Chapter 3: Setting A Building Energy Limit

December 22, 2017

We couldn’t look at houses the same way again after we learned about the internationally recognized performance-based energy standard in construction called Passive House (Passivhaus in German). In chapter 3 of the Midori Haus book you’ll read about another shift that happened to us. My mindset transformed from “looking for a tech gadget that made green magic happen at the push of a button” to “looking at the whole house as a system and appreciating good design and craftsmanship.”

Early on we thought green building consisted of different green components: something that used resources efficiently so that we didn’t end up consuming everything and leaving nothing for future generations; something that protected our health so that we didn’t get sick from breathing toxins or allergens; something that reduced waste and pollution so that future generations (and ours) could enjoy clean air, clean water, and nature.

I used to think, “Why not install photovoltaic (PV) panels on the roof to generate electricity from the sun and be done with it?” Solar energy is green, right? We could generate all the electricity we used in our home and sell some back to the utility so that at the end of the year our electricity bill would be near zero. It would probably pay back in about twelve years. I wondered why some­one would go through the extensive calculation and install lots of insulations and perform extensive air sealing to save energy. It seemed to me that PV was easier and better. Eventually we learned that it depends on how you frame the problem.

The problem we were trying to solve was not solely about getting the electricity bill to zero. We wanted to live in a house that was comfortable and healthy. Covering the roof area of a ninety-year-old house with PV would not make it comfortable and healthy.

We first heard about the Passive House Standard in March 2010. We didn’t fully embrace it when we first heard about it from a green building consultant who came out to give advice on a property we wanted to buy.

On the surface there was nothing profound in what he had to say—better windows, insulation, minimizing air leaks, consider the shading from the trees. These all sounded mundane and pedestrian, perhaps because I was secretly hoping to get an insight into the latest tech gadget that makes green magic happen at the push of the button. Sadly, he offered no such gadget. The one thing that seemed to perk him up was discussing the Passive House Standard.

We didn’t dive into Passive House after our initial encounter with the consultant. Six months later, we were in a Passive House workshop. That’s when we finally embraced Passive House.

Chie and Kurt, ordinary homeowners, transformed into Passive House enthusiasts with a single realization: energy used to quickly adjust temperature, either to heat or cool a conventionally built house, can be eliminated if the shell of the building is constructed like a thermos. Keeping the indoor temperature constant and controlling ventilation could make our house comfortable and healthy. And we didn’t have to wait for some new invention to come about or spend extraordinary amounts of money to achieve a radical reduction in home energy.

The tools, techniques, and products to successfully build Passive Houses are available today. It requires the architect to use detailed modeling to guide the plans to hit the specific target for energy use. It requires the builder to pay careful attention to construction details and comply with the specific limit on air leakage. In other words, good design and good craftsmanship. This is Passive House.

Kurt summed up the appeal of Passive House Standard by saying, “It’s brilliant systems-thinking.”

… The green buiding certification programs we’d seen so far were like ordering à la carte from a restaurant menu: slap on a solar panel, get energy star appliances, get bigger windows to make use of day lighting, and so forth. Each component was green in its own way, but who knew if they would work together effectively to seriously reduce energy consumption. I didn’t want to wait until after we lived in our house to find out if the mishmash of systems resulted in comfort or heartburn. The Passive House Standard was geared towards achieving a very specific low-energy use with occupant comfort in mind…

We wanted more than a lower utility bill. Our focus was to follow our values and do the “right” things that would last a long time. We wanted to use more current sunlight and less of the ancient sunlight. We wanted the air inside our house to be healthy. We wanted the house to be pretty and pleasant and we wanted to be comfortable living there. We wanted to demonstrate and show others that an old house can retain its charm and have excellent energy performance. We wanted everything to work together nicely and within our budget. Passive House represented the path to achieving this. Simply install a bunch of PV panels on the roof without dong any of the other work did not.

It’s not that we’re opposed to using PV. Learning about Passive House clarified the sequence for us: First, do the improvement on the building envelope. See how it performs. Then later add PV when we’re ready to switch from gasoline vehicles to electric cars.

In the introduction of this book, I said that the most important thing we learned was to stick to our personal values, and that has guided us through buying a home and navigating options to make it green. Besides the personal benefits we’d enjoy by living in a Passive House, we set about on this renovation project to make a contribution to the greater community. Rather than wait for the government to institute regulations to curb greenhouse gas emissions to retard climate change, we wanted to reduce the greenhouse gas emissions that came from living in the house.

Learning about Passive House made a big difference in how we approached our home renovation project. Are you curious about the Passive House Standard? This short video will explain it in 90 seconds.

About the Author

Chie Kawahara

Chie is one of the co-creator of Midori Haus. When she is not sharing her stories of transforming an old house and giving tours, she enjoys trail running and hiking.

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