Building a new home and making it as comfortable and efficient as possible --- that's our dream! We are also firm believers in doing things right and for the right reasons. On our journey to our future dream home, these principles have led us to specifying a Passive House.
This sounds simple enough, but in the discussions with our builder and the Passive House consultant, we learned that this goal isn't necessarily so easy to implement. The questions quickly became: Is this even achievable? And if not, what are the alternatives?
At the end, we settled on the Passive House certification, with a loop hole for EnerPHit if performance criteria are impossible to meet. For this, you will need to know that our home will be a "significant renovation" by re-using two of the existing side walls as part of the new building.
Passive House and EnerPHit share the same principles
First of all, both certifications are issued by the Passive House Institute.
Secondly, all the major design principles that are typically applied for a Passive House are also applied for an EnerPHit house:
minimizing thermal bridges
an almost airtight building envelope
using high quality windows and doors
air ventilation with a heat recovery system
efficient heating and/or cooling
opting for renewable energy sources, if desired and if aiming for plus or premium certification classes.
Finally, all the processes from design over construction details to actual performance testing are applied for both certifications.
So in a lot of ways, the two certifications are very much alike.
Passive House and EnerPHit differences
For the most part, Passive House is best suitable for new construction houses because all the design principles mentioned above need to work in unison for the best possible building performance overall.
Passive House requirements and performance levels are very strict. In terms of energy efficiency, Passive House is a very sustainable building standard that offers up to 90% primary energy savings compared to a standard home.
It is not always practically possible or cost effective to apply the same criteria for renovations or retrofits, because pre-existing building elements need to be integrated into the design concept. This is where the EnerPHit program comes in. It allows for slightly more relaxed performance requirements and therefore design flexibility, whereby still using the same principles and building components. Energy efficiency under EnerPHit is still marketed at 75 to 90% over a standard home, and many EnerPHit houses have done very well in their actual performance tests.
Building Performance Details
There are many aspects to consider as part of the Passive House design. However, there are two main criteria that stand out and are measured at the end to define the building's performance:
Energy demand for heating & cooling (primary energy demand)
The energy demand is measured in kWh per square meter. kWh stands for kilowatt hour. For perspective, 1 kWh will power your LED TV for 60 hours, run your laptop for an entire day or do about half a load of laundry in your washer... The average Canadian household consumes somewhere around 11,000 kWh per year.
Airtightness is measured in ACH50 or n50 h-1 (???). This stands for air changes per hour (ACH) at 50 Pascal pressure. It means the amount of airflow through the building's envelope or the building's shell, if you will. The lower the value, the less air has escaped and the better the result. This is typically measured with what's known as a blower door test.
Performance in comparison
How do the two certification stack up in actual performance values?
Clearly, Passive House is superior to EnerPHit by meeting the tighter performance criteria!
EnerPHit buildings certainly have their space for the flexibility that is allowed when using existing building sections during a renovation. It is a very energy efficient certification and far superior to many other sustainable building standards.
Note that renewable energy criteria are deliberately omitted from this overview as they won't immediately apply to our project.
EnerPHit is simply not as known or common as the term Passive House. Since the certification body is the same in Passive House Institute and the same principles are being used, we even find that both certifications are used almost synonymously, sometimes in a misleading way. So if you're in the market for a Passive House, be sure to ask for the actual certificate or registration.
While both certifications have their value in the market, we believe that the average consumer in North America is guided more by labels than by performance values. This is not meant negatively, but more as an account of the current and near term lack of energy efficiency knowledge and certification in the market. In contrast, the Energy Pass or Energy Certificate for new homes has been in effect since 2009 in the EU and is easily usable for both sellers and buyers to indicate the actual performance of a home. For the lack of such transparency in Canada alone, Passive House is the stronger label to hold for future resale value of our house. And we strongly believe in the evolution of our market for this label to just grow stronger in future.
At the end of the day, this is what we like to see in our entryway:
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