Passive House Retrofit: EnerPHit

  • Post category:Building
  • Reading time:15 mins read
Passive House Retrofit: EnerPHit

Your Remodel – Pathway to a superior Sustainable Home

So the external structure of your home needs repair or more serious updates? Maybe you even decided to retrofit one or multiple elements to make your home more energy-efficient?

You wonder how your home improvement project can maximize your home’s performance to benefit the health and comfort for you, your loved ones and the environment?

If your home project involves in any ways the exterior structure of your home, like a roof, exterior walls, windows and doors or the mechanical systems like heating and cooling then this article is for you.

Here are a different types of scenarios I can think off:

Remodel: Renew components or change the footprint of your building enclosure. Maybe a roof has to be replaced, you decided to finally replace these drafty single pane windows, upgrade your dated sidings with a modern look, or you are planning an addition? There are many reasons to touch the exterior structure of your home.

Retrofit: Convert your home into a Sustainable & High Performance Home. Maybe your goal is not any one component but rather to reduce your energy bill, make your home more comfortable with less maintenance? A high performance home that has an excellent building enclosure accomplishes that. It is airtight and insulated well, and has properly sized, installed, and commissioned heating and air conditioning systems. 

Replace Materials: Avoid toxic building materials in all. You decided to be more thoughtful in your choices and go with non-toxic and sustainable materials and products.

No matter what your reasons for your home improvement project are, as long as you plan to touch the exterior structure of your home or a main mechanical system of your home you have a choice.

You can either stay merely in line with your local building code or you can go beyond building code and upgrade your home with high performance components and building practices to get maximum benefits as a result. You will enjoy enhanced comfort, health, ultra-energy efficiency, and much more.

You might think well, doesn’t our building code ensure we have the best buildings that can be build?

Unfortunately, this is not the case. Depended on where you live, your building code might primarily focus on building safety and not necessarily on your enhanced comfort, health, energy efficiency, nor give much consideration to  the environment.

It’s a bit like choosing your food. You can just rely on any food approved by the Food and Drug Administration (FDA) or you can step it up, get educated what is healthy and good for your health and choose accordingly.

The FDA focuses on food safety but not necessarily the quality of the products offered in your grocery store.

Same is true in the building Industry!

Building to code is obviously a must and ensures building safety but it can also be the bare minimum, dependent on the state you live in.

For our home remodel projects it is up to us to strive for the building products, processes and professionals that provide us with the most benefits.

Like with food choices, to make the most beneficial decisions for your home, you have to gain some basic building knowledge first.

That brings me to the 5 top things to do to get educated and close the gap from a standard code home to a high performance home.

The top 5 Things to get a High Performance Remodel

1. The Passive House Standard & Remodel EnerPHit

The voluntary Passive House Standard is a great opportunity to learn how your house works. The Standard guides you on how to close the gap between a standard code home and a high performance home for everything related to the design and construction of your exterior structure and mechanical systems.

Not saying you should become an expert but get a basic understanding about the 5 Passive House Principles and why they are so important to follow.

This article is a good start with links to more: What is the Passive House Standard?

For starters a quick 90 seconds introduction:

How to apply the Passive House Standard to a Remodel?

While the Passive House Standard focuses on new buildings, there is an adjusted version available that takes the difficulties of an existing building into account. This version of the Passive House Standard is called EnerPHit. 

EnerPHit addresses the challenges of a remodel that might have to deal with:

  • Existing architecture,
  • Fixed forms,
  • Fixed orientation,
  • Neighboring buildings,
  • Planning and conservation issues, and
  • Existing occupants.

EnerPHit is still founded on the original 5 Passive House  Principles, it acknowledges that it might not be possible to achieve them completely, e.g., we can’t do much about an uninsulated floor of a slab on grad home.

For that reason, EnerPHit comes with adjusted performance goals to take those possible limitations in the retrofit building into account.

As with everything The research organization behind the standard, the Passive House Institute, developed EnerPHit based on research and experience.  

EnerPHit also addresses a common dilemma for renovations, it is mostly impossible to retrofit the whole exterior structure to all 5 principles at the same time. Most of the times it is financially and logistically not feasible to complete an entire deep energy retrofit in one step.

In fact, 80-90% of all retrofits undertaken are partial retrofit measures rather than complete one-time deep energy refurbishments. These partial retrofit measures are completed over time when the respective building component needs to be renewed anyway.

That is why EnerPHit provides guidance for both scenarios:

  • Retrofit all components of the building shell in one step to the EnerPHit Passive House Standard.
  • step-by-step approach to retrofit all components of the building shell over time, based on a schedule created at the time the first renovation step is planned.

To achieve cost efficiency, it is crucial to couple the high performance and energy saving measures with renovation measures that would have been necessary anyways.

The motto is: If you do it, do it right! 

Whenever a building component needs to be replaced, the materials used and the workmanship involved should be of the highest quality possible. 

Get more detail about guidelines and tools in my article Passive House for Retrofits: EnerPHit.

For starters a 6 minute video about a step-by-step retrofit of a family home.

2. Home Performance Assessment

The sooner you have a good understanding of your home’s current condition and opportunities for improvement, the better you can plan future home maintenance and remodel projects.

So, get a health check for your house… It is called either a Home Performance Assessment or Energy Efficiency Audit.

Select Certified Energy Auditor or Assessor to perform the home assessment. Here is a list of things a good auditor will do:

  1. Determines the  overall condition of your home:
  • for each of the components that make your exterior structure (roof, exterior walls, floor, windows and doors),
  • for the mechanical systems  (heater, air-conditioner, water heater, etc.) and
  • how effective all of these components work together as a whole house system.
  1. Runs safety checks and diagnostic testing to identify leaks as well as moisture and ventilation problems. This includes a so called blower door test to identify air leaks and thermal imaging with an infrared camera to detect breaks in the insulation layer.
  2. Conducts an interview with you and preferably all other occupants, to identify comfort specific issues as well as living pattern in your home. If you are planning a remodel a home you have not lived in yet, make sure you talk to the previous occupants and also get access to their energy bills or at least totals per month if possible.
  3. Reviews previous energy bills as a benchmark for projected improvements and savings.
  4. Provide you with a prioritized list of home improvement recommendation, prioritized based on health and safety issues, comfort and overall cost benefit.

This gives you a clear understanding of your buildings condition. It is always good to be in the knowing, even if it is not pretty! 

Purely anecdotal information, like ‘the upstairs bedrooms overheat while downstairs never gets warm’ won’t cut it. This comfort issue is important to know but it won’t tell you the real problem within the building structure and how you can improve it.

With this clear understanding of your home’s condition, you can make better decisions and incorporate these findings into your overall remodel plans.

EnerPHit has a few tool to document these findings:

  • to create a schedule for all different elements of your exterior structure and mechanical systems,
  • to create an energy model to determine the baseline, the performance values for your home’s current condition,
  • to play around about solutions
  • to create scenarios for either a one step renovation or a multi-step-approach.
  • and create a step-by-step-retrofit plan if it is not feasible to do it at once.

Review my article Passive House Retrofit: EnerPHit for more details.

3. Select a Qualified Team

Certified Passive House Consultant

The first and most important step is to find a good Certified Passive House Consultant and bring them into your team right at the beginning of your project.

They have a profound knowledge about the physics of building performance, best practice for your building type and region as well as access to the tools of the trade such as the energy modeling software used to quantify and verify the performance and cost of materials and products. They will  be able to model different options to come to the best result for your goals.   

It all starts with the baseline model that reflects the current performance of your home. It serves as the starting point for potential improvements in one step or multiple. This initial model is based on the results of your home assessment.    

You will want to rely on this team member early and often to gain an understanding of how your building is improving whether you are on target for the performance goals the Passive House Standard has set.

A important team member to ensure the highest quality of the remodel.

Get estimates from at least 3 qualified professionals. Make sure you search for Certified Passive House Consultants certified by the Passive House Institute  Always ask for samples of previous audits and references from their customers. And remember the cheapest is not always the best choice although it can if all else is superior to the others. 

Certified Energy Auditor 

As mentioned in the previous chapter you need to hire an energy auditor to create the outlined home performance assessment.  The energy auditor should come with solid credentials, references and experience in residential energy audits. 

This might be the same person as the Passive House Consultant. When you select your Passive House Consultant verify with them if they also do the home performance assessment. 

If they don’t do it, ask who they work with and inquire for 3 recommendations. Or maybe they even partner with an energy auditor.

If the home assessment is not done by the Certified Passive House Consultant make sure they work closely together and the Passive House Consultant gets all the information they need to create the baseline energy model. 

This is why it is important to make the Passive House Consultant your first hire. 

Do plenty of research and get estimates from at least 3 qualified professionals. Always ask for samples of previous audits and references from their customers. And remember the cheapest is not always the best choice although it can if all else is superior to the others. 


Dependent on the size of your home remodel you might hire a general contractor or sub contractors for specific components such as the roof. 

Since you want to make your remodel a high performance remodel you need to find a contractor who is knowledgeable and experienced in remodeling homes to ultra-energy efficient standards or to zero or near zero energy homes.

The contractor should be knowledgeable and experienced with:

  • Air seal techniques and products,
  • Continuous insulation strategies and materials,
  • Blower door equipment to verify the energy auditors air leaks, run tests during the air sealing process to re-check and reseal any leaks as many times needed to reach you airtightness goal,
  • High performance, airtight windows and proper installation techniques,
  • Most effective mechanical systems (heating, cooling, ventilation) and appliance.
  • Cost effective measures and product lines to stay on budget. 
  • Available energy efficiency incentives, rebates by local utilities, municipality, and tax incentives by state or federal authorities.

Again, plenty of research and interview at least three contractors. Provide them with the home assessment report, invite them to do their own home evaluation and have them give you a preliminary estimate as part of the selection process. 

Passive House Consultant or Designer

The most important step to reach your high performance goals as outlined by the Passive House Standard is to find a good Certified Passive House Consultant. Make them part of the process as early as possible.

The Passive House consultant needs to work closely with the home energy auditor. Best scenario is of course if the PH consultant can do the initial home assessment as well.

A certified passive house consultant will work with all your other team members to gather information, make recommendations and  

EnerPHit Logo

EnerPHit is one of the most stringent and integrated standards available internationally for energy retrofits. The EnerPHit Standard is based on the Passive House Standard, a tried and true approach to efficient building with over 20 years of positive examples to show and used all over the world for any type of building.

Schedule that shows the life cycle of each building component with planned retrofit dates associated:

EnerPHit Scheduler

EnerPHit Retrofit Plan

EnerPHit is a methodology that allows to plan and manage a deep energy retrofit over time, step-by-step. An overall plan will be prepared for the first and all subsequent modernization steps at the same time. This is the only way to be sure that everything fits together, is most cost effective and the building owner can count on having an increasingly more comfortable building with low energy cost over time.

An EnerPHit Retrofit Plan (EPR) is composed of:

  • a timetable that provides an overview of the chronological sequence of renovation measures that are necessary anyway over the years (e.g. new roof);
  • more detailed information about the expected renovation measures and the added retrofit step;
  • investment, maintenance and energy cost for renovation and retrofit measures;
  • characteristic values of building components used;
  • achievement of EnerPHit criteria;
  • matrix with interdependencies between measures that need to be address;
  • detail drawings and explanatory notes.

The outcome is a well-thought out master plan called EnerPHit Retrofit Plan (ERP).

For architects and energy consultants the ERP is a great tool for efficient and well-structured planning of step-by-step retrofits. The building owner receives a copy of the ERP to keep for future references. If the building gets sold, the ERP helps the new owner to understand the additional energy efficiency potential of the building and the measures associated.

Example of a step-by-step EnerPHit Retrofit designed to EnerPHit Premium certification:   

PH Energy Demand

The EnerPHit methodology and toolset can be used without intended EnerPHit certification.

EnerPHit Pre-Certification

On the other hand if EnerPHit certification is pursued, a pre-certification can be achieved for quality assurance and recognition. A PHI accredited certifier will check the prepared EnerPHit Retrofit Plan for compliance with EnerPHit requirements, for completeness and consideration of all interrelations between all measures. This way unnecessary investment and energy cost can be avoided. After approval, the first set of measures can be implemented. Once the step is executed and approved by the certifier the building owner will receive a pre-certification for the building.

A preliminary certificate might increase the value of the building because its potential is clearly demonstrated and validated by a third party. It also increases the credibility of the refurbishment concept in the context of talks with the bank e.g. because the achievable cost saving is available in a reliably calculated way.

With or without certification, a high-efficiency retrofit to the EnerPHit standard differs from standard retrofits in a higher quality of design, workmanship and construction components, which leads to a more comfortable building, higher energy efficiency and less CO2 emission.

Process of a EnerPHit certification over time – step-by-step:

EnerPhit Process

What if our government, states, municipalities would adopt EnerPHit? What if our architects, developers and contractors would adopt the Passive House Standard and it would be the way they design, build and retrofit buildings – every single one? For me that is the goal. The Passive House Standard should be the way we build, period!

There is no alternative to Passive House.

My own foray into EnerPHit

Using the EnerPHit toolbox , I created a master plan and first step for an EnerPHit step-by-step retrofit of a 1948 ranch style residential building. Multiple renovation steps have already occurred in the past without any deep energy efficient measures in mind; only the energy measures required by the building code had been applied. The goal is to transform this house into a nearly zero energy home that provides high comfort all year around without any, or very minimal heating and cooling and a small amount of solar panels to energize the electrified home and two electric cars. I am using EnePHit to get there, cost effectively. I will report on the results in another blog post.

In the meantime, check out this article about the brownstone in Brooklyn that was retrofitted using the Passive House Standard (albeit not step-by-step and from 2014).

How a Brooklyn brownstone became a low-energy passive house

The numbers of Passive Houses in North America mentioned PH SFin the article is a bit outdated. It has changed dramatically between 2014 and now, see diagram to the right. Especially in the years after 2014 the growth has been exponentially.

Photo credits – All images related to EnerPHit: Passive House Institute . The exponential growth curve: North America Passive House Network (NAPHN)

Leave a Reply