Gathering ideas for the remodel was fun. I had been clipping out magazine pages, taking photos and writing notes during home tours, bookmarking web pages that conjured the feeling of “clean and beautiful,” learning from the mistakes of others, visiting showrooms, reading articles written by home energy professionals, attending conferences and workshops, and more. Choosing which of the numerous wonderful ideas to put into practice was much harder than I thought. Before our architect and Passive House consultant, Graham Irwin, could create the drawings and specifications, we had to tell him about our goals, what problems we’re trying to solve, and how we envisioned our daily life would flow in the house. Most of the cool ideas I’ve gathered didn’t make make the cut. In reality, we can only use one kitchen cabinet design even if I had clipped out five different styles I liked.
We appreciated the Passive House Standard. It is a performance-based standard that doesn’t dictate the look and feel of the house. When her transformation is done, Midori will look like a beautiful classic old house, allow us to flow through our daily activities with ease, and perform at the level of world-class energy efficiency. In chapter 5 of the Midori Haus book, we begin the design.
What I didn’t see at that time was the implicit boundaries or constraints we had. These constraints guided us down a path of seeing creative opportunities rather than picking out and settling for a collection of routine rule of thumb choices. Unlike the blank slate we had at the beginning of our real estate search, we were proceeding down a funnel of constraints to shape Midori to our intentions in the design phase. In Midori’s transformation design, we focused within the multi-faceted constraints by:
• Honoring the original Arts and Crafts style
• Observing regulations
• Heeding data from health and safety diagnostics
• Using space well to meet the lifestyle we envisioned
• Embodying our personal values
• Navigating kitchen design to solve problems
• Applying the principles of Integrated Design
• Ensuring we could afford the vision with detailed estimate.
We clarified our lifestyle we envisioned by walking through the house, room by room, and making notes on what was important to us.
We started out at the front door on Midori’s generous porch facing the street. This could hold a dozen people lounging around with a glass of beer or their favorite drink in hand, engaging in conversation. We liked our vision of porch parties and decided to keep the solid concrete porch as it was, maybe with new patio furniture to make the space more inviting.
When Kurt and I walked into the formal dining room to consider our lifestyle and what we would do there, we both looked at the built-in furniture and said, “That stays!” The built-in furniture defines the space. It would be perfect for displaying the collectible porcelain that had been cooped up in storage.
It was helpful to do this exercise for all of the rooms and things easily fell into place. The kitchen was a different story. No matter how many ideas Kurt and I batted around, it never felt right. That’s where a skilled architect shined by presenting us with a kitchen design that met our needs and wants.
We learned about integrated design, a process where the architect incorporated feedback from a contractor and consultants. I’ve heard of sad stories of homeowners who had worked with an architect to create a beautiful design and were ready to start construction with a permit in hand, but the bids that came back from contractors were way over budget for them. We wanted to make sure our design was within our budget and didn’t present construction problems for the builder. During the design phase, we hired Taylor Darling of Santa Cruz Green Builders as a consultant to provide contractor’s perspective.
I could see their complementary styles with a common passion toward green building working out nicely. Graham would send Taylor links to Passive House articles like the “Cost Effective Passive House as European Standard” or an article on method to fasten furring strings to sheathing through foam insulation. Taylor would suggest things from his experience like having the deck height be a half inch lower than the finished floor height to ensure a smooth transition and avoid a tripping hazard. When we considered whether to raise the roof height of the 1947 addition (master bathroom and closet) to match the main house, Taylor took measurements and answered Graham’s question of whether the existing structure had adequate space for insulation. Ultimately the decision was ours to raise the roofline or not. We didn’t. Observing the objective discussion between two professionals informed our decision.
Of all the different interpersonal interactions that took place during the project, there is none more important than the relationship between Kurt and me, the homeowners.
Midori gave us the opportunity to learn about each other. We’d been married for almost ten years when we started this project, but we’d never worked together professionally. We have different strengths, weaknesses, and working styles. We wondered if we would annoy each other. So far, our complementary skills have fallen into place. We gained appreciation and respect for each other as we navigated through the design phase.
If you’re wondering about what choices we made in our design, stay tuned. In the next chapter of the Midori Haus book, we get into the materials we specified for our design.
Passive House consultant Bronwyn Barry has noted that “passive house is a team sport” of architects, engineers, and consultants. At the beginning of Chapter 4 in the Midori Haus book we knew we needed a team of people, but we didn’t know how to choose them, how long it would take, or how much it would cost. We asked a lot of questions to reduce uncertainty and gain confidence in choosing team members. The most important questions, however, were directed at ourselves.
Q: Is this your forever house?
Q: What are you goals and priorities?
A: 1) Very green remodel focused on energy efficiency with Passive House; 2) Honor the look and feel of classic Arts and Crafts style; 3) Keep cost within our budget.
Q: What are you willing to do and what skills do you have?
A: See excerpt from Midori Haus book below.
We could have gone with a design-build firm and left it up to them to pick the people from their network. This choice makes the design-build firm the single point of contact accountable for the results. While it means paying more for project management services, we would only have one neck to choke if something went wrong. Had we been short on time due to demanding careers while raising a family, this approach would have been very attractive. Or if we had the hard core do-it-yourself streak in us, then we could have gone down the owner-builder route and become our own general contractor and done everything ourselves.
We happen to fall in the middle of this spectrum. We knew our own strengths and limitations. We would actually be miserable swinging hammers and using power tools. We have neither the talent nor the experience, so we’d make unnecessary mistakes and it would take longer and the outcome would be questionable. On the other hand, we are quite good at doing research and asking questions. We knew that we could apply our respective career experiences in hiring people, team building, and managing projects to our home-building project.
When we met with architects and contractors, we asked questions from a list we had prepared to see if we wanted to hire them. Their responses, and more importantly how we felt during the conversation, answered the main questions we asked ourselves: “Is he or she a good fit with our goals and priorities?” and “Is the chemistry right?” After all, we know there will be problems and challenges during the project. When it happens, we wanted to be partnered with someone who could rationally solve a problem rather than increase our stress.
Some of the most useful conversations took place with homeowners who were the reference clients of the architects and builders.
The best person to give information about the performance of a house is the person who lives in it. We found homeowners to be more than willing to share their experience and lessons from their house projects. They understood the value of the reference visit. The homeowners we visited were the beneficiaries of helpful others in their journey. They were now paying it forward by sharing their experience to those of us who were starting the renovation journey.
As with the architect interviews, we went in with a list of prepared questions. Our intent with the homeowner interviews was to build rapport with the homeowners in the first few minutes so that they would volunteer information as if they were talking to a friend. This was the closest we would get to test driving the construction experience, and we wanted to know what it really was like. We wanted to be exposed to things we hadn’t thought about. We weren’t trying to ferret out dirt about the builder or the architect, but we wanted to know what “gotchas” were lurking around the corner in a recent construction project and maybe avoid making that mistake.
Building rapport is key to shifting the homeowner from the place of representing the work of a certain builder or architect to helping a fellow homeowner by sharing their lessons learned. Before getting into the “Where did you get those lovely tiles?” types of questions, I like to find out the context behind the remodel to understand why they did the remodel in the first place. I can easily judge a house or a feature based on assumptions in my head, but my interpretation could be completely off base. Plus, asking questions like, “What problems were you trying to solve?” or “What drove you to do the remodel?” opens the conversation in a way that allows the homeowner to tell their story. After asking such questions, we we practiced active listening and then asked clarifying questions.
We talked to many people: architects, builders, and homeowners. We gathered information on products and materials used in their projects. We also gathered information on the process they went through and the lessons learned. After a while, I ended up with more ideas than we could practically implement. At these moments, it is just as important to release a dissonant idea as it is to embrace a brilliant one.
While interviewing architects and builders, we tested some of our pet ideas. We soon learned that a brilliant feature we saw at someone else’s house could not be incorporated into Midori out of context. It is just as important to release a dissonant feature as it is to embrace an unfamiliar logical concept. We needed to do both to move forward. So we thanked the architects and builders for the interesting exploration and moved on.
An example of a dissonant feature we released was a Trombe wall we saw at a friend’s house. It’s a passive solar design feature that uses an internal wall (our friend used brick) to collect heat from the sun during the winter day to release them into the living space at night. Several people coaxed us out of this idea saying it wouldn't work well in our coastal marine climate. We're glad they did because it would have been aesthetically awkward and it would have been expensive to beef up the foundation and floor to support the extra weight.
In a previous post, I mentioned the importance of asking questions and shared our list of questions we asked architects, builders, and homeowners. You’ll find the same set of questions at the end of chapter 4 in the Midori Haus book.
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.
The stories I’ve written in the Midori Haus book chronicles dual transformation: one of the physical building and another of the mindset of the homeowners. In chapter 2, you'll get the feel of homeowner mindset transformation. Excerpts below illustrate two shifts that took place before we even started the design phase.
In 2009, we lived in a condominium. It offered limited ability to make changes to the building to increase our standard of living and lower our carbon footprint. Initially, we thought creating a green, sustainable home meant building a new house from scratch. There was an implicit assumption of green buildings being new and good. Over time, we shifted toward remodeling an old building . This was our first mindset transformation.
… the inventory of unbuilt lots in a walkable area was quite limited and it was just a matter of time before we shifted gears to looking at houses in the right location that could be remodeled. In a way that’s more green than building a brand new house because remodeling reuses existing materials. For example, the utility connections are all in place. These connection costs are not trivial. In our area, it costs over $11,000 to install water service at a new house built on a vacant lot. Charges for the water meter and inspection are extra. Then there is the labor and material cost to trench and install the pipes and fittings, which may be another $10,000 depending on the distance between the house and the water main. That’s just for water. Sewer, gas, and electricity each have their own connection fees and construction fees. So there are some savings from having existing infrastructure connections despite paying a slightly higher price for having a house on the lot.
Another transformation took place slowly, as we learned about due diligence before real estate purchase. We were quite naïve in 2004 when we were planning to buy some land to build on.
… buying so much land so close to downtown Santa Cruz for a price of a small house seemed like a dream. Back then we were rather naïve. Instead of doing due diligence with a soils report or researching zoning to see if the lot was buildable, we did silly things like driving out there late at night and sitting on a log to see if we would see the ghost lady that supposedly haunted the area. Getting caught up in Karsten’s enthusiasm, we were convinced that we could do this project fast and cheap. Because we didn’t know what we didn’t know, we floated in a nice dream for a while. It was a perfect escape from the daily grind of managing projects and people.
Our real estate education was greatly aided by a mentor. Gary Ransone’s unique combination of qualifications (real estate license, general contractor’s license, and construction attorney license) guided us to perform sophisticated due diligence.
… Gary went over and beyond what a typical real estate would do and visited the building department at the City of Santa Cruz to look up building permit records to see if the small addition containing a bathroom and a kitchenette was legit or not. This was a precautionary step to see if we would run into permitting issues when we submitted our plans for the remodel.
… Gary wanted us to have the property boundaries confirmed and have the records “clean” by confirming the mutual easement on the property boundary. This was prompted by the presence of a duplex garage and a shared driveway with the neighbor to the west.
You'll see a summary of lessons learned at the end of each chapter. One lesson I’ve often passed on to others is to have a general contractor look over the house before making an offer buy the house.
I would love to hear what you found useful in chapter 2 of Midori Haus book. Please let me know by commenting below. Thanks!
In November 2017, you’ll be able to hold a copy of my book in your hands and enjoy the vicarious experience of transforming an old house. The book is titled, Midori Haus: Transformation from Old House to Green Future with Passive House. Published by Hybrid Global Publishing, it is available in both paperback and e-book.
It’s a story of an ordinary house having extraordinary results using materials available in the market today. If you have aspirations of making your house green and sustainable, you’ll enjoy this case study told through the lens of a homeowner. It’s written in a conversational way as if you’re listening to a friend over a cup of tea. For example, in chapter 4 you’ll find the answers to the question, “What questions did you ask when choosing your architect?”
If you’re wondering about how to apply your collection of notes, neat ideas, and file full of green products brochures, you just may find yourself in chapter 3. At that point we were running the risk of creating a house with a hodgepodge of green ideas that may not have worked well together. Fortunately, we found a very good international building standard that looked at the building as a whole. Using the energy efficiency focus as the core of our project, we managed to avoid the green hodgepodge.
Did we do everything right? No. At one point we naively thought that we would arrive at a single logical solution if we spoke to enough experts to solve a problem. That was not the case. We stopped construction for months while we wrestled with this issue in chapter 13. We learned the hard lesson—when expert opinions diverge, it’s up to the homeowners (who hold the purse string and who will literally live with the decision) to choose the path.
I wrote this book for you. It’s for those of you who want to live in a healthy, comfortable, green home and are gathering ideas for your project. It’s also for architects and contractors who want to share the Passive House standard with their clients.
Thank you for reading this post.
I feel good when I have more things in the blue recycling bin than in the brown garbage bin when I roll them out to the curbside. For many years my recycling knowledge and effort ended at the blue bin. That changed when I took a tour of the Recycling Center at the Resource Recovery Facility operated by the City of Santa Cruz. This is nestled in the Wilder Ranch State Park, a few miles west of where I live. The facility sits on a hill, about 300 feet above sea level, with almost a direct view of the 3-Mile Beach. They offer public tours periodically.
At the beginning of the tour I heard, “When in doubt, throw it out.” I was shocked. Still, by the end of the 90-minute tour, I understood why. Here are five things I learned from the Recycling Tour.
1. Plastic Bags
Some plastic bags are recyclable and some are not. So, how do I decide which one to recycle and which ones to toss into the trash? I’ve read the guidelines printed on the colorful flyers that arrive in the snail mail, but I could never remember all the rules and exceptions. “These plastic bags are recyclable,” said Leslie, our tour guide who works for the City of Santa Cruz, as she held up some used plastic bags. “These are stretchy and don’t make a lot of noise when you scrunch them.” Then she picked up a different bunch of used plastic bags and scrunched them and said, “These are not recyclable.” Sure enough, they were louder and stiffer with no stretch to them. That’s easy to remember! I can use the scrunch and stretch test from now on. I just need to remember the plastic bag protocol: place a bunch of the plastic bags in one bag and tie them.
Soft and stretchy bags on the left are recyclable
Notice the bags within bags in the bales
2. Clamshell Food Containers
What surprised me was the next thing she picked up. A clear, clamshell plastic container that is ubiquitous in stores. “These are not recyclable,” she said and I gulped. I’ve always put those clear plastic containers used to hold strawberries, blueberries, and Persian cucumbers in the recycling bin. Those need to go into the trash bin. Ugh! I don’t think I will completely avoid buying them in the future, but I will definitely think about the trash impact before buying them. “It’s about making trade-offs in different areas of life,” said Leslie. We can choose to do better in one area and worse in another since we can’t be perfect all the time.
3. Limited Landfill
So what is recyclable and what’s not? As I looked around the room and noted informational posters, I realized that it’s not an arbitrary decision made by the city government. It has to do with what the market will buy. One ton of metal could be sold for about $1,700. The price of plastic fluctuates with the price of oil. If the price of oil is low then the manufacturer may choose to buy oil to create new plastic products, but if the price of oil is high buying recyclable plastics become attractive. So the demand for used plastic and the price of oil have an inverse relationship. Right now, one pound of rigid plastic (like plastic buckets and cheap lawn furniture) will fetch four-cents. Same with paper. One ton of used paper will be sold between $72 and $84 or $0.4 per pound. The sales price for used paper and plastic seem hardly worth the effort. But the reason to recycle is not financial. The motivation is driven by the need to divert waste from the landfill as this coastal landfill site has a limited capacity.
4. Manufacturing Enables Recycling
Recycle means to treat or process waste material so that the material can be useful again. Used glass bottles and jars are cleaned, crushed, and melted to create jars and bottles. Used aluminum cans are cleaned, melted, formed into large blocks, rolled out, and made into cans and other containers. Used paper is cleaned, pulped, de-inked, and made into another paper product. Used plastic have a more complex process and there are different types of plastic that are commonly recycled: (1) PET or PETE are used for soft drinks, water, peanut butter jars; (2) HDPE is used for milk jugs and trash bags; (3) PVC is used for piping; (4) LDPE is used for frozen food bags and flexible container lids.
Another way to look at recycling is the willingness and ability of manufacturers to take consumer waste into their manufacturing process. To make this feasible, an infrastructure to collect, sort, and market recyclable waste must be in place. What makes recycling work in my city is the presence of facilities in the Bay Area that use these materials to make their products, and that there is demand for them (such as bottles used by wineries in Northern California). I realized that this infrastructure and end products determine what is accepted as recyclable material in our community. I’ve often wondered why some cities don't offer curbside recycling service, but now I see that collecting recyclables from the blue bins is just first step in the recycling process. Without the investment in sorting, transporting, processing infrastructure, and demand from manufacturers recycling is not feasible.
5. Avoid the Jam
What the Resource Recovery Facility does is the first step in the recycling process. The post-consumer recyclable materials are brought into the facility to be sorted and baled. The sorting machinery separates the metals, glass, plastic, and paper into different areas. Human intervention removes non-recyclable and contaminated items from the work stream. The conveyor belt moves fast. Trained eyes and split-second decision of the workers keep the flow moving. The better job we do in placing items in the blue recycling bin at home, the less intervention is needed at the recycling site.
Machinery jams every so often because of tangling items and small bits. There is nothing like seeing the line stop to sear an impression. I’ll make sure I won’t throw garden hose (tangling non-recyclable item) or tiny bottle caps (things that cause jamming) into the recycling bin. At the end of the tour, I appreciated the wisdom of the phrase, “When in doubt, throw it out.”
Garden hoses (tangles) can cause problems
Let's Be a Conscious Consumer
If I look upstream from the activities at the Resource Recovery Facility, I see opportunities for making a difference. If I have a mixed material item like the can of coffee beans from Trader Joe’s, I can choose to separate the metal from paper and put it in the blue recycling bin or throw the entire can in the trash. Better yet, I can choose to buy coffee in bulk at the grocery store and avoid deconstructing the coffee packaging. Bringing my own jar and re-using it continuously avoids recycling the coffee packaging all together!
We can choose to be a conscious consumer when an opportunity presents itself. Maybe not buying something impulsively (like a cool kitchen gadget or yet another intriguing book) is another opportunity to be a conscious consumer. How would you make your personal trade-off decisions to be a conscious consumer?
Coffee can in its entirety is not recyclable
Separate paper and metal to recycle
Have you asked yourself, “What do I want to get out of this home tour?” or “What do I want to get out of this meeting with a contractor my friend recommended?” or “What should I ask this homeowner who is a reference from this contractor I’m checking out?” Preparing a list of questions ahead of time will make the visit or meeting more productive, especially if there is a decision to make afterward. I found it easier to adapt from someone else’s list, so let me share my list of questions with you.
You can find the list of questions we asked homeowners during the reference visits or reference calls attached here. Next to each question, I’ve listed the reason why we asked that question as well as follow-up probing questions. Keep in mind that homeowners who recently completed their project will have the cost and project experience fresh in their mind. The homeowners who have been living in their renovated house will have rich experience of how the material, appliance, or products have held up over time. You can use these questions or adapt them to your situation.
The list of questions we asked architects and contractors during the interview process is attached here. Next to each question, I’ve listed the reason why we asked that question as well as follow-up probing questions. You can use these questions or adapt them to your situation.
The list of questions linked from paragraphs above can be found at the end of Chapter 4 in the Midori Haus book. Here is a short excerpt from that chapter.
Some of the questions we crafted in the behavioral interview style would give us a feel for what it would be like working with them. For example, by asking, “Could you give us an example of a problem that came up in your project and how it got resolved?” we gave them a chance to tell a story to illustrate their problem-solving skills. Their answers would give us a sense of their problem-solving style as well as how they’d likely behave under pressure. Everyone is on good behavior during the interview. But when there are problems and things are stressful, we wanted to be partnered with someone who could rationally solve a problem rather than increase our stress. One of the builders we interviewed emphatically said that he would never work with a certain architect again. We asked him why.
“Because the last time I worked with him he lost it when we ran into a problem. He swore and berated me in front of others. It’s not professional.” Good to know. We didn’t have that architect on our list and after that discussion, we wouldn’t be talking to him for sure.
That conversation gave birth to one of my favorite questions, “What types of projects have you turned down or refused to do?” Most people pause and give a thoughtful response. The answer provides us with an insight into their boundaries and their personal standard of integrity.
When you visit a home, don't forget to note what your skin, nose, and eyes are sensing. It's one thing to have data from gadgets (temperature, humidity, air movement, air quality, sound, smell), but nothing can replace what your body is telling you.
Below are some insightful questions we’ve been asked while giving public tours of our house. I wish I thought of these! Share the useful question you’ve used in the comment below, if you’d like.
Several times a year, we host a tour of Midori Haus to share our knowledge and experience of remodeling an old house to be green (healthy, energy efficient, water efficient, and sustainable). We delight in explaining what Passive House is and showing how features of Midori Haus reflected Passive House principles. At the last tour, we were pleasantly surprised to learn about a cooking method that embodies Passive House principles: energy efficient cooking within airtight vessel with good insulation.
One of the visitors brought along a thermal cooker. This is an efficient appliance that uses very little energy and effort. The food is cooked in a thermal cooker pot on a stovetop (gas, electric, or induction) and brought to boil for about 10 minutes. Then this pot is inserted into a thermos-like enclosure that cooks the food with residual heat.
Brilliant, isn’t it?
I used to think slow cookers or crockpots were pretty energy efficient. Now, I can see that slow cookers are like coffee makers (coffee stays warm by sipping electricity) and thermal cookers are like a thermos (coffee stays warm for a long time without electricity). When the hot food is placed in the well-insulated airtight enclosure it only loses heat at the rate of 4 ~ 5 degrees Fahrenheit per hour. If the temperature of food in the inner pot is 200 degrees when it’s taken off the stovetop and placed into the outer container, eight hours later it would be about 160 degrees, still plenty hot. Because there is no additional heat applied to the cooker, it won’t burn. I find this feature attractive since I’ve burned edges of stews in my slow cooker.
History and Food for Thought
The principle of thermal cooking has been around for a long time. I invite you to read this article from Low Tech Magazine, "If We Insulate Our Houses, Why Not Our Cooking Pots? " It explains why cooking is so inefficient and covers the history of fireless cooking with striking images. If you prefer to watch a short video instead of reading about low energy cooking history, then take a look this video titled, “A Bit of History About Thermal Cooking.”
Our visitor recommended the Tiger brand of thermal cooker, which she brought. I placed the inner pot onto my induction cooktop to see if it was compatible with induction. It was. What else shall I consider before buying one? Performance (keeping food hot longer), durability (quality materials and good construction), and cost are what I typically look for, but these two videos gave me further insight:
Ecopot Thermal Cooker Comparison video advises to look at these characteristics:
· Pot’s locking mechanism
· Food cooking capacity
· Quality of inner pot
· Heat retention technology
· Technology used to avoid aroma bypass
· Ability to reheat food to 70C (above food safety standard of 60C)
Cindy Miller, author of Let's Make Sense of Thermal Cooking Cookbook, advises people to choose models that retain heat for 4 – 8 hours. The insulation type and capacity is explained in a show and tell fashion in this Types of Thermal Cooker video.
I’ve heard that many recipes can be adapted for the thermal cooker. Perhaps I’ll try some of these recipes from Delishably when I get one.
Last month, I spoke at the KMH Women’s group event in Honolulu. Knowing that Hawaii imports fossil fuels to generate most of the electricity in the state, I wanted to share as much energy savings tips with the audience. I did a simple experiment to convey why induction cooktop made sense for the people in Hawaii to make it relatable and interesting to those who want to do the right thing for their family and home.
Armed with measuring cups, kitchen thermometer, and a stopwatch, I measured how long it took to boil two cups of water in a kettle. First, I did this in my home in Santa Cruz California on an induction cooktop. It took 2 minutes and 56 seconds. The air temperature in front of the kettle went up by 1.1 degrees, from 71.6 degrees Fahrenheit to 72.7.
Time to boil water
Then I did the same thing at my dad’s place in Honolulu Hawaii on an electric resistance cooktop. It took 6 minutes and 23 seconds. It took more than twice as long! The air temperature in front of the kettle went up by 1.3 degrees, from 77.4 degrees Fahrenheit to 78.7. Since this was in the cooler month of January, the increase in temperature wasn’t uncomfortable. Had this been done in August, I would have broken a sweat because my dad’s place doesn't have air conditioning. In homes that do have air conditioning, cooking during the summer on an electric resistance cooktop would make the air conditioner work even harder to counteract the heat.
Time to boil water
This experiment affirmed my conviction that an induction cooktop is better than an electric resistance cooktop, especially in Hawaii where the electricity rate is more than twice that of California. We can save time and energy. We can avoid extra heat in our kitchens. So, if your kitchen stove is at the end of its life and needs to be replaced, look into induction cooktop.
Before you run out and buy one, check to see if there is adequate capacity in the wiring and electrical service to your house to install the induction cooktop model of choice. I invite you to read this article from The Induction Site to get the details.
When you start shopping for induction cooktop, the price tag might scare you. Especially if your point of reference is electric resistance free standing stove that is about $1,500 cheaper than induction. It seems expensive, right? Before you turn away, I invite you to consider the lifecycle cost. Since the savings come from the on-going electricity savings, let’s look at how much energy savings would make this higher initial cost worthwhile.
1. Appliances last about 10 years, so when we spread out the higher cost of induction ($1,500), it comes out to be $150 per year or $12.50 per month.
2. Average price of electricity on Oahu is $.28 per kilowatt-hour (kWh). Dividing the $12.50 per month by the average price of electricity, this comes out to 45 kWh.
3. Say your average electricity usage per month is 350 kWh, the 45kWh target savings represents 13% of the monthly bill. On average, appliances use 28% of electricity in homes, so 13% seems feasible.
One thing that people fuss over when making a decision to go with induction cooktop is the cost of replacing the pots and pans. Once again, I invite you to read the cookware article from The Induction Site to get expert tips on why you may need a different cookware and how to shop for new cookware. I didn't spend a fortune on new pots and pans. In my case, I kept my cast iron skillets and only bought a couple of sauce pans.
Bottom line, switching from electric resistance cooktop to induction cooktop makes sense, especially in a climate that uses air conditioning. To move forward with confidence, be sure to research the electrical requirements of installing an induction cooktop, calculate the cost savings, and check your pots and pans.
On November 18, 2016 we did some maintenance. The Zehnder ComfoAir 350 ventilation system is the heart of our Passive House (Passivhaus in German). It continuously provides pre-warmed filtered fresh air to different rooms and exhausts stale air from kitchen and bathrooms. The heat recovery ventilator (HRV) was originally installed four years ago and commissioned in January 2013. In addition to cleaning out the filters couple of times a year, we were supposed to clean out the HRV core annually. This was the first time we pulled out our HRV core and it was quite dirty.
We also pulled out the bypass duct. Our system is configured as ComfoAir 350 LEFT where the fan on the right side move the air in and out of the house (through ComfoPipes) and the fan on the left move the air within the house (through ComfoDucts.) In the LEFT version the bypass duct (black hexagonal foam) is installed behind the core.
The body of the ComfoAir 350, the casing that housed the core, was dirty too. Our first task was to clean out the dust, dirt, and dead bugs. We didn't have a vacuum cleaner handy, so we simply wiped down the surface with damp paper towels.
There are two fans: one of the right and another on the left. We pulled out the fan on the right side, opened it up, cleaned it, and replaced it. Then repeated the procedure with the left. We took care to not pull on the power cables attached to the fan.
Now that everything is clean again, it's time to replace the core. Instead of re-installing the HRV core we chose to install the ERV core (enthalpy exchanger). Note that the ERV core is blue. The color of the HRV core was teal. This will help redistribute the moisture extracted from the kitchen and bathrooms to the other rooms. We are doing this because we live in a dry climate. In the winter the air outside is so dry. When the dry air is brought into the house the relative humidity in some of the rooms drop below 30 percent. So, to avoid dry skin and chapped lips, we are doing an experiment this winter.
We will be collecting the temperature and humidity data through our WELserver. While our sophisticated body sensors (skin and lungs) will tell us whether our experiment was a success or not, the measurements of relative humidity will convey them in numbers. Stay tuned.