EV Charger Installation in Retrofits

Last updated: April 2026

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Quick Answer

Deep energy retrofits can cut heating and cooling energy use by 75% to 90% in existing buildings.
The EnerPHit Standard offers a quality-assured certification scheme for renovating existing buildings, ensuring high-performance upgrades.
Phius provides Phius CORE REVIVE and Phius ZERO REVIVE standards for upgrading existing buildings, focusing on advanced decarbonization and resilience.
The NextZero Program aims to help municipal light plants achieve net zero carbon emissions by 2050.

Upgrading an existing home for electric vehicle (EV) charging often means looking beyond just installing a new outlet. It involves a deeper look at the home's overall energy use and how it can become more efficient. We focus on deep energy retrofits, which aim to significantly reduce energy consumption, making homes ready for electrification and a future with EVs. These retrofits can lead to impressive heating and cooling energy savings, ranging from 75% to 90% in existing buildings. By improving insulation, airtightness, and windows, a home becomes a more stable and efficient environment. Programs like NextZero are already supporting municipal utilities in their goal to reach net zero carbon emissions by 2050, promoting all-electric appliances, heating/cooling systems, and vehicles. This commitment helps us build a carbon-free future.

What is a Deep Energy Retrofit?

A deep energy retrofit means making big changes to an existing home to cut down its energy use. It focuses on making the home much more efficient, often aiming for significant savings in heating and cooling. This kind of upgrade helps prepare a home for an all-electric future, which includes adding EV charging.

When we talk about deep energy retrofits, we mean more than just swapping out a lightbulb. We are looking at the entire building envelope and its systems. The goal is to reduce the energy a building needs by a large amount. This is a crucial step for any home looking to install an EV charger and manage its electricity demand effectively. By making the home itself more efficient, the additional load from an EV charger becomes easier to handle without straining the grid or increasing utility bills excessively.

Achieving Major Energy Savings

Deep energy retrofits can achieve significant heating and cooling energy savings. These savings are between 75% and 90% in existing buildings. This level of reduction transforms a home's energy profile, making it much cheaper to heat and cool. For example, a home that once spent hundreds of dollars a month on heating might see those costs drop dramatically after a deep retrofit. This is not just about comfort; it is about making the home's energy consumption predictable and manageable, especially when adding new electric loads like EV chargers.

Preparing for Electrification

A deep energy retrofit lays the groundwork for full home electrification. This means moving away from fossil fuels for heating, cooling, and hot water, and instead using efficient electric systems. When a home is highly energy efficient, these electric systems, including EV chargers, can operate with less overall impact on the home's energy budget. An EV charger, especially a Level 2 charger, adds a substantial load to a home's electrical system. If the rest of the home is still highly inefficient, this added load can push total energy consumption much higher. However, with a deep retrofit, the home's baseline energy use is so low that the EV charger integrates more smoothly.

The "Do It Right" Philosophy

The general approach to deep energy retrofits emphasizes quality and long-term results. "If you do it, do it right!" is a key principle when tackling these projects. This means investing in high-quality materials and skilled labor to avoid future problems and ensure the retrofit performs as expected. Shortcuts can lead to poor performance, wasted money, and the need for more repairs later. A properly executed deep retrofit ensures that all components work together to create a truly energy-efficient and resilient home. This is particularly important when considering the integration of new technologies like EV charging, where the electrical system needs to be robust and reliable.

What are Passive House Standards for Retrofits?

Passive House standards for retrofits provide a clear path to significantly improve existing buildings. The Passive House Institute (PHI) created the EnerPHit Standard specifically for renovating existing buildings. Similarly, Phius offers Phius CORE REVIVE and Phius ZERO REVIVE standards, which guide upgrades to existing buildings to achieve very high performance levels.

These standards are not just about saving energy; they are about creating healthier, more comfortable, and more resilient homes. When we talk about retrofits, we often consider a range of improvements, but Passive House standards offer a comprehensive, integrated approach. They ensure that all upgrades work together to maximize efficiency and performance. This holistic view is critical for homes that will host EV chargers, as it ensures the entire energy system is optimized.

The EnerPHit Standard

The EnerPHit Standard is the Passive House Institute's quality-assured certification scheme for renovating existing buildings. It recognizes that reaching the full Passive House Standard can be tough for older homes, even with plenty of money. So, EnerPHit offers a practical goal that still achieves excellent results. This standard can be applied all at once, or it can be done in phases using a detailed EnerPHit retrofit plan. This flexibility makes it accessible for many homeowners who might not be able to afford a complete overhaul immediately.

EnerPHit focuses on several key areas:

Improved thermal performance: This means making the building's shell—walls, roof, floor—much better at keeping heat in during winter and out during summer. This improvement is similar to what you'd find in a new Passive House building.
Considerably improved airtightness: Stopping uncontrolled air leaks is vital for energy efficiency and comfort. Blower door testing plays a big role here to measure and verify airtightness.
Use of high-quality windows: Installing Passive-House-suitable windows is a must whenever the chance comes up. These windows have multiple panes and special coatings to prevent heat loss or gain.

By addressing these elements, EnerPHit ensures that the renovated building operates with significantly less energy. This reduced energy demand makes it much easier to integrate new electric loads like EV chargers without major strain on the home's electrical infrastructure.

Phius Retrofit Standards: CORE REVIVE and ZERO REVIVE

Phius also offers its own set of standards for upgrading existing buildings: Phius CORE REVIVE and Phius ZERO REVIVE. These provide a path for transforming our current housing stock towards advanced decarbonization, resilience, and health. The Phius CORE REVIVE standard sets a high bar for energy efficiency, while Phius ZERO REVIVE goes further, aiming for net zero energy use. This means the home generates as much renewable energy as it consumes over a year.

A course from the U.S. Green Building Council, titled "Intro to Passive House Certification for Existing Buildings," helps people understand these pathways. It highlights how Phius certification can greatly improve indoor air quality and overall health in retrofitted buildings. It also analyzes the safety benefits, which strengthen the structural integrity and resilience of existing buildings against environmental challenges. This course, created by the GreenHome Institute, helps spread knowledge about these important upgrades. Intro to Passive House Certification for Existing Buildings | U.S. Green Building Council

These Phius standards are crucial for homeowners looking to future-proof their homes and contribute to a more sustainable future. By reducing energy demand and integrating renewable energy, homes become better equipped to handle new technologies like EV charging, contributing to a truly carbon-free lifestyle.

Why are Retrofits Important for Decarbonization?

Retrofitting existing homes is incredibly important for reducing carbon emissions and moving towards a net-zero future. Our existing buildings represent a huge part of our energy consumption and carbon footprint. Upgrading them helps us achieve bigger goals for the planet.

When we talk about decarbonization, we mean reducing or eliminating carbon dioxide emissions. For homes, this means using less fossil fuel for heating, cooling, and electricity. Retrofits help achieve this by making homes so efficient that they need very little energy, and the energy they do need can come from clean, renewable sources. This is a critical step in the bigger picture of fighting climate change and creating sustainable communities.

Meeting Net Zero Goals

Many communities and organizations have set ambitious goals for decarbonization. For example, the NextZero Program supports municipal light plant carbon emissions reduction goals of net zero by 2050. This means that by 2050, these utilities aim to have no net carbon emissions from their operations. To reach this, they encourage customers to make their next appliance, heating/cooling system, and vehicle all-electric. This transition to electric systems, powered by increasingly clean grids, is at the heart of decarbonization. For more details, see Passive House retrofit standard.

Retrofitting homes is a direct way to support these goals. By reducing the energy demand of individual homes, the overall load on the grid decreases. This makes it easier for utilities to transition to renewable energy sources, as they have less total power to generate. It also means that when homeowners install EV chargers, the electricity used to charge their vehicles is more likely to come from clean, low-carbon sources.

Improving Health and Resilience

Beyond energy savings and carbon reduction, Passive House retrofits offer significant benefits for indoor air quality and overall health. Old, leaky homes can have problems with drafts, moisture, and poor ventilation, which can lead to mold, allergens, and uncomfortable living conditions. A deep retrofit, with its focus on improved thermal performance and airtightness, creates a much healthier indoor environment. It ensures fresh air is brought in through controlled ventilation systems, while pollutants are kept out.

These retrofits also enhance the structural integrity and resilience of existing buildings against environmental challenges. Stronger insulation and better air sealing can protect homes from extreme weather conditions, making them more comfortable during heat waves or cold snaps. This resilience is increasingly important as climate patterns shift. A more robust building envelope means less risk of damage from moisture intrusion or temperature fluctuations. By making homes healthier and more resilient, retrofits contribute to a higher quality of life for residents and a more sustainable community. The USGBC course on Passive House certification for existing buildings, which has seen 147 completions, specifically highlights these benefits, showing a growing recognition of their importance.

How Does EnerPHit Certification Work?

EnerPHit is a certification standard created by the Passive House Institute specifically for renovating existing buildings. It provides a quality-assured way to ensure deep energy retrofits meet high performance goals. This certification helps homeowners know their renovation is truly effective.

The EnerPHit Standard is designed to be flexible. It can be applied to a renovation project completed all at once, or it can guide a phased approach. A phased approach uses an EnerPHit retrofit plan. This plan breaks down the renovation into smaller, manageable steps. This is helpful for homeowners who might not be able to do everything at once due to budget or logistical reasons. Each phase is planned to contribute to the overall goal of reaching the EnerPHit standard, ensuring that early improvements don't hinder future ones.

Key Components of EnerPHit

EnerPHit focuses on several critical areas to achieve significant energy savings and improved comfort. These components work together to create a high-performance building envelope:

Improved Thermal Envelope

The thermal envelope refers to all the parts of the building that separate the inside from the outside—the walls, roof, floor, and windows. EnerPHit demands improved thermal performance, similar to the levels found in new Passive House buildings. This means adding substantial insulation to walls, roofs, and foundations. The goal is to minimize heat loss in winter and heat gain in summer, keeping indoor temperatures stable with less energy. This creates a much more comfortable living space and reduces the load on heating and cooling systems.

Considerably Improved Airtightness

One of the most effective ways to save energy and improve comfort in an existing building is to make it more airtight. Old homes often have many small cracks and gaps that allow uncontrolled air to leak in and out. This "air leakage" wastes a lot of energy and can bring in moisture and pollutants. EnerPHit requires significantly improved airtightness. Builders achieve this by carefully sealing all gaps and penetrations in the building envelope. A blower door test is used to measure how airtight the building is and confirm it meets the standard. Better airtightness also helps control indoor air quality when combined with a balanced ventilation system.

Use of High-Quality Windows

Windows are often a weak point in an older home's energy performance. They can lose a lot of heat or let in too much sun. EnerPHit emphasizes the use of Passive-House-suitable windows whenever the opportunity arises. These are typically triple-pane windows with low-emissivity coatings and insulated frames. They are designed to minimize heat transfer, reduce drafts, and block unwanted solar gain. Upgrading windows is a visible and impactful part of an EnerPHit retrofit, improving both energy performance and the home's appearance.

The EnerPHit Retrofit Plan

For homeowners choosing a phased approach, the EnerPHit retrofit plan is essential. This plan outlines the sequence of upgrades, ensuring that each step contributes efficiently to the final certification goal. It helps avoid "lock-in" effects, where an early upgrade might make a later, more effective upgrade impossible or much more expensive. The plan considers the specific conditions of the existing building, local climate, and the homeowner's budget. It ensures that the project is cost-effective and achieves high quality solutions. As Bastian 2022 stated regarding deep energy retrofits, "If you do it, do it right!" This philosophy is central to the EnerPHit planning process, making sure every investment counts towards a truly efficient and comfortable home. Understanding the EnerPHit standard is key for any homeowner considering a deep energy retrofit for their home, especially if they plan to add an EV charger. You can learn more about the Passive House standard for retrofits at EnerPHit: The Passive House Standard for retrofits [Passipedia EN].

What Skills Do Retrofit Experts Need?

Retrofitting existing buildings to high energy efficiency standards like EnerPHit or Phius REVIVE requires specialized knowledge and skills. It's not the same as building new. Both tradespeople and designers/consultants need specific training to do the job right.

The Passive House Institute offers certifications to ensure professionals have the necessary expertise. These certifications help us know that the people working on our homes understand the complex science behind building physics and energy efficiency. They also understand how to apply these principles to older structures, which often have unique challenges. This expertise is vital for ensuring that a retrofit actually delivers the promised energy savings and comfort improvements.

Skills for Passive House Tradespeople

Passive House Tradespeople need to be skilled in the practical application of energy-efficient construction techniques. They can prove their knowledge and skills regarding the highly energy-efficient retrofit of small projects by passing a special online exam. This additional seal shows they understand how to implement the details that make a retrofit successful.

These skills include:

Understanding building envelopes: Knowing how to properly insulate walls, roofs, and floors to minimize heat transfer.
Achieving airtightness: Mastering techniques for sealing gaps and cracks to prevent air leakage, often involving specialized tapes and membranes.
Installing high-performance windows and doors: Ensuring these components are installed correctly to maintain thermal breaks and airtight seals.
Working with ventilation systems: Understanding how to integrate balanced ventilation systems to ensure good indoor air quality without wasting energy.
Problem-solving for existing structures: Adapting standard Passive House principles to the unique conditions and challenges of older buildings.

A valid Passive House Tradesperson certificate is a prerequisite for taking the retrofit expert exam. This ensures a foundational understanding of Passive House principles before specializing in retrofits.

Skills for Passive House Designers/Consultants

Designers and Consultants play a different but equally critical role. They plan and oversee the retrofit project. They also need to prove their knowledge and skills for highly energy-efficient retrofits of small projects through a further online exam. For more details, see Phius retrofit standards.

Beyond the basics, Designers/Consultants need advanced knowledge in several areas:

Passive House Planning Package (PHPP): They must have advanced knowledge of this software. The PHPP is a powerful tool for calculating a building's energy balance and predicting its energy performance. For retrofits, designers use PHPP to create "variant calculations," which help them compare different renovation options and see their impact on energy use. This allows them to choose the most cost-effective and impactful solutions.
Economic aspects of retrofits: Designers/Consultants need to understand the financial side of retrofits. This includes calculating return on investment, identifying available incentives, and helping homeowners make informed decisions about their budget. They can show how upfront costs lead to long-term savings.
Quality assurance aspects: Ensuring the retrofit is built to the highest standards is crucial. Designers/Consultants are responsible for setting quality benchmarks and overseeing the construction process to make sure these are met. This includes reviewing plans, inspecting work, and confirming that performance targets are achieved.

The GreenHome Institute created a course titled "Intro to Passive House Certification for Existing Buildings" which was published on June 13, 2025. This course provides an overview of retrofit standards from Phius, including the latest path for Phius retrofit certification with REVIVE 2024. Such courses are essential for professionals looking to expand their expertise in this growing field. For those interested in becoming a Retrofit Expert, the Passive House Institute offers resources and examinations. You can find more information about becoming a Retrofit Expert for Tradespersons and Designers/Consultants at Retrofit expert.

Can Any Home Become Net Zero?

Yes, with the right approach and technology, any home can become net zero. Net zero means that a home balances the power it needs with the renewable energy it can generate to match that need. It's about achieving energy independence and cutting carbon emissions.

The concept of net zero has become much more accessible thanks to advancements in heating technology and lower costs for renewable energy systems. This means that even older homes, which might seem like energy hogs, can be transformed. The key is a combination of deep energy retrofits to drastically reduce energy demand, followed by the installation of renewable energy systems, typically solar panels, to meet the remaining needs.

Understanding Net Zero

Net zero is a balance. It's not about consuming no energy at all, but about generating as much renewable energy as you consume over a year. For example, a home might use electricity from the grid during cloudy days or at night, but then send excess solar power back to the grid on sunny days. Over a 12-month period, the net amount of energy drawn from the grid would be zero. This approach helps homeowners significantly reduce their utility bills and their environmental footprint.

The path to net zero typically involves two main steps:

Reduce energy demand: This is where deep energy retrofits come in. By improving insulation, airtightness, and windows, and upgrading to efficient appliances and HVAC systems, a home's energy needs can be cut by 75-90%. This first step is crucial because it reduces the amount of renewable energy that needs to be generated, making the solar array smaller and more affordable.
Generate renewable energy: Once energy demand is minimized, solar panels are installed to produce electricity. The size of the solar system depends on the remaining energy needs of the home.

Efficiency Vermont notes that with new heating technology and lower-cost renewable energy systems, any home can get to net zero. You can read more about how to make your home net zero at How to make your home net zero.

Certifying Zero Energy Home Performance

Achieving net zero status is a significant accomplishment, and there are ways to certify this performance. Certifying zero energy home performance involves meeting specific building standards and undergoing verification processes. These certifications provide assurance that a home genuinely meets the net zero definition.

Programs like the DOE Efficient New Homes Program support the development of highly efficient homes. While this program focuses on new construction, the principles of high efficiency are the same for retrofits aiming for net zero. The Zero Energy Project also provides resources on certifying zero energy home performance, helping homeowners and builders understand the requirements and benefits. Certifying Zero Energy Home Performance - Zero Energy Project

By combining deep energy retrofits with renewable energy generation, existing homes can indeed reach net zero. This not only prepares them for new electric loads like EV chargers but also positions them as leaders in sustainable living.

— The Efficiency Team

Frequently Asked Questions

What is the difference between Phius CORE REVIVE and Phius ZERO REVIVE?

Phius CORE REVIVE and Phius ZERO REVIVE are both standards for upgrading existing buildings to high performance levels. Phius CORE REVIVE focuses on achieving significant energy efficiency, improving indoor air quality, and enhancing resilience. Phius ZERO REVIVE takes this a step further by requiring the home to generate as much renewable energy as it consumes over a year, effectively reaching net zero energy use. Both standards contribute to advanced decarbonization, making homes healthier and more sustainable.

How much energy can I save with an EnerPHit retrofit?

With an EnerPHit retrofit, you can achieve significant heating and cooling energy savings. These savings typically range between 75% and 90% in existing buildings. This drastic reduction in energy consumption is possible through measures like improved thermal insulation, considerably improved airtightness, and the installation of high-quality, Passive-House-suitable windows. The EnerPHit Standard focuses on creating a highly efficient building envelope, which dramatically lowers the energy demand.

Do I need a special certification to install EV chargers in a retrofitted home?

While the Passive House or Phius certifications focus on the overall energy performance of the home, installing an EV charger typically requires a licensed electrician. This electrician should be familiar with local electrical codes and the specific requirements for EV charging infrastructure. If the home has undergone a deep energy retrofit, its electrical system might need upgrades to handle the additional load of an EV charger. A "Retrofit Expert" certification, offered by the Passive House Institute, ensures professionals understand highly energy-efficient retrofits, which would be beneficial for integrating all new electric loads.

What are the main benefits of Passive House retrofits beyond energy savings?

Passive House retrofits offer several key benefits beyond just energy savings. They significantly improve indoor air quality, contributing to a healthier living environment by controlling ventilation and reducing pollutants. They also enhance the structural integrity and resilience of existing buildings, making them better able to withstand environmental challenges and extreme weather. Additionally, these retrofits lead to increased comfort, eliminating drafts and maintaining stable indoor temperatures. The USGBC course on Passive House certification for existing buildings highlights these improvements in health and resilience.

Where can I find training to become a Retrofit Expert?

The Passive House Institute offers training and examinations to become a Retrofit Expert. This includes separate pathways for Tradespeople and Designers/Consultants. Tradespeople can take an online exam to prove their skills in highly energy-efficient retrofits of small projects. Designers/Consultants also take an online exam, which includes advanced knowledge of the Passive House Planning Package (PHPP), economic aspects, and quality assurance. These certifications ensure professionals have the specialized knowledge needed for deep energy retrofits.