings or trees can reduce performance; In a villa, installing solar panels can be easier than in a nearby community home.
A shade can be calculated before purchasing the plate. Genbeta has already published an article on the ShadowCalculator website, which simulates the shadow of a building or an object where solar panels will be installed on an interactive map.
The most common mistake, according to Carracedo, is installing panels without first studying what hours of electricity are used.
“The best installation is not the biggest one or the one that takes up the whole roof, but the one that is properly designed for the actual costs and family schedule”Carracedo analysis. If you could make just one improvement to your home over the next two decades, he adds, you’d focus your efforts on insulation and energy improvements to the building envelope. “The cheapest and most sustainable energy is the one we don’t need to use”.
With adequate insulation, the amount of electricity used to heat or air condition the home is reduced, representing savings that do not depend on solar energy. This decline has continued for decades.
The next change that he would introduce into a home, he confirmed, would be consumption A more efficient air conditioning systemSuch as heat pumps, with an installation size that adapts to the specific needs of the household. Regarding measures to save water consumption, the engineer believes that simple options, such as fixing leaks and replacing taps with more efficient ones and cisterns with dual flush models, are better options than more sophisticated reuse systems.
In the long term, technology will change our relationship with energy and water. In ten or twenty years, Carracedo predicts, it will be possible to know in almost real time how much electricity and water is used. The advent of the smart home will mean that appliances will activate when solar power is available: “Homes will recharge water heaters, washing machines, dishwashers or electric cars if solar power is available.”. In neighboring communities, shared self-consumption will allow owners to take advantage of the energy produced by panels on the same roof.
To achieve energy self-sufficiencyAdequate solar panels and batteries are required to cover nights, winters and low production days. Furthermore, the difference will be made with better insulation and a design adapted to the climate with an efficient ventilation system, capable of maintaining a comfortable temperature with much less energy. “What may seem like a technical or sustainable house to us today, will probably be seen as a completely normal house in twenty years”He prophesies.
What can be done now and when it pays off
But there are some simple tips that can be implemented right away. Many washing machines and dishwashers delay the start of the wash cycle at a certain time. In this way, the user can synchronize the machine with the moments of lowest power consumption. Depending on the model, the delay is programmed in increments of hours or hours. The difference with what Carracedo describes is that here you choose the time and the machine doesn’t know if the sun is there at that moment.
Without solar panels, The working afternoon falls during the peak periodincluding the most expensive tolls. According to CNMC Circular 3/2020, in force for peninsular, Balearic Islands and Canary Islands at 2.0TD toll (low voltage supply compressed to 15 kW), peak hours with the most expensive toll are from 10:00 a.m. to 2:00 a.m. and a flat period from 6:00 pm to 10:00 pm weekdays 8:00 am to 10:00 pm, 2:00 pm to 6:00 pm and 10:00 pm to 12:00 pm.
And it’s off-peak from 00:00 to 08:00, as well as on weekends and national holidays. Users benefit from using the valley strip without solar panels for additional power supply. At noon on Monday, a user without solar panels is in the peak strip, which has the most expensive toll.
How much will be saved with the surplus depends on the type of contract that is made so that electricity that is produced, but not used, is offset by electricity purchased from the grid, and the length of the settlement period.
In the case of simplified compensation established by Royal Decree 244/2019, which limits it to installations with power up to 100 kW, the electricity not used in a month’s bill is compensated with the amount of electricity purchased from the network, but never more than that amount. With reference marketing companies, what is paid to producers counts Average hourly market price less deviation cost.
In Spanish residential self-consumption, in 2025, 36,330 homes and 229 MW were added, 17% less than the 275 MW of electricity added in 2024. UNEF link Part of recession at the end or uncertainty of incentives. Among the reasons cited is the continued decline in surplus prices at the free rate.
Engineers save by using electricity that is generated at home.
What is required to start the washing machine itself?
How is it achieved? Matter version 1.4, released in November 2024, includes device power management: it allows power-consuming devices to adjust their startup times based on consumption forecasts. Additionally, it extends support for solar inverters, batteries and heat pumps. Just because the standard allows it doesn’t mean your washing machine covers it..
Different ways are being developed to manage what happens at home. The Home Assistant energy dashboard integrates data from the electrical grid, solar panels and batteries as well as individual devices. Home Connect promises to turn on appliances when electricity is cheap or when panels are generated, with a solar system or flexible tariff and HomeWizard’s P1 meter. It is not clear where it can be used, so it is recommended to confirm that it works with local meters.
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