Passive House is all about building science and the best path to a comfortable, high performance home.
Think about it, what if you would never have to turn on your heater or air-conditioner and be cozy comfortable in your home? What if you would not even have an AC or a heater? Sounds crazy?
We are so used to compensate poor design and building practices with mechanical heating and cooling that we equate comfort in our homes with the capacity of heaters and air-conditioners.
What if we instead would rely on a building’s proper design of the exterior enclosure to provide balanced temperature inside, no matter the temperature outside? Sounds crazy too?
Well, it’s not, it’s the correct way to build and to renovate. It’s smart and it’s quality. It creates a comprehensive comfort that cannot be accomplished with mechanical systems.
The trick is to find trade professionals, like architects and contractors, who understand and incorporate building science and up-to-date tools into their practice. Merely following the building code won’t be enough.
Professionals with well rounded knowledge in building science and skilled to incorporate site specifics and climate into their design to create the best performing home for you are not as common as you might think.
Beautiful design and knowledge of architectural styles is usually a main focus. Performance of the building usually only goes as far as the building code requests and that can be a pretty low standard dependent on where you live.
You think I am exaggerating?
Unfortunately I am not. I learned this the hard way.
A few years back I embarked on a house addition with south facing windows and sliding doors accompanied by a one foot overhang.
In the summertime, the room heats up very quickly, gets uncomfortable and air conditioning is needed.
If my architect would have done a sunlight simulation, it would have shown that the sun hits the glazing in the afternoon during summertime. He could have adjusted his design to avoid the heat gain during the summer month easily.
Based on the simulation he could have adjusted the already planned overhang by the right amount and I would have had a comfortable room without air conditioning all day and summer long. Easy fix if you have the knowledge at the right time in the project. Without the knowledge a performance loss with energy and money wasted all summer long.
An architect has to be able to calculate and design to protect windows from direct sunlight in the hot summer afternoons but not during colder winter month when you want the sun to hit the glazing and provide free heat and additional light.
It should be basic design guidelines in a hot climate but the trade professional has to have the skills to execute.
Trade professional who apply building science in their practice would have easily circumvented this shortcoming.
Another example is a roof replacement I had done years back. Once the roof was off, I could have replaced old insulation with a lot higher insulating material and air tighten the roof area at the same time.
I did not know to ask the right questions, we did not do any air sealing and a rather dismissal replacement of insulation in some places and in some parts not at all.
The trade professional did not have the knowledge to provide me with the best solution. And I had no basic knowledge of best building practices to be able to request the best solution.
If I would only have known back then what I know now, I would have a more comfortable home that requires no cooling and less heating.
This is why it is so important that we homeowners, or homeowners to be, have a solid understanding of how a house works.
We do not have to become DIY people – with enough knowledge to
- select the best trades professionals,
- ask the right questions,
- request the best options, and
- monitor the progress of the project,
we can have a decisive impact on the quality outcome of our home improvement projects and achieving our goals.
One of the reasons why I started my blog is to empower homeowners to initiate the right steps to close the gap between a code home and a superior sustainable home.
How do we get from a suboptimal house, merely built to code, to a high performance structure?
Welcome to The Passive House Standard!
The voluntary Passive House Standard is used all around the world and in all climates. It is considered The Gold Standard for the most comfortable and energy efficient buildings.
It can be used for all building types and architectural styles (residential homes, high rise residential, commercial buildings, schools). Anything that can be build can be built to the Passive House Standard.
But why not just build and renovate by code? Shouldn’t that be sufficient to get the best home possible? Why going the extra mile? A better question to ask is:
Would you like to have a home that is built for:
and that does all this with
- a lot less energy, like 75% less energy and
- it seeks a balance with nature?
A standard code home won’t cut it if you want a home like that. A standard code home makes sure the building is safe.
Dependent on where you live the local building code might have some green and energy efficiency measures or it might not. Most building codes fall way short of the guidelines to get you to a high performance home.
The Passive House Standard can be used to close the gap between standard code building and a high performance home with the benefits listed above.
It is a voluntary building concept that is based on the wisdom of building science and guided by 5 principles.
Here is a 90 second clip with a quick introduction to the 5 principles.
The 5 Passive House Principles
- Climate specific and continuous insulation,
- Continuous air-sealing (no worries, your airtight home will have better fresh air than a standard home does. And yes you can open windows, but you don’t have to open windows to get fresh air, e.g. when it’s hot/cold or polluted outside.),
- Minimalized or no thermal bridges (which are gaps in the insulation layer. E.g. a concrete floor slap that protrudes to the outside veranda or balcony and interrupts the insulation layer.),
- Airtight and insulated windows, and
- Energy Recovery Ventilators (ERV), that continuously filters air, balances heat between inside and outside, and regulates moisture.
Implementing these principles will minimize the need for mechanical systems to heat and cool your home.
Based on your local climate you will need to use these principles differently. E.g. a lot higher insulation value for roof, walls and floor are needed in colder climates. The airtight layer might be installed on the outside in warmer climates and inside in cooler climates.
The Passive House methodology and tools help your team to make the appropriate decisions.
All components are essential for new buildings as well as retrofit. It only works as a whole system, you can’t pick and choose.
Since you start with a blank piece of paper in newly builds it should not be hard for your skilled team to implement these components in your design and during construction.
In retrofit projects you have to deal with existing design and construction that might limit or make it cost prohibitive to get rid of all potential issues, such as thermal bridges, in the existing structure.
The Passive House Standard has an answer for exiting building too, more about it a bit later.
A skilled trade person understand all this and incorporates these principles in their design and construction/remodel.
Here is a comparison of a typical building and a Passive House building:
Passive House Performance
Besides applying the Passive House principles, rigorous performance criteria have to be met to call your home a Passive House. More important thought, these metrics are not arbitrary numbers thought out by some people.
These metrics are based on 25+ years of research and validation and should not be pushed aside lightly.
Achieving the metrics is critical to gain all the benefits listed at the beginning of this article.
The performance metrics are the same in all climates (with a slight difference for humid climates). The metrics are slightly different for remodels to acknowledge the difficulties some existing buildings might reveal.
Meeting these performance metrics depends on 4 pillars:
- application of all 5 principles,
- design of the building and application of the 5 principles,
- choice of building materials and
- an energy model that translates the impact of design and material choices into performance metrics.
The energy model, or Passive House Planning Package (PHPP), is a specific tool developed by the Passive House Institute.
Methodology and Tools
The Passive House methodology and tools provide guidance on how to unite the Passive House principles with the desired design, style and local climate.
Following these guidelines can result in reduced energy usage for heating and cooling by up to 90% of many standard code buildings.
Not like most other energy modeling tools the PHPP has proven to be very close to reality, as long-term studies of a vast amount of Passive House buildings have shown.
It is not required to prove the actual performance over a period of time if the performance metrics are met in the PHPP.
Yet, most Passive House owners measure the performance once they live in their homes and compare it with their model.
It’s the Passive House owners pride to live in a gold standard home!
Studies have shown that the biggest deviation between model and reality (better or worse) depend on the behavior of the occupants (e.g. a lot more than the planned gadgets and tools are constantly plugged in).
Passive House for Retrofits – EnerPHit
As I already mentioned, the Passive House program acknowledges the challenges that come with existing buildings.
Some required measures might just not be possible to achieve or can’t be accomplished completely. e.g., we can’t do much about an uninsulated floor of an existing slab on grade home.
For that reason, The Passive House Institute came out with adjusted performance indicators to take possible limitations in the retrofit building into account.
The Passive House Standard for Retrofits is called EnerPHit.
The best scenario for a building retrofit is to upgrade all components at once. however, the reality for most building owners 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.
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.
- A 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 energy saving measures with renovation measures that would have been necessary anyways. For example if the façade needs to be renovated, the additional cost for thermal insulation to the Passive House Standard is manageable.
EnerPHit provides a methodology and tools to plan years in advance to replace components of your building shell when they are due for major maintenance or replacement. At that point, instead of doing the “code improvement”, you remodel to Passive House levels.
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 and performance possible (situation and budget wise).
Get more detail in my article Passive House for Retrofits: EnerPHit
Passive House Classes
Renewable energy is the perfect complement to the ultra energy efficiency of a Passive House building.
The Standard provides 3 certification levels that can be used as guidance. The 3 levels differ on how much renewable energy production complements the energy efficiency of a building: Classic, Plus and Premium.
Classic represents the traditional Passive House building with optimized energy efficiency but no dedicated renewable energy production.
Plus and Premium, give projects recognition for the extend of renewable energy used for the building.
Passive House vs. Zero Energy Homes vs. Green Homes
Net zero energy or zero energy homes produce as much renewable energy as they consume over the course of one year. This is achieved by reducing the energy load of a building first and then providing renewable energy on site of the building for the remaining energy needs.
The Passive House Standard is the perfect approach to accomplish a zero energy home.
Green Homes follow the guidance of Green Building Standards with a broader goal. These Standards look at all area of a home, its interaction with nature and its occupants. Green Building Standards address:
- the place a home is located,
- water conservation,
- energy conservation,
- impact of materials on nature and occupants,
- indoor air quality,
- health and happiness and beauty that uplifts the of occupants, and
- support of a just equitable surrounding.
The Passive House Standard is unique among green building programs since it not only describe what makes a home high performance home (features and performance) it also provides a roadmap on how to get there.
Other green standards describe benefits and goals but don’t provide any methodology on how to accomplish these goals. They leave it to the creativity and insight of trade professionals to figure it out.
This is where Passive House is so genius. It tells you what to do and how to get there.
The Passive House Standard is based purely on building science and helps you to understand how your house works.
This is why it is the quintessential accomplice
- for every zero energy home project to conserve energy before adding renewable energy, and
- for any other green building standard with a wide range of sustainability goals. The Passive House standard covers green building goals like energy efficiency and comfort in the best way.
Going into a project with a base knowledge is vital to the success of any home project. The more educated you are, the better you can make sure the project develops into a successful final product – the way you envisioned it.
My Passive House Resource Library provides you with a treasure trove of information and resources for everything related to your home’s enclosure: like roof, walls, floor, windows and doors and all your mechanical systems.
Check it out and dive deeper into the topic.