Energy requalification: a complete guide to the energy efficiency of buildings

Energy retrofitting is today one of the most important levers to reduce consumption, cut emissions, and improve the comfort of buildings. It concerns both private homes and businesses and public structures throughout Europe. Interventions such as thermal insulation, efficient systems, and renewable sources transform obsolete buildings into modern, sustainable, and valuable spaces. In a European context aiming for climate neutrality by 2050, retrofitting represents an opportunity and necessity to build a greener and more competitive future.

What is energy retrofitting?

Energy retrofitting is the set of interventions that improve the efficiency of a building, leading to lower consumption, reduced environmental impact, and living or working in more comfortable spaces.

It is not just an aesthetic improvement but a transformation that acts on three fronts:

• Enclosure: insulation of walls, roofs, and floors, replacement of fixtures.

• Systems: heating, cooling, and hot water production with efficient solutions.

• Renewables: photovoltaic, solar thermal, and storage systems.

The goal is simple: to transform an energy-intensive building into a modern and sustainable space.

Typical interventions

Among the most common solutions are:

• Thermal insulation and coating.

• Windows with double or triple glazing.

• Heat pumps or condensing boilers.

• Photovoltaic panels with storage batteries.

• LED lighting.

• Controlled mechanical ventilation.

• Building automation systems.

If combined, these interventions can cut consumption by 40–50%.

Not just a simple renovation

Be careful not to confuse retrofitting with renovation. The two can go together, but the difference in objectives remains clear:

• Building renovation focuses on aesthetic or structural aspects (facade, interior spaces, extensions).

• Energy retrofitting aims to improve performance, reduce costs, and increase the property's value.

A tailored path

Every building is unique. A detached house in a cold area does not have the same needs as a condominium in the city or an industrial warehouse.

That’s why retrofitting always begins with an energy diagnosis.
This study identifies critical issues and defines the most suitable intervention plan, considering time, costs, and returns.

Why energy retrofitting is essential today

Retrofitting is not just a matter of comfort: it is a strategic lever for families, businesses, and communities.

Energy savings and lighter bills

Intervening on the building means consuming less energy for heating, cooling, and lighting.
Well-designed interventions can reduce consumption by up to 50%.

A direct benefit for families, who see monthly expenses decrease, and for businesses, which can free up resources to reinvest.

Comfort and quality of life

An efficient building is also a more pleasant environment.

• No more drafts or temperature fluctuations.

• Better acoustic insulation.

• Superior air quality thanks to ventilation systems.

These are aspects that impact the daily well-being and health of those living or working in the spaces.

Economic value and competitiveness

Renovated properties have a higher market value.
For companies, operating in modern and sustainable buildings means being more attractive to customers, partners, and investors.

An energy-efficient office, for example, is a business card that communicates innovation and responsibility.

Environmental benefits

Last but not least: the positive impact on the planet.

Reducing consumption means cutting CO₂ emissions and contributing to European climate goals.
At a time when sustainability is at the center of public policies, energy retrofitting becomes an integral part of the ecological transition.

Areas of application for energy retrofitting

Energy retrofitting is a cross-cutting strategy.
It concerns not only private houses but also businesses, public buildings, and even entire neighborhoods.

Residential buildings

Homes represent the heart of energy demand. Here interventions translate into immediate benefits for families.

• Single-family homes and villas: thermal insulation, high-performance fixtures, photovoltaic systems with batteries. A heat pump is often integrated for heating and hot water.

• Condominiums: more complex interventions but with a greater impact. Insulating an entire building or replacing the centralized system generates significant savings for all residents.

In both cases, lighter bills, more comfortable environments, and a higher property value are achieved.

Businesses and production sites

The industrial and tertiary sectors consume large amounts of energy. Retrofitting means reducing costs and increasing competitiveness.

• Production plants: large photovoltaic systems, storage systems, heat recovery from processes.

• Offices and management centers: LED lighting, efficient air conditioning, building automation systems.

Besides economic savings, companies gain a reputational advantage: being sustainable is now a differentiating element in the market.

Public buildings

Schools, hospitals, and municipal offices are often dated buildings with high consumption. Taking action here has a dual effect:

• Cutting current expenses for administrations.

• A concrete example for citizens and businesses.

A more efficient hospital is also more reliable in case of blackouts. A renovated school provides healthier environments for students and teachers.

Energy communities

Retrofitting is also the starting point for local energy communities.
Groups of citizens, businesses, and public administrations can share renewable energy produced and consumed on-site.

It is a model that combines sustainability, inclusion, and collective savings, contributing to more resilient cities.

Main retrofitting and energy saving interventions

Energy retrofitting materializes through a series of targeted interventions.
Some concern the envelope, others the systems or digital technologies. Together they build a more efficient system.

Thermal insulation

Thermal coating, roof insulation, or floor insulating reduces heat loss.
Less loss means less use of systems and lower bills.

Among the most used materials are:

• Rock wool.

• Wood fiber.

• Aerogel and innovative materials.

The choice depends on the climate, the building, and the budget.

High-performance fixtures

Modern windows and doors eliminate drafts and improve acoustic insulation.
Low-emissivity double or triple glazing, combined with insulating frames, are now the standard.

Heating and cooling systems

The most common solutions are:

• Heat pumps: use energy from air, water, or ground for heating and cooling.

• Condensing boilers: more efficient than traditional models.

• Hybrid systems: combine boilers and heat pumps, optimizing consumption based on the weather.

For large structures, systems for recovering heat from production processes or ventilation are added.

Renewable energy

Integrating renewable sources is essential.

• Photovoltaics: produces clean electricity.

• Storage systems: allow using energy at night or on cloudy days.

• Solar thermal: useful for sanitary hot water.

The combination of these technologies leads buildings towards self-sufficiency.

Complementary technologies

Other less invasive but very effective interventions include:

• LED lighting.

• Controlled mechanical ventilation (CMV).

• Building automation for smart consumption management.
  
  
  

The integrated approach

The maximum benefits are obtained by combining multiple interventions.
An insulated building, with high-performance fixtures, photovoltaic systems, and a heat pump, becomes resilient to energy price increases and significantly reduces emissions.

The European framework for energy retrofitting

In Europe, buildings are responsible for 40% of energy consumption and 36% of greenhouse gas emissions. Numbers that show how urgent it is to intervene.

European Green Deal

With the Green Deal, the EU has set two key objectives:

• Cut emissions by 55% by 2030.

• Achieve climate neutrality by 2050.

Energy retrofitting is one of the pillars to achieve this.

The Renovation Wave

To accelerate change, Brussels launched the Renovation Wave.
The goal is to double the rate of energy retrofitting by 2030.

The priorities:

1. Reduce energy poverty.
   Retrofit public buildings (schools, hospitals, offices).

2. Decarbonize heating and cooling.
   
   
   

An aged building heritage

75% of European buildings are energy inefficient.
Many are over 50 years old and do not meet modern standards.

The challenge is enormous, but it also represents an economic opportunity: new technologies, jobs, and reduction of dependence on fossil fuels.

European funds

To support member states, the EU has put in place tools such as:

• NextGenerationEU.

• National PNRR.

• Structural funds for local interventions.

These are resources that allow families, businesses, and administrations to tackle complex projects with greater economic sustainability.

Tax incentives and bonuses for retrofitting

Incentives are the key to making interventions affordable.
Without support, many families and businesses would not have the opportunity to invest.

Italy

• Ecobonus: deductions from 50% to 70% depending on the intervention.
  Superbonus: up to 110% for extensive works, available until the end of 2025 in reduced form.

• Conto Termico 3.0: refunds up to 65% for heat pumps, fixtures, and home automation.
  
  
  

Businesses and Transition 5.0

Companies can rely on the Transition 5.0 Plan, which provides:

• Tax credits up to 50% for digitalization and efficiency.

• Incentives up to 150% for advanced photovoltaic systems.
  
  
  

Europe

Each country has adopted its own tools:

• Germany: subsidized loans from the public bank KfW.

• France: direct contributions with “MaPrimeRénov’.”

• Spain: EU funds integrated with national plans.

The logic is always the same: reducing initial costs and accelerating the transition.

Innovative technologies for efficiency

Retrofitting is not just about walls and windows.
New technologies are revolutionizing how we consume energy.

Smart monitoring

Sensors and digital platforms allow you to:

• Analyze consumption in real-time.

• Identify waste.

• Optimize resource use.

Building automation regulates heating, cooling, and lighting based on external conditions and the presence of people.

Integration with electric mobility

Retrofitted buildings can become true energy hubs.

• Charging stations connected to photovoltaic systems.
  Batteries that store energy for vehicle charging.

• Energy exchange with the grid (smart grid).

It is a model that looks to the future, where buildings not only consume but actively produce and manage energy.

Long-term benefits

The effects of retrofitting go beyond the immediate.

Saving and independence

Consuming less means spending less.
Producing energy autonomously reduces dependence on fossil fuels and unstable markets.

Comfort and well-being

Spaces become more livable:

• Stable temperatures.

• Cleaner air.

• Quiet due to better acoustic insulation.

Property value

An efficient building is worth more.
With increasingly stringent European regulations, energy class will be a decisive factor in buying and selling.

Challenges and future prospects

The path is laid out, but obstacles remain:

• Bureaucracy: Complex procedures and long times often discourage citizens.
  Simplification is needed to make incentives more accessible.

• Awareness: Many do not know the real benefits of retrofitting or do not know how to start a project.
  Informational campaigns and dedicated consulting are essential.

• Digital innovation: The future is in smart buildings, capable of interacting with electrical grids and vehicles.
  The challenge will be to integrate different technologies, ensuring safety and reliability.

Towards a more sustainable future

Energy retrofitting is no longer an option but a necessity.
It reduces consumption, improves quality of life, and supports European climate goals.

Every intervention, big or small, contributes to building a more sustainable future.
A future where homes, businesses, and cities will not only be more efficient but also more resilient and competitive.