Plans Submitted

This morning we submitted our plans at the City of Santa Cruz Building Department.  5 sets of plans along with energy calculations and archaeological reports were submitted.  The archaeological report was needed because the house sits in a zone that is archaeologically sensitive.  Fortunately the archaeology found nothing interesting.  The city’s green building program require plans to have the green building checklist as part of the plan.  The checklist is used to tally the green points.  There is a minimum number of points required for the permit to be issued — 20 points for new construction and 15 points for remodel.  If the total number of points on the plan is above 45 for new construction or 35 for remodel the plan is eligible for accelerated building permit processing.  If you rack up more than 75 for new construction or 45 for remodel then you receive the green building award and move up to the front of the queue.  Our plan easily exceeded the number of points for green building award so we expect the processing to move along quickly.  By the way, when we spoke with the city’s green building specialist a year ago, he mentioned that about 30% of the permits received green building award.

So, what’s in the plan?  Well, the size of the living space remains at 1569 sq.ft. and the roof has about 10-15 years of life so we are not changing that.  Just about everything else will be touched. These include –

  • Replace all windows (single pane to triple pane)
  • Replace all existing exterior doors and add french door to the master bedroom
  • Expand the kitchen area and lay it out to accommodate 2 cooks in the kitchen
  • New kitchen cabinets
  • All new energy efficient appliances
  • Replace all plumbing fixtures
  • Replace all lighting fixtures
  • Rewire the entire house
  • Re-plumb the entire house
  • Refinish the hardwood floor where possible
  • Remove all existing floor covering and either refinish hardwood floor or put new covering
  • Insulate walls, ceiling and floor
  • Remove siding and replace with Hardie planks
  • Remove floor furnace
  • Install Heat Recovery Ventilator
  • Plumbing to make it gray water ready  
  • Most challenging part will be to make it air tight to meet Passiv Haus standard

It’s taken us a while to get to this stage because we did a lot of research and education in this past year to get educated on various things and shopped for appliances, fixtures, insulation, door, windows, sidings, etc.  So we pretty much know what we want and what we don’t want.  We’ve kept a list of materials we’ve selected on a spreadsheet in Google Docs so that we can share it with the other people we’re working with.

Now we will turn our attention towards getting bids from general contractors.

About a year ago is when we first saw the house for sale.  We thought we’d move along quickly through the design process but it took much longer than we originally anticipated.  Now, if we can just begin construction by the anniversary of our escrow close on September 17th, we’ll be pleased.

Crawling Around Crawlspace

I can’t believe I managed to crawl around under the house today!  You see, I don’t do well with creepy crawly creatures and I usually scream upon reptile sighting, even at a distance.  Fortunately, I did not see anything today that got my heart racing.  Phew….

Since I don’t have one of those jumper suits for crawling around dirty spaces I wore my mud-stained hiking clothes and made sure that my 20″ hair was tucked nicely inside the shirt.  I put an old baseball cap on my head, backwards, and strapped on my halogen headlamp.  With a camera in my hand, I stuck my head into the opening on the south end of the house.  The opening is certainly big enough for an adult male to crawl through so I had no problems getting in and maneuvering around.  Once I got over the large pipes I found that I could actually crawl on all fours instead of slithering around.  The clay soil was slightly moist but not wet.  I took pictures — first west, north and east walls then I crawled towards the center of the house where remains of a brick fireplace was under the kitchen.

There are 4 columns of 10 posts running north-south direction.  I saw knob and tube wiring, old floor furnace and galvanized steel piping.  These are all the stuff we saw on the home inspection report when we bought the house and intended to replace them so it wasn’t surprising.

Here are some pictures under the house:

Water wicking up from the soil through concrete to wood

Remnants of chimney

Old pipes

Knob and tube wiring

Indoor Air Quality – Testing For Radon

Radon was one of the topics covered in the Indoor Air Quality class we took recently.  We understand that the concentration of radon gasses that naturally come out from the soil various from region to region and in some cases from house to house.  Our instructor, Rich Prill, Washington State University’s Extension Energy Program, mentioned that one of his clients found higher level of radon compared to the neighbor’s houses because there is a subterranean stream running under the client’s house some 10-20 feet below surface that affects the gas composition of the soil under the house.  So, even if the radon zone map of California show that we are in a moderate area (predicted average indoor radon screening level between 2 and 4 pCi/L), we should test for it.

What is radon?  
Radon is a noble gas that doesn’t react with anything else.  It’s present in our soils, rocks and sometimes water.  The problem with radon is that it has a 3.8 day half life during which it goes through radio active decay, releasing alpha particles that can cause lung damage.  So, if you breathe in radon, which is a colorless and odorless gas, these large alpha particles can damage and mutate cells in lining of your lungs.  Radon is the second leading cause of lung cancer after smoking.

So where does it come from?  You’ve heard of uranium, right?  Uranium 238 is the most prevalent naturally occurring radioactive material in the ground.  It has a half life of 4,500,000,000 years.  Uranium 238 eventually turns into radium 226, which has a half life of 1590 years.  Then radium 226 turns into radon, which has a half life of 3.8 days. At this  point you may ask, “What is half life?”  Half life means the period of time after which only half the mass of the original radioactive element remains.  So, suppose a radioactive material starts with 100% of a radioactive material, after a single span of its half-life only 50% of that radioactive material would remain. The other 50% of the material would have converted either into energy or another element which may or may not be radioactive.

Why do you want to test for it?
Radon is a colorless, odorless gas and it occurs naturally and it’s in our soil at different concentration.  The gas comes out of the ground and it can get into your house if the floor is not airtight.  Most houses with crawl space like ours is not airtight.  We know it’s not airtight because we can smell the dampness and mold from the crawl space when it rains.  So, if there is any radon in the ground, it would certainly get into the house.  In fact, when it rains the water in the ground acts like a air and vapor barrier so any radon gasses in the ground would look for path of least resistance, or dry soil to release.  The dry area happens to be under the house so when it rains the crawl space may have extra concentration of radon.

The testing result could be different from day to day, depending on the season, rain and stack effect.

EPA gathers data from the various testing conducted by labs and publishes results (aggregated by zip codes) on a map.  California Department of Health publishes a report that lists the number of tests conducted in a given zipcode as well as the number of tests that resulted in level above the EPA threshold of 4pCi/L.  You can find the PDF here.

A reader of this blog suggested this resource for radon detection and safety.

Next Steps
So, I just bought some short term radon test kits at the neighborhood hardware store and will test the house.  If the results show a level higher than 4pCi/L then we would take measures to mitigate it by putting in a pipe under the plastic sheet used for sealing off the crawl space and venting it to the outside.  You can find a PDF of radon resistant construction here.

UPDATE:  Our result for the short term (96-hour) Radon test was .2pCi/L, which is quite low!

Passive House Tours

Organized home tours are great way to get ideas, meet interesting people and learn about the house.  Architecture and landscaping gives a certain “feel” to the house.  Finding out about material choices give an insight to the owner’s values.  Learning about various systems used, like solar thermal, photovoltaic, energy management, rainwater harvesting and gray water systems has been interesting and often inspiring.  Years ago, when we’ve attended “Solar Homes Tour,” or “Green Homes Tour,” or “Open Architecture Tour,” we would dream about doing a green house project of our own someday.  After visiting a home we would note, “How we felt,” at the house and discuss what we liked and disliked about the house.  These tours were planting seeds in our mind.  After going to so many of these we found that our tastes and preferences were similar so when we decided to do our Midorihaus Project we simply germinated the seeds that were planted through the tours.

This year we’ve been to several “Passive House Tours” in the Bay Area.  Unlike the one day organized tours of several houses where people come and go all throughout the day, these Passive House Tours are compact and provide the visitors with an in depth view of the project.  At each of these sites there is a formal presentation with a team of architect, builder, passive house consultant and sometimes the owner that presented the highlights of the project.  They’re all quite passionate about building energy efficient homes and are generous with their time.  We’ve learned so much from talking to different people at these tours!

This is a brief list of passive house tours we’ve been to this year (2011).

March 27 – Cottle Zero Energy Home in San Jose, designed and built by One Sky Homes.

May 13 – Green Gulch Farm at San Francisco Zen Center at Muir Beach.

June 1 – Menlo Passive Project in Menlo Park by Clarum Homes.

Coming up….
Green Home Project in Palo Alto that is going live on June 4.  This site will host the next monthly meeting for Passive House California on June 26.

Of course, sometime in 2012, we will host a tour of our Midorihaus Project in Santa Cruz.

Our Energy Baseline

Because we chose not to live in the house until the renovation is done, we don’t have an exact way to measure the energy performance improvement from the renovation.  It would be fantastic if we could say, “Our annual energy consumption at the house was 100 before the renovation and and after the renovation it dropped to 20, so we realized 80% improvement.”  That would give us a nice clean comparison, but we don’t want to live in the house while construction is going on.  So, we will be using relevant data for this “before and after” comparison.  The former resident of the house, Bob, was kind enough to provide us with access to his past utility bill data.  This provides us with an approximate baseline of how much energy was used at the house “before” renovation.  Thanks Bob!

Along with the attribute of the house, the lifestyle of the occupant plays a role in the energy consumption — what kind of electronic gadgets used in the house, what’s the preferred thermostat setting, what kind and how much cooking is done, and so forth.  You may remember that we’ve been going to various energy efficiency classes and several of the instructors suggested we gather and analyze our utility bill.  So, I did just that last week for our current home.  Our current home is a 1,300 sq.ft., 3-bedroom, 2-bathroom, 2-story condominium where we share 2 walls with our neighbors.

First, I logged on to our home account on the website of our local utility, PG&E,  and gathered data from our past billing history.  The Excel spreadsheet with the basic data looks like this.

Next, I took the gas data and graphed it over a 12-month period.  This is useful because I can tell how much gas is used for heating the condo from the shape of the curve.  How?  In our mild climate we don’t need to heat the home during the summer months.  You’ll notice that the gas usage in the months of August, September and October is constant at 10 Therms per month.  Because we have gas furnace, gas water heater, gas oven, gas cooktop and gas clothes dryer, the 10 Therms per months represent our normal usage of hot water, cooking and clothes drying.  Anything above 10 Therms is for heating.  You can see the gas usage goes up in the winter and down in the summer, where in December we’ve used up to 35 Therms to heat the house.  Here’s what the graph looks like.

Then I graphed the data for electricity.  This turned out to be pretty uniform throughout the year.  In July we were on vacation so both gas and electricity usage dipped a bit.  There is a slight bump in electricity usage in December.  I’m guessing that  we used more lights around the winter solstice when days are very short.

Interesting, isn’t?  We can further analyze the electricity data by doing some detective work.  There is a little device called, “Kill A Watt,” which measures the electricity usage of an appliance by plugging in the Kill A Watt device into the electric outlet and the appliance you want to measure into the device.  A couple of years ago Kurt went around our home and measured different equipment and found that his stereo equipment had quite a bit of vampire load or standby load.  This means that the equipment uses electricity for just being plugged in, even if the equipment is not turned on.  He immediately put his stereo on a separate power strip and turns off the power strip when he’s not listening to music.

By the way, we got a bonus credit of 20% from PG&E in March for low energy usage. They sent us a lovely email expressing their appreciation for conserving gas.

I don’t think we were consciously trying to reduce energy consumption this winter, but we were curious. So we did a little experiment to find out, “How cold does it get in the house?” by turning down the thermostat to about 50 degrees Fahrenheit.  The answer?  In the range of 60-65 degrees Fahrenheit.  Actually, I’m glad that experiment is over…

What’s Important

Color Coded Diagram

A while ago we clarified our priorities by writing down what’s important to us for this Midori Haus project.  It was a good exercise for us even when we knew that our values are closely aligned.  This is what we did –

  • On a blank sheet of paper we wrote down words and phrases that answered the question, “What is important to you?”  This was done in a brainstorm fashion where we each grabbed a pen and wrote down thoughts as they came.
  • Next we reviewed the items and agreed that all of the items could fit into 5 categories.  The categories are, “Happiness,” “Our Values,” “Passive House,” “Initial Cost,” and”On-Going Cost.”  I’m sure if a dozen different couples did the same exercise there will be a dozen different ways of slicing and dicing their list.  These 5 categories just happened to be the ones that came together for us.   
  • Then we took different colored pens and circled the items on the list  Some of the items fell into more than one category.  It was interesting to note that some items had double or triple circles.  Here’s what that looked like:

  • We took one more step after the color coding step to prioritize the items in each category individually and compare them.  For the most part our priorities matched!

We did this exercise partly to have an agreed upon basis for making trade-off decisions as we move along in the project.  Most recent usage was to review and compare the cost estimate line items with our color coded priority to see where we could reduce cost.

Who’s Rules?

Back in January, we had an opportunity to visit with Larry Weingarten at the House on Hummingbird Hill.  He generously spent time with us and shared a lot of information about his home, his approach to building and the amazing hot water heater museum he has in his basement.  His house was very comfortable and I was amazed at how he could heat the house to a comfortable 70 degrees (F) using solar heated water at only 80 degrees (F).  There are many interesting features to his home and I invite you to explore them at the Water Heater Rescue site.

When we showed our exuberance on passive house, he asked a very sage question, “Who’s rules are you following?”  Then kindly suggested that we spend money on “What we want,” and “Not necessarily to a standard.”  He made us think whether we fell into the lure of “Getting a certificate or plaque on the wall for bragging rights,” like some do with LEED, Greenpoint rated, Passiv Haus, Net Zero Energy, etc.  He was trying to make sure that we’ll be happy at the end of our project.  One of the design rule Larry used was, “What will last 200 years?” He was also very focused on “quiet” in his home.  His refrigerator was so silent that I didn’t know it existed.  Well, I think he planted a seed during that conversation because it led us to doing the color-coded diagram above.

Invest in Items With Long Life

Sometime last year I spoke with a local builder who was born in Germany in a house that is more than 600 years old.  Wow, talk about a building with long life!  I wondered if our building stock in our neighborhood, city, country would last that long.  Probably not.  If you’re interested in ideas on making buildings more sustainable and increase longevity, have a look at Tedd Benson’s lecture at the College of the Atlantic.  I like the idea of applying the concept of Product Lifecycle Management and building as a noble trade.  You’ll need 34 minutes to watch this video…

Midori Haus

By the way if you were wondering what Midori Haus is it literally means green house. “Midori” is the Japanese word for green and “Haus” is the German word for house.  For us it has meaning beyond the literal green house.  All the values we mentioned above are embodied in it.

Design Process

We’ve been quite fortunate to work with two capable guys during the design process.  Last fall we chose to work with Graham Irwin of Essential Habitat to do both the home design work as well as the Passive House consulting.  He’s been gently guiding us and patiently educating us through the design process.  We appreciate his thoughtful style.  We first started with the layout of the master bedroom and bathroom.  Kitchen area took a while because we were trying to fit in a whole lot of stuff in a modest sized area.  There will be a deck on the south side of the house as well as a smaller one on the west side to give a feeling of indoor and outdoor connection.  The hallway closet will become the laundry room and there will be a small mechanical room on the south deck to hold the hot water heater.  Soon Graham will be shifting gears from architectural design to Passive House Planning Package (PHPP), where he will calculate the building energy consumption through a software model.

Another capable and patient guy we’ve been working with is Taylor Darling of Santa Cruz Green Builders.  As we iterated through the design Taylor provided the builder’s perspective to the team as well as coming up with the construction estimate.  Our goal is to come up with a realistic, solid design that could be built within a reasonable budget — basically, avoiding surprises.  We’ve heard stories where a homeowner took the approved/permitted plan out to bid and found out that it was way over the budget.  By taking out a small consulting contract with Taylor and having him involved in the design process we are mitigating the sticker shock.

While we iterated through the design we’ve been learning and shopping.  The free classes from PG&E are terrific value and we found the the monthly Passive House meetings to be a good place to learn and network.  As for shopping, Kurt has been diligently keeping up with various window manufacturers to get quotes.  Since this is the single most expensive category with the longest lead time it’s important that we play close attention to it.  Kurt’s been doing a great job on this.  We also drove around the Bay Area to look at doors, cabinets, tiles, fixtures, appliances and lighting.  After a while the collecting and compiling shopping data got to be a bit cumbersome so we’ve been keeping the master material selection list on a Google Doc shared by the design team.

Since we tend to be very detail-oriented and ask a lot of questions, both Graham and Taylor must have been taxed on their patience every now and then. Thanks guys, we appreciate your work and patience!

Passive House Example Up the Coast

Here is a brilliant video that show many details of the passive house construction.  It’s an affordable housing project near Point Reyes, about 100 miles up the coast from us.  Our project is a little different because it’s a remodel and not a new construction.  Still the passive house approach to insulation, airtight building, HRV and windows are all relevant for us.

Grab a cup of tea and enjoy this 30 minute video.

Rain and Drain

“Talk to everyone and ask them what they know…” was one of the advice we received recently.  This paid off in our quest for water solution.  The water problems we are addressing, in order of priority, are:

  1. Reduce moisture in the crawlspace under the house.  Moisture/water is essential for mold growth and during the rainy season the mold spores are happily multiplying under the house.  Because the house is not tightly sealed the smell of mold is present in the house during the rainy season.  My mother told me I developed asthma as a toddler living in a moldy house.  So, dry crawlspace means less mold and healthier indoor air quality. 
  2. Keep rainwater away from the house.  Directing the water away from the house will help keep the crawlspace drier and keep the house structure drier.  On one of the photos we saw from the house inspection was signs of water on the wooden posts under the house.  We want to prevent rot and keep the structure healthy too.
  3. Recharge the groundwater on the property.  Sending it down the storm drain alleviates our problem at the house but it still may contribute to erosion and depending on what is carried by the water from our property (e.g. asphalt bits from the roof, residual pesticides on landscaping, etc.) it may contribute to water quality issues.

We know from talking to our neighbors that there is good chunk of clay under the topsoil that prevents water from draining nicely.  It will eventually drain, but this is very slow.  Our neighbors have multiple sump pumps to drain the excess rainwater on their property to the storm drain. 

Getting a soils report done is quite expensive so we followed up on an idea that was mentioned by a contractor who installs solar panel.  He said, “Why not go through the yellow pages under septic system installation and ask them if they’ve done vertical leech field for water drainage purpose around the westside?”  Hmm… interesting thought.  That would be great way to find out about the geology and soils condition.  We would not have thought about talking to the septic people since we’re connected to the city sewer, but the application makes sense.  So I flipped the yellow pages and rattled off the phone numbers while Kurt spoke with them.  We ended up having Darryl from Battle Mountain Excavation dig a monitoring hole using a hand auger and installing a 2 inch PVC pipe for monitoring.

So what are we monitoring?  Well, we learned that just because you hit sand below the clay, it doesn’t mean that the rain water will simply drain into the sand.  Apparently there could be different water dynamics going on at different levels.  One way to measure how quickly the layer below the clay absorbs water is to put in a monitoring hole using a PVC pipe that is perforated on the bottom then sealing the top with clay to isolate the water level activity happening at the lower level.

The drilling work done by Darryl and his crew was informative. Basically there is good topsoil for the first 16″ then there is dark clay, followed by lighter color clay and finally sand.

Cross section diagram of the monitoring hole

The pipe is capped at the top to prevent rain from getting in.  Periodically we will measure the water level beneath the clay layer by dropping a tape measure with a float at the end to read the depth.

Dark color clay like this is beneath the topsoil.  Goes down to about 43 inches.

Then it changes to lighter color clay and goes down until 8 feet.

So, if we determine that the water level below the clay has capacity to absorb water during/after storms then we’ll likely have a french drain or a swale created in the backyard for drainage.

Also, if we have to pump the rain water to the storm drain we found out that it’s not so bad.  We talked to Dave Reid, a fellow water enthusiast with geology background and learned that there is a public online application that map the storm drain flows.  We used this to find out where the storm water went.  Here’s the link to this GIS mapping tool –

Storm water from our area goes to Neary Lagoon, a wetland in middle of the city next to the water treatment facility.  This wetland is a habitat for various wildlife, including the fish, Sacramento suckers that graze the bottom like vacuum cleaners.  They suck up layer of algae, invertebrates and bacteria.

Induction Cooktop

January 12, 2011
Back in September we took a kitchen design class at the local community college.  One of the things the instructor, Yvonne, mentioned was to be aware of the “power-sharing” and “boost” capabilities of induction cooktops because we can easily be misled about the true maximum power of a given unit from reading promotional literature.  Apparently the underlying assumption is that an user would never use all of the burners on the cooktop at the maximum capacity all at once.  OK, so we need to be wary of the marketing material and ask the right questions to get the facts straight.

The few times we browsed around the big box stores and asked the staff about the limitations of power sharing and power boost on induction cooktops we felt that we didn’t get any satisfactory answer.  Maybe the retail clerk at big box stores lacked the knowledge or were coached to answer in a certain way.  Maybe we didn’t ask the right questions.  Maybe we were confused.  The reality may be a little bit of all of that.

Well, I think I understand induction cooktop a little better today thanks to the wealth of information at  This site was recommended by Yvonne in the kitchen design class but I haven’t looked at it closely until now.  I happened to come across it recently while researching and collecting data on various kitchen appliances.  Here is one example of confusing induction cooktop specification I found –
  • The cooktop has 4 burners of different sizes (diameter) and power output 
  • The entire unit has power rating of 7.4KW at 240V
  • The 4 burners are specified as 
  1. 10″ @ 2400W/3200W
  2. 8″ @ 2200W/3000W
  3. 7″ @ 1800W/2300W
  4. 6″ @ 1200W/1500W
So I’m interpreting this to mean a 10″ diameter burner has 2400W power output that can be boosted to 3200W and so on.  Then, if you add up the first set of numbers (2400W + 2200W + 1800W + 1200W) it sums up to 7600W or 7.6KW, which is slightly more than the 7.4KW rating for the entire unit.  If you add up the higher power boost numbers (3200W + 3000W + 2300W + 1500W) then it sums up to 10,000W or 10KW and that is 2600W more than the unit is rated for.  It just doesn’t add up.  The manufacturer must have assumed that you will never use all of the burners at the maximum power output at the same time.  Incidentally, one of the reviews on Consumer Report for this particular cooktop mentioned that there was a burner cycling on/off problem and recommended readers to purchase extended warranty. Maybe this person pushed all the 4 burners to the max?
You might be wondering, “So, what do these numbers mean for the Midori Haus project?”   Well, I learned that depending on the power delivery requirements of the cooktop the kitchen may need to be rewired with wires that can carry higher loads and the house panel will need to be upgraded.  To get a really good understanding of this I encourage you to visit Induction Cooking: Kitchen Electricity 101 page at  They explain the nuts and bolts in detail I really like the water flow and water pressure analogy they use in describing basic electricity principles.
You know, I’ve been cooking on gas range for the last 20 years and like cooking with gas.  We know that induction cooktop is efficient and is better for indoor air quality.  So a happy solution is to have an induction cooktop in the kitchen and have a propane gas grill on the deck for the food we want charred.  By the way, induction cooktop delivers way more power than the gas stove.  The conversion factor for a gas burner (measured in BTU/hour) to induction burner (measured in kW) is BTU/hour = kWx 7185.  Using this conversion factor we can see that the l0″ burner in our example above that delivers 2400W or 2.4kW is equivalent to a gas burner that outputs 17,244 BTU, which is way more than what’s required in wok cooking (the most power hungry cooking) of 12,000 BTU.  For more details on the conversion factor please read the section “How Much Power Is What” in
Right now we are leaning towards the 30″ 4 burner induction cooktop from Miele.