Energy efficiency and the value of residential assets in Spain

• IESE, Tinsa by Accumin, and Accumin Intelligence conduct the first study to statistically demonstrate the impact of energy efficiency on the value of residential properties in Spain, isolating it from other construction variables.
• The added value of an energy rating improvement averages 1.3%. The increase is most significant in transitions between higher and more efficient ratings, especially improvements from C to B (3.3%).
• The green premium is consistently relevant across all regions, price ranges, typologies, and ages.
• This report highlights how energy efficiency not only improves environmental performance but is also a key factor in increasing the economic value of homes in an environment of growing climate awareness and regulation, positioning itself as a strategic factor for the future of the real estate sector.

Climate Impact of the Real Estate Sector in Spain

The real estate sector is responsible for 40% of global greenhouse gas emissions (UNEP FI 2022) and, consequently, plays an essential role in reducing carbon emissions.

In Spain, the residential stock consists of more than 26 million homes, 95% of which were built between 1960 and 2009, before energy efficiency requirements began to be applied. This age means that nearly 95% of the Spanish residential stock is energy inefficient, with a high concentration in the E category.

Representative Database

This study analyzes the specific impact that energy efficiency improvements have on the value of residential properties in Spain. To do so, it uses a database of 243,414 residential properties distributed throughout Spain between 2012 and 2024. The records collected for these homes cover three key dimensions: energy efficiency certificates (provided by Accumin Intelligence), the homes' structural and functional characteristics (year of construction, construction quality, and overall state of repair), and market valuation based on professional appraisals (both provided by Tinsa by Accumin).

Rigorous Methodology

Using a regression discontinuity identification methodology, the analysis leverages locally exogenous variations in energy efficiency ratings around the thresholds that separate each letter on the scale. This methodology makes it possible to isolate the specific impact of the improvement in energy ratings, focusing exclusively on the effect of the certificate on the value of the homes and eliminating external influences. Furthermore, to ensure temporal consistency and validity of the observations, the interval between the appraisal and the energy efficiency assessment is always less than 12 months. This approach ensures that the relationship between energy efficiency and market value is representative of current reality and not biased by time factors. All of this guarantees robust and accurate results that specifically reflect the economic value that greater energy efficiency brings to the real estate market.

Analysis of Results

The analysis reveals that the added value of a one-letter improvement in the energy rating is, on average, 1.3%. Some transitions, such as from category "C" to "B," have a greater impact, reaching 3.3%. This suggests that buyers value energy efficiency improvements more when they represent a significant change in sustainability and energy-saving standards. Even so, the "Green Premium" is present in all transitions between energy efficiency levels, making it a widespread phenomenon in the market.

Furthermore, the "Green Premium" is not an isolated phenomenon or exclusive to one market segment, but is consistently evident across all regions, price ranges, ages, and housing types.

The results thus confirm the importance of energy efficiency as a cross-cutting attribute in real estate valuation.

The trend observed over the last decade suggests that energy efficiency will continue to play a fundamental role in property values, driven by both market demand and public policies geared toward sustainability. The evidence presented underscores the need to continue incentivizing energy efficiency in the real estate sector, not only as a tool for reducing emissions, but also as a key strategic factor for increasing the economic value of properties.