Article
How to renovate a home to boost energy savings
Reducing energy consumption, cutting CO₂ emissions and improving occupants’ thermal comfort are just some of the main reasons for undertaking an energy-efficient home renovation. Whatever your motivation for carrying out the upgrade, the key is choosing the right measures to achieve the best results with the lowest possible investment.
When people think about energy-efficient renovation, the first thing that usually comes to mind is replacing windows. While this is an effective measure, it also requires a significant investment, which is why it is often postponed until a full refurbishment is carried out. However, there are more affordable solutions that can deliver similar energy results, such as improving the building envelope. For example, injecting mineral wool into air cavities in façades, roofs or suspended ceilings can achieve results comparable to replacing windows, but at around a third of the cost.
For those looking to go a step further in renovation, aerothermal energy becomes a key ally, although a lack of public awareness about this technology can sometimes lead to it being dismissed as an option. There are several types of heat pumps that adapt to different homes and needs:
- For water-based heating systems (radiators or underfloor heating), aerothermal solutions are recommended.
- If a home does not have heating but requires both cooling and heating, suitable solutions are also available.
- For homes that only require hot water, heat pump water heaters are the most efficient option.
There is no one-size-fits-all rule for every home. Recommendations depend on the year of construction, the condition of the property, its characteristics and the available budget.
What is energy-efficient home renovation and why does it matter?
Energy-efficient home renovation involves upgrading existing buildings to reduce energy consumption and CO₂ emissions, while improving habitability and occupants’ thermal comfort. Beyond individual efficiency, these actions contribute to national and European decarbonisation targets, as the residential sector accounts for around 18% of final energy consumption in Spain.
This transformation also helps improve a property’s energy rating, making it easier to meet the legal requirements expected by 2030 and increasing its market value.
The main objective is to maximise energy savings with the lowest possible investment, through a strategic combination of measures:
According to recent studies, a well-planned comprehensive renovation can reduce energy consumption by between 30% and 60%, with the investment typically paying for itself in around a decade.
What’s more, energy-efficient renovation delivers further positive impacts, such as improved indoor air quality, reduced damp and noise, and job creation in the construction and energy-efficiency sectors.
Ultimately, it is not just about financial savings, but about adapting homes to a sustainable future, increasing their value and comfort and contributing to the country’s climate and social goals.
Measures and advice for energy-efficient home renovation
Depending on the type of home and the heating or cooling system, there are specific actions that can maximise energy savings and improve comfort:
Measures and advice for energy renovation based on the type of home
Detached house with an oil-fired boiler
Very common in cold areas, especially rural parts of Galicia and Castile and León.
Improving roof insulation and adding solar photovoltaic energy can achieve savings of up to 80%, allowing most heating and hot water consumption to be covered at no cost.
Replacing the oil-fired boiler with aerothermal heating can deliver average savings of 50%, even when using older radiators.
This solution benefits from tax deductions and energy-saving certificates, offering up to €10,000 in savings on the investment.
Detached house with an old air-conditioning unit
Common along the Mediterranean coast and in southern Spain.
When combined with insulation improvements and solar panels, total savings can reach 70%-80%.
Replacing an old air-conditioning unit with a modern inverter system with heat pump technology enables savings of 20% to 40%.
Installing a heat-pump water heater is also recommended.
Flat with an old air-conditioning unit
Typical in Andalusia, Murcia and other warm regions.
Switching to a modern air-conditioning unit offers savings of 20% to 40%, rising by a further 30% if ducting is already in place and zoning is implemented.
Installing solar panels may depend on the homeowners’ association, although it is often possible to join a solar community at no additional cost.
Flat with a boiler and radiators
Common in densely populated areas with cold climates (northern and central Spain).
Improving façade insulation can deliver savings of around 30%.
Replacing the boiler with aerothermal heating provides an additional 30%-50% in savings, depending on the radiator type.
Installing solar panels on the roof of the building requires approval from the homeowners’ association. The Horizontal Property Act is currently under review to make this installation easier with the support of only one-third of residents.
General recommendations
- Measures are cumulative and can be carried out in stages without difficulty
- It is important to plan all actions from the outset, even if they are implemented later, so that one does not limit another
- The sooner measures are implemented, the sooner the resulting savings can be enjoyed
- Iberdrola España offers interest-free financing options to help facilitate these investments
Careful planning and the right combination of measures make it possible to achieve maximum energy and financial savings, while improving comfort and contributing to household sustainability. These actions not only reduce energy bills but also prepare homes to meet the efficiency targets of the near future.
Grants and Iberdrola España’s commitment to energy efficiency in homes
At Iberdrola España, we support households at every step of the energy-efficient renovation process. We identify the most suitable measures for each home, provide a free estimate of potential savings and manage available grants and tax deductions.
Our approach goes beyond financial savings. We also promote improved thermal comfort, better habitability and genuine added value for the property.
We offer a comprehensive turnkey service that allows customers to invest with confidence: personalised advice, installation of improvements, management of public subsidies and interest-free financing.
Through this commitment, Iberdrola España is positioning itself as a strategic partner in the energy transition of Spanish homes, helping each property become more efficient, more comfortable and better prepared for the future.
The key to energy efficiency lies in planning all actions from the outset, combining measures cumulatively and implementing each intervention at the right time. In this way, every euro invested translates into real savings and tangible comfort, while helping Spanish homes become more efficient and sustainable both now and in the years ahead. Aerothermal solutions are transforming the way we enjoy our homes.
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