Passive House Standard for Home Renovation – The Best!

EnerPHit - The Gold Standard for Home Renovation.

If we want to significantly reduce energy use and CO2 emittance in the building sector a great opportunity is to find high impact solutions to transform our existing building stock into low energy and high performance buildings. I know, taking care of our old buildings is not sexy like designing new ones, but the key to a significant CO2 and energy reduction in the building industry lies with our old building stock.

In 1978, California became the first state to include energy requirements in its code, triggered by the oil embargo in 1973. As of March 1, 2015, 40 states plus Washington, D.C., have state-level residential building energy codes equal to or better than the 2006 International Energy Conservation Code (IECC), and 41 states plus D.C. have state-level commercial building energy codes equal to or better than ASHRAE 90.1-2004 (BCAP 2015a).

While this is an accomplishment it also means that there are still states without any energy requirements in their building code in 2018. And it means energy efficient measures in design, construction, systems and appliances were absent in many (most?) commercial and residential buildings constructed before energy efficient code requirements took hold in the 40 states who have adopted them.

Buildings that are 30+ years old are due for renovation of building components such as roof, exterior siding, windows and heating & cooling. This is the crucial moment to introduce the best energy efficient measures possible – at the time a building component is due to be renovated or replaced anyway.

Retrofits -all at once or step-by-step

While the best scenario for a building retrofit is to be performed all at once, the reality for most building owners however is that 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.

The time a building component is due to be renovated or replaced offers a great opportunity to not just replace the old component, but to improve its performance at the same time to the best standard available, not just passing the building code. For example, if the facade already needs to be renewed anyway, the extra effort for additional thermal protection of the exterior at the same time will be manageable since some of the cost is already associated with the renovation effort anyway (e.g. putting up scaffolding for exterior façade improvement).  

Each step will have a potential to provide big improvements to the building, in energy efficiency and comfort for its inhabitants.

But interdependencies exist between individual energy efficiency measure, e.g. making a building more airtight requires a ventilation strategy. Technical connection details must be developed that will work well during all phases, e.g. how to deal with old windows in a new exterior insulation layer and how to prepare for an optimal window placement once windows will be replaced in a subsequent step.

The challenge is to ensure that the retrofit measures implemented over time (maybe many years) work together to a maximum whole house deep energy retrofit at the end.

A well-thought-out master plan is not only indispensable for a good final result, it also helps keep the overall cost low. Costly alterations because of a short-sighted earlier measure can be avoided and energy cost are gradually reduced to a minimum.

What if we would create a master plan that lays out each step of the step-by-step retrofit in relation to each component lifespan?

What if we would create this master plan at the time we start with the first measure? That would allow us right there to think through interdependencies, challenges, budgets and timetables for all necessary building modernization measures over many years to come. That way we would already know the when, what and how much for all the subsequent next retrofit steps. We would know how much energy, CO2 output and money will be saved in total and over time with each step.

What if we could have this master plan certified by a third party using the world leading standard in energy efficient construction? A building standard that achieves ultra-energy efficient, comfortable, affordable, durable and ecological buildings, regardless of the regional climate.

You probably figured it out already – WE CAN! The Passive House Institute has developed a model to support the transformation of our existing building stock into a sustainable energy future – it is called EnerPHit.

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 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:   

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:

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 in 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)

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