Often times we are asked what defines a Passive House. Check out this awesome interactive map on the Passive House Institute website that describes the various components of a house and how they all play a role in creating a Passive House (screenshot below). Houses are like human bodies – in order to have a healthy home, every component is important and affects the health of the overall system.
Archive for ‘Energy’
At Long last, the case has been settled as to the definition of what a “Zero Energy Building” is. The U.S. Department of Energy (DOE) recently released an extremely important report entitled, “A Common Definition for Zero Energy Buildings” that will settle once and for all what constitutes a Net-Zero Energy Building.
Four of the most important factors established in the report as to what is required for a building to be Zero Energy are:
A building needs to demonstrate over 1-year that it has used no more energy than it has generated with on-site renewables. Thus, there is now no such thing as “designing and building” a Zero Energy Building, it cannot be called that until at least 1-year after commissioning and occupancy.
ALL types of energy used, not just electricity, factor into the Zero Energy Building Calculations. The calculations take into account the use of natural gas, propane, biogas, etc.
Source Energy values, not Site Energy, is used for the Zero Energy Building Calculations. Simply put, Site Energy is the energy used on site, and Source Energy is the sum of all energy required to get the energy onto the site as well as the energy consumed on site. Example: For each kWH (kilowatt hour) of imported electricity used by a building, the energy required to provide that single kWH is 3.15 kWH. For each therm of natural gas imported the source energy is 1.09 kWH. The report provides all the Source Energy Conversion Factors. The good news is that renewable energy exported uses the same conversion values.
“Renewable Energy Certificates” (REC’s) cannot be used in the calculations. Only on-site generated renewable energy can be used in the calculations.
It’s important to note that the DOE established that the word “Net” really is not required, and so “Zero Energy Building” suffices.
So, there are a lot of buildings that have been claimed to be “Net Zero Energy” that cannot now make that claim. They may only have shown that they are Net Zero through modeling, not demonstration. Furthermore, there are purported NZE buildings that have not accounted for energy other than electricity.
We applaud the DOE for ending the confusion and arguments as to what constitutes a Zero Energy Building. Its position is more in alignment with the philosophy of the most rigorous green building certification program in the U.S., the Living Building Challenge, in that buildings need to demonstrate their performance for a year before certification is granted.
We should all put the goals of meeting government mandates for achieving Zero Energy Buildings into a new perspective based upon the DOE definitions. It’s not going to be as easy as a lot of people may have thought it was going to be. And that’s a good thing.
We hope that someday there is a full accounting for the True Cost of energy, not the Partial Cost. The True Cost takes into account the cost to the environment (and to humanity) of generating and consuming energy. Yes, that includes the carbon generated and put into the atmosphere. Zero Carbon Buildings? We shall see.
We learned so much at the Project Partner Workshop last week, and we hope you did too! A HUGE thanks to our project partners for coming out and teaching us about leading edge sustainability techniques in their fields.
Enjoy the pictures below 🙂 click to enlarge the thumbnails, and click the “i” in the enlarged photos to view the captions.
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Our awesome Project Partners:
We had a great day yesterday showing you all the unique features at our Casa Aguila and Greisman projects! Thanks so much for coming out, we hope you had a good time and were able to stop by the other great projects as well.
Very exciting things happening at Casa Aguila! We craned in 3 dual-axis solar trackers, which will each hold 24 panels to create a 22.7 kW PV system. These trackers are huge – they measure about 27 feet across and 17 feet deep! They rotate on a dual-axis so they can detect the maximum point of light irradiance every day.
Domenico Feo, founder of Zehnder Nestsystems, provided a presentation to us and the Passive House Alliance of San Diego on Radiant Heating/Cooling utilizing hydronic ceiling panels, coupled with dehumidification that is incorporated into the Zehnder HRV/ERV ventilation system.
Domenico is with the Zehnder Group Italia (Italy) and is planning to soon move to California. His ComfoDew system for dehumidification has been included in the Ramona “Casa Aguila” Passive House Project. We recorded the broadcast and will broadcast his presentation nationally to all PHAUS members in a GoTo Webinar.
Domenico is full of extremely interesting information that he can pass on to us, such as why it is better to put radiant heating/cooling in the ceiling rather than in the floor, why absolute humidity is what we should be concerned with rather than relative humidity, etc.
At our Casa Aguila project in Ramona, we are working towards building San Diego County’s first Certified Passive House. Here’s a little bit about the passive design, first developed in Germany:
- It employs continuous insulation through its entire envelope without any thermal bridging.
- The building envelope is extremely airtight, preventing infiltration of outside air and loss of conditioned air.
- It employes high-performance windows (typically triple-paned) and doors
- It uses some form of balanced heat- and moisture-recovery ventilation and uses a minimal space conditioning system.
- Solar gain is managed to exploit the sun’s energy for heating purposes and to minimize it in cooling seasons.
- Superinsulation and airtight construction provides unmatched comfort and even in extreme conditions.
- Continuous mechanical ventilation of fresh filtered air assures superb air quality.
- A comprehensive systems approach to modeling, design and construction produces extremely resilient buildings.
- Passive building is the best path to Net Zero and Net Positive buildings because it minimizes the load that renewables are required to provide.