Políticas y Legislación sobre Eficiencia Energética

European building energy efficiency regulation has followed an escalating trajectory of ambition through 4 legislative stages. The first EPBD (Directive 2002/91/EC) introduced the mandatory energy performance certificate and minimum energy performance requirements, but left the setting of thresholds to each member state, creating disparities: the maximum permitted wall transmittance ranged from 0.20 W/m²·K in Sweden to 0.82 W/m²·K in Portugal. The 2010 EPBD recast (Directive 2010/31/EU) defined the concept of the nearly zero energy building (NZEB) and established that all new buildings must be NZEB from December 31, 2020 (2018 for public buildings). The Energy Efficiency Directive (2012/27/EU, revised in 2023) set the target of reducing primary energy consumption by 11.7% by 2030 relative to the 2020 reference scenario, with annual savings obligations of 1.49% of final energy consumption for each member state. These three directives generated estimated cumulative savings of 1,900 TWh of final energy in the European building sector between 2005 and 2022 (European Commission, 2023).

The 2024 EPBD recast (Directive 2024/1275) represents a qualitative leap. It defines the concept of the Zero Emission Building (ZEB): very low energy demand, fully covered by renewables (on-site, nearby, or from the grid with guarantee of origin), and zero direct emissions from fossil fuels. The deadlines: new public buildings must be ZEB from January 1, 2028, all new buildings from January 1, 2030. For existing stock, non-residential buildings must reach at least class E by 2030 and class D by 2033; residential buildings, class E by 2030 and class D by 2033 (with flexibility to exempt up to 22% of the stock). The ban on standalone fossil fuel boilers in new buildings takes immediate effect, and subsidies for fossil boilers are eliminated from 2025. The least efficient 16% of non-residential buildings must be retrofitted by 2030, and 26% by 2033. This directive affects 220 million buildings in the EU, of which 75% are energy-inefficient (BPIE, 2023).

The Spanish Technical Building Code (CTE), approved in 2006 and substantially updated in 2019, transposes European directives through the Basic Document on Energy Savings (DB HE), which establishes 5 basic requirements: HE0 (limitation of energy consumption), HE1 (limitation of energy demand), HE2 (thermal installations — deferred to the RITE), HE3 (lighting), HE4 (minimum renewable energy contribution for DHW), and HE5 (minimum electricity generation — for non-residential use buildings). The 2019 update reduced thermal transmittance limits by 30-50% relative to the 2006 version: facade wall maximum U-values went from 0.82 W/m²·K (zone A) - 0.57 W/m²·K (zone E) to 0.56 W/m²·K (zone α) - 0.27 W/m²·K (zone E). Non-renewable primary energy consumption was capped at 32 kWh/m²·year (zone α) - 80 kWh/m²·year (zone E) for residential use, values that place Spain in the medium-high range of European stringency.

The next CTE update, planned for 2025-2026, must transpose the 2024 EPBD and introduce the ZEB standard. Anticipated changes include: elimination of gas boilers in new construction, a requirement for solar photovoltaic installation in all new buildings (not just non-residential), an additional 20-30% reduction in transmittance limits (approaching Passivhaus values in zones D and E), and the incorporation of life-cycle carbon indicators (kgCO₂e/m²·year). The RITE (Regulation on Thermal Installations in Buildings, updated in 2021) complements the CTE by regulating minimum generator performance (boilers with η ≥ 92% on GCV, heat pumps with SCOP ≥ 2.5 in climate zone D), indoor air quality (airflow rates of 8-12.5 liters/s·person by IDA category), and periodic inspections of thermal installations (mandatory every 4 years for capacities > 70 kW, every 5 years for > 12 kW). Spain has 25.7 million homes, of which 81% hold energy ratings of E, F, or G (Ministry for the Ecological Transition, 2023), implying the need to retrofit 15-20 million homes over the next two decades.

Globally, 85 countries have mandatory building energy efficiency codes covering 73% of the world's new construction floor area, according to the IEA (Global Status Report, 2023). The most stringent include Sweden (heating demand ≤ 55 kWh/m²·year for multi-family buildings, regardless of climate zone), Denmark (primary energy consumption ≤ 20 kWh/m²·year for 2020-class buildings), and British Columbia's (Canada) BC Energy Step Code, with 5 progressive levels up to Net Zero Ready by 2032. The IFC/World Bank's EDGE program (Excellence in Design for Greater Efficiencies) has certified more than 7,500 buildings in 170+ developing countries, with a minimum threshold of 20% savings in energy, water, and embodied carbon versus a local baseline. China updated its GB 55015-2021 requiring a 72% reduction in heating demand relative to the 1986 standard, and has built more than 8 billion m² of efficient buildings since 2005. India applies the ECBC (Energy Conservation Building Code) as mandatory for commercial buildings > 500 m² since 2017, with demonstrated savings of 25-50% in energy consumption.

Economic instruments complement technical regulation. Direct subsidies for energy retrofit in the EU exceeded 40 billion EUR in the 2021-2026 period (NextGenerationEU funds + national programs). In Spain, the Recovery Plan allocates 6.82 billion EUR to energy retrofit of buildings and homes, with grants of 6,300-18,800 EUR/home (up to 80% of cost for vulnerable households) managed by the autonomous communities. Tax deductions for energy retrofit in the Spanish personal income tax (in effect 2021-2025) allow deduction of 20-60% of investment in envelope improvements, installations, and certification, with maximum bases of 5,000-15,000 EUR. Green mortgages offer interest rates 0.1-0.3% below the standard rate for properties with A or B energy ratings, incentivizing demand for efficient buildings. Carbon taxes, such as the European ETS (which reached 100 EUR/tCO₂ in 2023), and its extension to the building sector (ETS2, planned for 2027, with an estimated price of 40-60 EUR/tCO₂), will make fossil fuel consumption for heating progressively more expensive.

The gap between legislative ambition and actual implementation is substantial. The deep energy retrofit rate in the EU is 0.2% of the building stock per year (BPIE, 2023), compared to the 3% needed to meet 2050 targets. At this pace, retrofitting the existing stock would take 500 years, not 25. In Spain, only 34,000 homes received Recovery Plan grants in 2022 (the first year of execution), versus the 500,000 homes/year needed to comply with the 2024 EPBD. The causes of this gap include: administrative complexity (a grant application requires an average of 14 documents and 4-8 months of processing), lack of skilled labor (120,000 additional workers needed in Spain to reach the required retrofit pace, according to CCOO Construction, 2023), financing difficulties for homeowner associations (80% of Spanish homes are in co-ownership regimes, where a retrofit decision requires a qualified majority of 3/5 of owners), and the absence of a real obligation to retrofit (the 2024 EPBD includes penalties but leaves their definition to member states).

The legislation also presents internal tensions. The requirement for ZEB in new construction from 2030 could discourage retrofit of the existing stock if developers concentrate investment on demolishing and rebuilding (with an unfavorable carbon balance: demolishing and rebuilding emits 3-5 times more CO₂ than retrofitting to the same efficiency level, according to a UCL study for Historic England, 2019). The mandatory installation of photovoltaics on all new buildings ignores orientation, shading, and heritage protection constraints that affect 15-25% of urban plots. The ban on gas boilers faces resistance in areas with amortized gas infrastructure (40% of Spanish households use natural gas for heating) and in rural areas lacking adequate three-phase electricity networks for heat pumps over 6 kW. Energy efficiency policies and legislation have advanced at a commendable pace — the EU has the most ambitious regulatory framework in the world in this field — but the distance between the letter of the law and actual retrofitted homes remains the sector's principal challenge.