Keeping Cool During Heat Wave

We continue to be very happy with our Passive House.

Last week we had a bit of heat wave here.  It was unusual for Santa Cruz to have 3 consecutive days of temperatures in the mid to high nineties.  The chart below show the daily high and low temperatures (in Fahrenheit) in our area.  The Weather Cat weather station is located just 2 miles away from Midori Haus and is in a similar residential area so it provides good representative historical weather data for us.

What was really unusual about the heat wave last week was that Santa Cruz was about 10 degrees warmer than San Jose.  Normally it’s the opposite.  Have a look at this map below.  Even if Santa Cruz is south of San Jose the cool ocean temperature keeps the area mild and comfortable.  So I was surprised on Thursday last week when we drove back from Berkeley to see the temperature sensor on my car showing 96 degrees in Santa Cruz when it was only 85 degrees in San Jose. 

When we got home and stepped into the house it felt comfortable.  And we have no air conditioning.  Because of the super insulation and air tightness of the house the temperature inside the house stayed in the mid seventies during the entire time.  Here is an example of the temperature reading inside the house showing 23-28 degrees cooler than the outside.

Plotting the periodic temperature readings on this graph you’ll notice that the internal temperature stays in a narrow band while the external temperature swings wildly.

While passive house dramatically retards the heat transfer from the outside to inside (during summer) and from the inside to the outside (during winter) it does take a little bit of conscious action by the homeowner to optimize the comfort.  Let me show you what I mean.

First is shading.  Our deck that extends to the back yard faces south.  This is great in the winter because the 2 rooms facing south receive lots of good solar heat gain when it’s cold and the sun angle is low.  During the summer we want to keep the sun out.  So on Wednesday evening Kurt took out the canvas shade cloth and installed them over the arbor.  Originally we had intended to grow some plants to provide natural shading, perhaps grapes or kiwi.  But we chose not to go down that path because the shade cloth provides us with more flexibility.  After the first summer we decided to keep these shade cloth as a permanent seasonal solution rather than rely on plants because it’s easier to maintain.  Here’s a picture of that.

 Another part of the shading is inside the house.  We have these roller shades installed over the windows.  The ones on the south side of the house are all made of light-blocking thicker material we got from Advanced Blind & Shades,  and they are manufactured locally.

Then there is the setting on the heat recovery ventilator (HRV).  To minimize bringing in excess heat during the heat wave we set the control on the Zehnder ComfoAir 350 HRV to “A” during the day to reduce the ventilation flow down to 23.5 cfm from the normal 95 cfm at “2” setting.

The Zehnder ComfoAir 350, as with other heat recovery ventilators, has the ability to perform passive night time cooling in climates where hot daytime summer temperatures are followed by cool evening temperatures. These are climates in which one would normally open the windows at night. 
Using the HRV “Summer Bypass Mode” allows all the benefit of night time cooling with the windows the added benefit of retaining the filtration of air introduced into the home interior. It allows for a cooling to a precise user selected set point and then resumes its temporarily defeated heat exchange function.

Finally, we open the windows and let the cool air in during early morning.  As you’ve seen from the daily low temperature in from the Weather Cat table above it gets nice and cool overnight.  Typically in the mid to high fifties even during the heat wave.  This really helps to reset the internal temperature before the day heats up again.

By the way, this night or early morning cooling works because the ocean temperature is pretty constant and cool throughout the year.  The table below is the average ocean water temperature from NOAA.  You can see from the table that the water temperature just a mile away from our house is abut 56 degrees Fahrenheit, plus or minus 3 degrees.  Once the sun goes down the cool ocean water cools the air so the overnight temperature is consistently cool.  That’s why homes in Santa Cruz don’t have air conditioning.

Because we don’t have air conditioning we don’t use extra electricity during hot weather.  Our electricity usage continues to stay pretty low during the heat wave of May 13-15, 2014.  Below is the screen shot from PG&E, our local utility, showing our electricity usage for the current month. 

We are happy to be comfortable in our Passive House that uses very little energy.

What’s New? What’s Old?

“Is this part of the original house?” is one of the questions people ask when they visit Midori Haus.  We feel complimented when people ask that question because we did put fair amount of effort into re-using materials to give it the look and feel of a vintage house that was originally built in 1922.  When we didn’t have any specific old looking items to re-use we bought new items that were made to look in the old style.

An example of this is the push button switch for the lights.  The house did not have push button switches when we bought it in 2010 but we are pretty sure that the orignal house did.  So to give it the original look we bought push button switches and switch plates in oil-rubbed bronze finish from Rejuvenation in Berkeley.

Most are simple on/off switches where you press the top button to turn lights on.  To turn the lights off you press the bottom button.  Some of the switches have a dimming function where you press the bottom button for on/off and the top is an adjustable dial to control the light intensity.  We chose to use these antique looking switches for pure decorative purposes.  There are no energy efficiency advantages.

Let’s look at the hallway bathroom door for a good mixture of old and new items.  The frosted glass on white door with the glass door knob has a vintage look.  When friends saw this door before the renovation they would say, “That looks like the door in my grandmother’s old house,” or “My basement door in my old bungalow has a door just like that.”

 We added the stained glass window above the door to let more light into the hallway.  People often perceive this to old but we got this new from The Bright Spot.

The door, the knob and the trims are original with fresh paint.

 We kept the built-in storage unit in the hallway.  These front got some fresh paint and the inside was simply cleaned.  It smells of old wood when you open the drawers and it’s part of the charm.

Most of the floor is original.  We removed the floor coverings (tile, carpet, linoleum) and had the original wood floors refinished.

The windows on the front of the house retained the same positions and size.  The triple-pane, Argon-filled fiberglass windows have a much better performance than the old single pane leaded window.

We did re-use the trims around the windows.  Santa Cruz Green Builders did a great job of matching the wood covering the deep window sill with the original window trims.

Notice the patched marks of nail holes on the window trim.  This is evidence of prior homeowners  installing curtain rods multiple times on this window trim.

 

  The mudroom bench and cabinets are new.  This practical set of built-in furniture was made by Loughridge Cabinets in Scotts Valley.  When you walk into the mudroom/kitchen area from the side door you can park your groceries on the bench, hang your hat and coat on the hook, and sit on the bench to take your shoes off.

Speaking of the mudroom, we did use a piece of the old mudroom in our new kitchen.  The breadboard on the wall was re-used on the breakfast bar in the kitchen.


In our old kitchen the gas water heater was next to the stove, strapped onto the wall.  The gas stove and the water heater shared a flue going up through the ceiling to exhaust above the roof.

 

As you enter the front door you’ll see this tidy shoes storage to your right.  We ask all visitors to take their shoes off in our house and this is one of the places where you can store them.

 

Also made by Loughridge Cabinets, the concept of the Japanese “getabako” is expressed in the arts and crafts style.This is built back into the wall and protrudes through the dining room. In the dining room the back side of the shoes storage cabinet looks like a nice stand.

 The buffet is the original built-in furniture that stayed in place during construction.  It was covered up for 13 months while the crew worked around it.

French door between the dining room and kitchen is also original piece of the house.

 Finally, I added a touch of Japanese influence in this arts and crafts house by re-using my other’s old kimono as cushion covers.

Solar Thermal System

December 6, 2013

You’ve got to be careful if you don’t know where you’re going because you might not get there.
– Yogi Berra

It took us a long time to decide on the system to provide hot water for the house.  Partly because we were going through a steep learning curve but mostly because the destination we set out for was somewhat broad.  It was analogous to going on a road trip by having the target destination specified with just the city name but not the specific street or the address.  So we were very careful because there were were many paths to get there and the recommendations from various experts did not converge.  Each expert we spoke with had a different take on the path and each one of them had a very strong opinion. We were so flummoxed that we stopped construction for 2 months while we sorted this out.  One lesson we learned was that there are many different ways to achieve water heating and you need to decide on the right solution for your situation.  There is no silver bullet.  Another lesson is “How you frame the question influences the solution,” and finally,”The clearer the goal, the clearer the path to the destination.”  I will spare you the drama of this journey and will instead present the journey in a summary fashion broken down into 4 phases – (1) Requirements, (2) Design, (3) Installation, and (4) Results Measured.  Before we embark on this summary journey, take a peek at the finished mechanical room.

(1) Requirements

The broadest statement of our goal was to “Have a hotwater system that minimizes the carbon footprint for our draw profile.” Now let’s break this down into 2 parts – draw profile and carbon footprint.

The “draw profile” or how we use hot water can be categorized into 3 parts.  First is the day-to-day use of washing hands (short draw) and showers/baths (long draw).  The second part is the hot water demand from appliances, specifically dishwasher and washing machine.  Both of our appliances (Miele Futura Dimension dishwasher and Bosch Axxis+ clothes washer) are quite efficient in their water usage and have their own water heating elements built in.  This means the warmer the temperature of the incoming water, the less energy it will take to heat the water to meet their program cycle.  The third part of our draw profile, the ofuro or soaking tub, represents the ultra long draw.  You see, one of the outcomes I wanted from Midori Haus was to have a par-boiled experience of soaking up to my chin in hot water that was at least 110F degrees.  The soaking tub we selected (MTI Yubune #77) has a capacity of 155 gallons.  This ultra long draw is not an everyday event but a random, once in a while event that didn’t fit into the average household hotwater draw profile.  This is a luxury behavior we decided to keep within scope to promote the happiness and well-being of the occupants of the house.

You may ask, “Why do you want to minimize carbon footprint?”  The simple answer is this:  Because we want to do something tangible in our personal space we control that reduces impact on climate change.  “OK, that’a a noble goal,” you might say, “and tell me how your choice in water heating system affects climate change.” Well, you can heat water at home by different means.  The sun can directly heat the water using the solar thermal system.  Electricity can heat the water using heat pump technology.  Gas boiler can heat the water.  Each approach has pros and cons.  The most important outcome we desire is to minimize the use of source energy at power plants.  Why?

  • Unless you live off the grid (i.e. not connected to the utility infrastruture where you produce electricity at your home and having a battery storage system to power your house when the sun is not shining) you’re getting your electricity from your utility company.  Should you be inclined to watch an entertaining and informative video on electricity for 5 minutes, have a look at Energy 101: Electricity Generation.
  • You’ll note from the video that the electricity power plant is a big steam engine that turns the turbine which spins the magnet to produce electricity.  The amount of energy needed to heat the big steam engine is about 3 times the amount of electricity produced.  If you have the appetite to consume mathematical formulas that explain the Rankine cycle and the efficiency of power cycles I invite you to visit Thermopedia.  There are different ways of turning the turbine (dams at hydro electric plant, wind farm, burning coal, nuclear) and in the worst case scenario for every 1 unit of electricity that reaches your home 3 units of energy was burnt at the source (power plant).  So, if we minimize the use of electricity at home including water heating we minimize the carbon emissions at the power plant and reduce our impact to climate change.

With the focus on minimizing source energy, we refined our requirement further by selecting solar thermal system with a tiny solar electric PV panel to avoid drawing any electricity from the grid to run our hotwater system.  When we have continuous cloudy, rainy days the solar thermal system will need backup heating.  For this we chose a gas boiler since we planned to have an outdoor barbecue plumbed with natural gas.

With these requirements defined let’s look at the design of the solar thermal system at Midori Haus.

(2)  Design

We gave our requirements to Patrick Splitt of App-Tech to design the solar thermal system.  He designed an elegant system to meet our needs and provided us with detailed drawings and equipment list.  Instead of sharing the detailed design on this post I’ll briefly describe system using my diagram below.

At the heart of the system is the indirect tank from TriangleTube, model SME120.  This is a tank within a tank where the water stored in the outer tank (66 gallons) heats the inner tank (105 gallons) that is used for heat storage and domestic hot water.  Note that the water in the 2 tanks never mix — the outside tank water is used strictly for heat exchanges and the inner tank is used inside the house for washing and bathing.  The tank has 2-inches of polyurethane foam insulation built into the tank to minimize standby loss and we further wrapped the outside of the tank with few layers of bubble foil insulation to really keep the heat in.

The water in the outer tank is heated by the heat exchanger coil in the bottom of the outer tank.

When the sun is shining the tiny photovoltaic (PV) panel generates electricity to power the pump that circulates propylene glycol in the heat exchanger coil up to the Heliodyne solar thermal panel.  This is a clever design because the pump would never circulate the heat exchange fluid to cool off at night.

If the temperature of the hot water in the inner tank drops below 120F the aquastat sensor would trigger a signal to kick on the gas boiler to heat the water in the outer tank.  The CC125S Challenger Solo Boiler from TriangleTube is designed to work together with the SME120.  It is energy efficient with up to 94% AFUE.

The hot water in the outer tank is also used for space heating inside the house.  The thermostat in the hallway controls the pump to circulate hot water through the water-to-air heat exchanger (think of this as a box similar to car radiator) located next to the heat recovery ventilaor (HRV).  Details of the HRV will be covered in a different post.

The combination of SME120 and CC125S allows us to maximize the use of heat energy from the sun.  This is another clever feature of the design we like because this allows us to use the hotwater heated by the sun at night and reducess short cycling caused by “cold water slug”in the pipe.

(3) Installation

The solar thermal system was installed by Duane Wilson of Wilson Hydronics in the mechanical room. The mechanical room is a compact 38 square feet space located on the south-west corner of the house.  Note that the mechanical room is outside of the air-sealing envelope of the house.

The solar thermal panels are made by Heliodyne, a solar thermal company located in the San Francisco Bay Area.  We used 3 of the flat plate collectors (Gobi 408 001) and rack mounted them on the south roof at 45 degrees angle.  Installing the panels at an angle helps to product more heat in the winter when the sun angle is lower.  

The copper pipes that run from the mechanical room to the panels on the roof are insulated with 1″ self sealing Armaflex tubes.

The controller to run the pump that sends propelyne glycol to the panels on the roof is from Art-Tec Solar.  The small PV panel on the roof next to the mechanical room generates electricity to operate the pump to circulate glycol through the solar collectors on the roof.  This ony operates when the sun is shining so we avoid cooling off the glycol heat transfer fluid  at night or during rain.

The vent you see on the flat roof is for the Challenger Boiler.

SME 120 indirect tank — before and after bubble wrap insulation.

 

Challenger boiler – CC125S.








































To minimize scaling in the hot water system we installed the Heater Treater from Falsken Water Treatment System.

There are many more interesting stuff in the mechanical room, such as expansion tanks, pumps, check valves, etc.  If you want to see the full detail, I invite you to attend one of our public tours of Midori Haus.

(4) Results Measured

“Is it comfortable?” and “How much energy did it take to provide adequate hot water for space heating?” are the two questions that are important to us.  So I will share our data from WELserver and PG&E to answer those questions.

Is it comfortable?  Yes, it feels comfortable in the house.  Let me show this to you with data.  Below is one of the signs I posted on the wall for the Passive House Days tour about 1 month ago.  The green screenshot on the right is from the WELserver we installed in our house reporting the temperature, humdity and VOC measurements from different rooms in the house.  There will be a different post on WELserver to describe it in greater detail.  The left side overlays the temperature measurements on the layout of the house.  As you can see, this data shows the house having a comfortable temperature range of 68 – 72 degrees Fahrenheit in the middle of the night when the external temperature is at 48F.

A more recent example displays the low heating demand for the house.  Data below was taken this morning at 8:30 A.M., after the sun had been shining for 1.5 hours.  Overnight low temperature was a very cold 28F.  This is very cold for our mild climate here and we did an overnight experiment where we turned off the heat recovery ventilator (HRV) to see how the house performs by relying on the super-insulation and the ultra tight air-sealing to keep the internal heat gains inside the house.  Below you see the temperature in the rooms of the house dropping a few degrees to 64 – 67 degrees Fahrenheit range.  This means that the heating system only needs to bring up the air temperature in the house by few degrees to keep it comfortable.  When energy modeling calculation was done using the Passive House Planning Package (PHPP) we learned that the house would need less energy than a hair dryer would use to keep it warm.

One anomaly you may notice below is the wide temperatures range of the exterior – south deck is 71F and the front porch is 33F.  In this case the front porch temperature is more representative of the actual outside temperature.  The south deck receives direct sun and the sensor gets pretty warm after having the sun beating down on it for 1.5 hours.

How much energy did it take to heat the hotwater?
The solar thermal system needs a boost from the boiler every now and then when the temperature of the inside tank dips below 120F.  This could be caused by standby loss (tank losing heat to the cold air surrounding the tank) or when there is a big draw (filling the soaking tub).  We used the soaking tub about 3 times during the summer and the temperature of the hotwater in the inner tank never dipped below 120F so the gas usage on our utility bill from PG&E is mostly from the boiler.  The few therms we used in the summer is probably due to the outdoor gas barbecue.

Our natural gas usage is indicated by the blue line in the graph above.  As you can see the gas usage is just a fraction of what similar homes use.  The definition of similar homes represented in this graph are 100 homes of similar size within 0.6 miles radius that use natural gas for space heating.

What About Cost?

You may have noticed that “lowest cost solution for minimal hot water use” was not part of our criteria in designing our solar thermal system.  We wanted to be comfortable and splurge with a nice soak every once in a while.  After agonizing over the high price tag we stuck to our goal of minimizing our carbon footprint by avoiding the use of electricity for hot water heating.  So we accepted the high price tag to implement this elegant solution and we hope this system will be with us for a long time.   We are using about 350 therms/year less than similar homes in the area but with natural gas prices being so low it would take a long time to pay back the higher cost of this system compared to some other approaches. The bright side is that we won’t feel the impact of natural gas price hike in the future because we use so little of it.  Also, we have resiliency built into our dwelling becaues we will have hot water during blackouts and gas outages.  As long as the sun is shining we will have hot water.

Conclusion

The solar thermal system we implemented is just one approach to heating water at home.  There are many paths to generating hotwater.  We chose this approach because of our desire to reduce carbon footprint and meet the needs of our hotwater usage.  It’s not a solution for everyone.  Some of our friends who are remodeling their homes in an environmentally conscious way have adopted a different approach.  They are going all electric by installing PV on their roof and are using heat pump water heater that could generate 3~5 watts of hot water for every 1 watt electricity used by the pumps and fans.  They also were concerned about carbon and chose to avoid natural gas because of methane leakage at the fields where natural gas is extracted.  I’m happy for them for choosing a solution that best meet their requirements.

What’s important, I believe, is to be clear about your desired outcomes and decide for yourself and share the results with others.  The real validation of the system is when the contractor who installed your system implements the same at his house.  We’ll see if this happens.

Paperstone

November 18, 2013

About 80 people toured Midori Haus last weekend during the International Passive House Days.  There were many insightful comments and questions from the guests about energy usage, heating system, cost, and many more.  One question visitors asked me several times was about Paperstone, our choice of countertop material.  When people asked the question, “Can you put hot things on it?  Will it leave a mark?” I could not answer it because I didn’t know.  Frankly, I was too chicken to try it out.

A few nights ago I remembered that we have a piece of Paperstone cutting board tucked under the sink and thought, “Well, if this one gets burnt from an experiment I won’t feel bad because it’s hidden most of the time anyway.”  Below I will share with you the photos from my experiment.

This is the piece of paperstone cutting board I will use for my test.  Notice there are no marks.

I’m using a cast iron skillet to cook chard at high temperature.  Notice the number “9” on the induction cooktop and the steam under the cover.

Now for the test.  The hot skillet is placed on the paperstone.  To give the skillet the maximum opportunity to make a mark I left the hot skillet on the Paperstone cutting board for 20 minutes.

Voila!  No mark on Paperstone cutting board.  Now I won’t worry about putting hot items directly on my countertop.

Passive House Days: November 9 & 10

November 3, 2013

We invite you to visit Midori Haus, the first Passive House in Santa Cruz County during the 2013 International Passive House Days.  

Dates/Times  
9-November-2013 (Sat)  1:00 p.m. – 5:00 p.m.
10-November-2013 (Sun)  1:00 p.m. – 5:00 p.m.

See the tour flyer for details.

What is Midori Haus?   Midori
Haus is an example of how
a 90-year old building can be both beautiful and ultra energy efficient.  We kept the original footprint of the
3-bedroom, 2-bathroom California bungalow originally built in 1922.  During 2012 it was retrofitted to
Passive House standards with the aim to combine extreme energy efficiency and
comfort of Passive House with the aesthetics of Arts and Crafts style.

What is Passive House? 
Passive Houses stay
at a comfortable temperature year round with minimal energy inputs.  Buildings make efficient use of the sun
and heat recovery so that conventional heating systems are unnecessary.  The materials and systems are modeled
to a stringent performance standard using PHPP (energy modeling software) that
aims to limit the annual  energy
demand for primary heating and cooling of the house 15 kWh/m2   (1.4kWh/ft2
or 4.75kBtu/ft2) per year. 
This energy target is about 80% less than what  conventional homes use for heating and cooling.

Steam Oven

August 16, 2013

The Steam-Convection Oven is my favorite of all the kitchen appliances at Midori Haus.  At our previous home we had a gas cooktop and gas oven.  I’ve been cooking on gas stove top for over 20 years I liked cooking with gas a lot.  That is until we started taking energy efficiency classes at PG&E.  Let me paint a picture of what used to take place at our condo.

We learned that backdrafting occurs when there is negative pressure in the house.  This can happen when the volume of air removed by the exhaust fans (kitchen vent hood, bathroom exhaust fans) is greater than the volume of air that can easily enter the house such as through open windows.  At our condo we had all the windows and doors closed in the winter time because we didn’t want the 47 degree air coming into the house.  When we turned on the vent hood for cooking the make up air would need to come from some place that has the least resistance.  At our condo this was the gas wall furnace.  When the kitchen vent hood is sucking up the air above the gas oven to remove the combustion byproducts and cooking odor the make up air is coming into the house from the outside via the flue of the gas furnace on the wall dragging all the dust, particles stuck in the flue into the house.  Yuck.  After we learned about backdrafting we started this drill of opening the windows before we turned on the oven and vent hood to avoid bad air coming into the house.  In the winter this brought in cold air and the house never seemed to get warm.

Fast forward to present where we don’t have any gas combustion appliance in the house at Midori Haus where the Heat Recovery Ventilator provides constant fresh air.  We no longer have to do this routine of opening the window while kitchen vent hood is on.

Kurt gets credit for finding the Gaggenau BS 270610 Steam Oven on eBay.  Yes, we bought an expensive piece of kitchen appliance on eBay to save thousands of dollars and it’s working great.  With this oven I can control both the temperature and humidity separately and cleaning the oven is a really easy.  For baking coffee cakes I set the temperature to 340F and 30% humidity.  For making boiled eggs or steamed rice I set the temperature to 210F and 100% humidity.  It took me a while to work up the courage to make rice in the steam oven because I just could not imagine rice turning out well in an oven.  And I’m happy to have overcome that mental block.

Cooking rice in the steam oven requires the unperforated tray to be filled with 1/2 pound of rice with 2 cups of water and cooked in the steam oven at 210F at 100% humidity for 30 minutes.  Here are some photos:

Basmati rice with some water in the steam oven tray

The tray is inserted into the rails in the steam oven

Temperature is set to 210F at 100% humidity

Timer is set to 30 minutes

The oven is plumbed with filtered water and the steam fogs up the cavity

At about 10 minutes left in cooking time I throw in a bowl of leftover chili

Rice and chili is done!

This method of cooking rice works well with short-medium grain rice (aka sushi rice) too.

I’m sad to say that we’re not cooking rice much these days.  Why?  Because we want to minimize exposure to arsenic.  Consumer Reports came out with a study that showed rice products (brown rice, white rice, organic baby cereal, brown rice pasta, etc.) contained arsenic, many at worrisome levels.  If you follow the link above and read the report you’ll see a chart that lists products and levels of arsenic detected.  For example, Trader Joe’s Organic Brown Rice Fusilli pasta contains total arsenic level of 347 to 384 parts per billion (ppb).  We used to buy that often and liked it until we found this report. The thing I found curious is that although the level of arsenic found in the rice pasta is high there is no standard for arsenic levels in food.  If you look at the EPA standard for arsenic in drinking water its 10 ppb.  Strange, isn’t?

Lighting

February 28, 2013

According to U.S. Energy Information Administration (EIA) estimate 461 billion kilowatt-hours were used for lighting by the residential and commercial sectors in 2011.  This is about 17% of the total electricity consumed by both of these sectors and 12% of total U.S. electricity consumption.  This government website contain interesting data.  For example, looking through some of the tables on this site I noticed that 1995 was the year when electricity use by the residential sector exceeded the electricity use by the industrial sector.  But I digress.  This post is not about historical electricity consumption data but about lighting choices we’ve made at Midorihaus.  For those who want to explore the rabbit warren of historical energy data I invite you to look at this report from EIA.

We wanted 3 outcomes for lighting at Midorihaus: (1) good light quality that is functional and pleasing, (2) energy efficient performance of the materials, and (3) aesthetics of the lighting fixtures to match the overall Arts and Crafts style of the Bungalow architecture.  These 3 outcomes were equally important so naturally Kurt drove this area.  Not only does he have the gift of easily juggling and synthesizing different aspects and ideas all at once he also has over 2 decades of analog photography experience which trained his eyes to notice different qualities of light plus the science background to tie it all together.

The Arts and Crafts aesthetics part was fun.  Looking at books on Arts and Crafts style and visiting lighting stores to look at fixtures were enjoyable.  Our neighbor turned us on to The Bright Spot website and we were delighted to find reasonably priced Arts and Crafts style lighting fixtures.   We bought most of our lighting fixtures from The Bright Spot.

Researching and buying the light bulbs took a bit more time.  The light quality and energy efficiency aspects were challenging because evaluating light quality is subjective and the technology, especially with LEDs, is changing rapidly.  We’ve heard leaders in this field talk about how in 2 years the LEDs will be much better performing at lower cost than it is today.  But we can’t wait 2 years — we need to put some kind of lighting into the house now.  So, here are the steps we took to figure out what light bulbs to use:  1) Visited lighting retail shops to check out what they had in stock and compared them on their display board with dimmers; 2) Bought a number of CFLs and LEDs that looked good at the store; 3) Put the sample light bulbs in the fixtures in different rooms to note what we liked and didn’t like; 4) Measure actual performance of the light bulb (rather than trust the printed stuff on the box).

1) Visiting lighting retail shops.  We started locally at Riverside Lighting & Electric in Santa Cruz.  After identifying few different types of Compact Flourescent Lamp (CFL) and Light Emitting Diode (LED) bulbs we asked the salesperson if we could use the display board with a dimmer to see the lights side by side.  By putting different things near the light, such as your hand or paper with color, you can judge with your eyes what looks pleasing to you.  Since we specified dimming switches in several of the rooms it was important to have a bulb that performed well in dimming function.  Some of the bulbs had a noticeable color changes or reduced sensitivity when dimmed.  Other shops we visited were City Lights in San Francisco,  Bay Lighting Supply in Santa Clara, Light Point in Menlo Park, and Rejuvenation in Berekely.  City Lights in San Francisco had a wide selection of light bulbs and separate departments and staff for lighting fixtures and light bulbs.

2) Buying CFLs and LEDs to try at home.  We bought the CFLs and LEDs below to try out in the fixtures in our home.

CFL Bulbs:  GE, TCP 850 lumens, TCP 750 lumens

LED Bulbs:  Green Creative, Energetics, Philips, LEDwiser

3) Try the light bulbs in the lighting fixtures.  Seeing the bare bulb in the lighting store is nothing like seeing the bulb in the fixtures in the actual room in the house.  It was amazing to see how many different things can affect the overall light quality — the paint colors of the wall and ceiling, the direction the lighting fixture, the type of material used in the lighting fixture (colored glass, metal borders, etc.), furniture in the room, and time of day.  We found that while the labels on the boxes (color temperature, lumens, watts) contain information that will guide you on narrowing down the initial selection, the actual “feel of the light” in the rooms determines the best fit.

Below are some pictures of our lighting fixtures in various rooms.

Office & Guest Room:  Kenroy 806362ORB Builders Modern Mission Builders Modern Mission Ceiling Light 3 Lamp with LEDwiser bulbs.
Office:  Kichler 70598 Zen Table Lamp with Philips bulbs.

Kitchen Breakfast Bar:  Kichler 65292 Joya Mini Pendant with Philips bulb.

Dining Room:  Kichler 65290 Joya Chandelier with LEDwiser bulbs.

Living Room:  ELK Lighting 7647-5 Elysburg 5 Light Chandelier with LEDwiser bulbs. 

 
Deck:  Kichler 9031DCO Morris Longbody Outdoor Lantern with LEDwiser 

Porch:  Kichler 9838DCO with LEDwiser

Bedroom:  Sconce with Green Creative bulbs.

You may have noticed that we used quite a bit of LEDwiser bulbs.  Kurt met the entrepreneur behind this up and coming company in San Jose through Cleantech Open and we were impressed with their product.  LEDwiser’s product had the best lumens/watt ratio and had good directional coverage.

4) Measure actual performance.  We used the Kill A Watt to measure the watts drawn by the light bulb.  This was an interesting exercise to see if the actual electricity consumption measured on this device is what’s advertised on the box.  We plugged in the Kill A Watt into the electrical outlet on the wall then plugged in a table lamp to the Kill A Watt.  Then different light bulbs were screwed into the lamp to measure their electricity consumption.  We found that all of the LEDs we tested measured below the watts advertised on their boxes.  The TruDim CFL from TCP had the characteristic of shooting above the advertised wattage when warming up then settled near the advertised number.

Performs as advertised
Overshoots while warming up

If you’re interested you can check out the summary of our test.  Once we decided which bulbs we liked we totaled up the numbers and placed orders with the respective companies.

…And then there’s Title 24

One area where we felt “handcuffed” in our lighting fixture selection was the kitchen.  Lighting in kitchen is subject to energy efficiency standards specified in California Code of Regulations, commonly known as Title 24.  Instead of using the Arts and Crafts style ceiling mount fixtures with LED bulbs we had to get a very specific kind of lighting fixture that forced you to using a specific type of high efficiency lighting.  Perhaps this code was meant to prevent homeowners from using 100 watt incandescent light bulbs all over the kitchen. The intention is good but it makes it harder for those of us who want to have better energy efficiency than code minimum.  Because this is part of the code where building inspectors check and there are limited number of manufacturers and models we had little choice.

If you’re curious about what Title 24 details take a look at this website, Title 24 Express, which seems to have the layman’s explanation of Title 24 in an easy to read layout.

If you are really into government regulations and want to read more about Title 24 then enjoy this government site.

Kitchen and Mudroom

December 14, 2012

We kept the same total footprint of the house — interior usable space of 1,569 square feet.  The room layout stayed the same, with the exception of the kitchen where we knocked down the wall between the kitchen and the mudroom and took the space from the bedroom closet.

Old layout

The original house had an exterior door into the mudroom that held the washer and dryer.  The kitchen had 3 openings.  One opening between the kitchen and the mudroom, a door leading to the hallway and another door into the dining room.  The sink faced the west windows and at the left end of the countertop was the ventilated vegetable storage (aka California Cooler) where the exterior wall had vents.  The gas-fired water heater was in the south-east corner next to the gas stove and range.   A ceiling fan vented to the outside could be operated by pulling the chain.  The north wall had a cute built-in cabinet.

The new layout

The new layout still has a mudroom, but there is no longer a wall separating the mudroom from the kitchen.  The door into the mudroom extends out to a small deck where we’ll have a outdoor gas barbecue.  A bench and cabinet is placed on the south wall and this is where we’ll hang out coats and take our shoes off.  Looking straight in from the mudroom door you’ll see a little desk area where we intend to do paper mail sorting, recipe lookup and such.  Pantry is next to the desk.  The breakfast bar wraps around the outside of the sink, countertop and cooktop.  There is no longer a door to the hallway and the cabinets cover the east wall.  We have 2 sinks in the hopes of having 2 cooks in the kitchen working side by side in peace.  The door to the dining room changed from the swinging type to a larger pocket door.

Here are some “before photos” of the original kitchen.







Mudroom:  As viewed from the kitchen.  Washer and dryer took up most of the space in the mudroom.  Note the bead board wall behind the washer and dryer.  Speaking of wall, the kitchen had the lovely funky plastic fake brick thing above the wainscoting.

Kitchen sink:  The kitchen sink and the countertop was a little taller than the standard countertop height I’m familiar with.  The windows above the sink and countertop provided pretty afternoon light.  On the right side of the sink is a vegetable storage space known as “California Cooler.”

California Cooler:  The upper and lower vents next to the lattice fence provided the cool breeze to flow through the wire mesh shelves to keep the fruits and vegetables fresh.  If you’re curious about the California Cooler, read what another blogger wrote about them.

Fridge, Stove, Water Heater:  The gas water heater in the kitchen was literally placed in the center of the house.  The seismic strapping prevented the use of the cool “ironing board feature,” (we think).  The gas stove/oven was a O’Keefe & Merritt from the 1950’s.  It was very cute but we didn’t want to have any gas combustion appliances in the house so it was sold on Craigslist.  The refrigerator was only about 5 years old and it too got sold on Craigslist.

Hidden Chimney:  When our designer took measurements of the house there was a small amount of unaccounted space between the closet and the kitchen.  This mystery was solved during the deconstruction where a chimney was revealed in the wall cavity behind the water heater.

Upper Cabinets:  A cute glass door showed what was stored in the cabinets.

Lower Drawers and Bins:  Below the upper cabinet was a countertop covered in blue linoleum.  These bins in the kitchen must have been used to store flour or some grains back in 1920’s.  As charming as these were we chose not to keep them.

Here are the “work-in-progress photos” of the new kitchen:

Mudroom Bench and Cabinets:  The door to the mudroom is to the right of the bench and we’ll probably use this door 90% of the time.  So, we’ll come in through the door and kick off our shoes then place them under the bench.  Next hang the jacket on the hook.  If we were riding our bikes and we had helmets and gloves they may go in the upper cabinet.

Desk and Communication Center:  The little desk in the corner of the mudroom will be used for day-to-day household paper and communication.  The slots above the desk will be used to sort mail.  Under the desk will have network devices and the desk will have a small computer that will display the house monitoring data (energy consumption, temperature and humidity).  To the left of the desk is the pantry.

Pantry:  Next to the desk is the pantry with pull-out drawers.

Upper Cabinets:  The kitchen cabinets are made of cherry wood in Shaker style with soft-close mechanism for doors and drawers.  Crown moulding a the top that bridge gaps between the cabinet and the soffit adds just the right touch to make the kitchen have the arts and crafts feel without being too fussy.  Loughridge Cabinets of Scotts Valley made these and we’re really happy with their workmanship.

 Countertop:  In these two photos you’ll see Taylor applying adhesive to the top of the cabinet then fitting the carefully cut PaperStone countertop with Jacob’s help. We looked at various materials for the countertop and the breakfast bar.  Going to a retail shop where you can see green product samples as well as get information from knowledgeable staff made a big difference.  We shopped for the countertops and breakfast bar in the spring of 2011 by going to Ecohaus in San Francisco (now closed) and GreenSpace in Santa Cruz (still open!!) and looked at many different green countertop products.


There are many different types of materials and color choices within each product line.  If you’re considering the pros and cons of different materials I invite you to take a look at the Countertop page of Green Remodel Forum where there is a detailed description of various materials by attributes.  Our selection criteria came down to 2 key points:  sustainability of the material and aesthetic fit with the California Bungalow style.  We chose a product called PaperStone in mocha color for the countertop.  It’s a sensible product that is made with FSC certified post consumer paper product held together with petroleum-free resin.  Details of the PaperStone material can be found here.

Tile:  For the kitchen backsplash we used the Debris series from Fireclay Tile which is made with 60% recycled material in the Bay Area.  While many distributors carry Fireclay tile we liked visiting the showroom in San Jose.  Picking out a dozen different sample tiles and taking it back to our kitchen to see which best matched the color scheme was very helpful.

Re-using the bead boards:  Remember the bead boards on the wall of the original mudroom?  They were re-used to surface the breakfast bar.

Insulation

October 2, 2012

We want to be comfortable in the house.  There is a narrow band of temperature and humidity range we human beings are comfortable at.  The temperature-humidity chart below show the comfort zone to be in the low 70’s to 80 degrees Fahrenheit, which is about the ambient temperature in Hawaii.  Since less than 1% of the population of the U.S.A. live in the 50th State most of us encounter climates where the outdoor temperature is either too warm or too cold.

So to keep the inside of the house comfortable the shell of the house would need to slow down the transfer of heat between inside of the house and outside of the house.  This (either keeping the interior cool when it’s blazing hot outside or keeping the interior warm when it’s frigid outside) is what insulation does.  What type of material to use for insulation and how much to use depends on where you live and the goal you’re trying to achieve (performance and cost).

US EPA’s Energy Star site has this insulation map and accompanying table that shows different climate zones and the recommended level of insulation.  You’ll notice numbers preceded by “R” on the table such as R30, R25, R60, etc.  The R-value is the unit of measure for resistance to heat flow.  The higher the R-value the less heat flows between the inside and outside of the house. Different materials performance as insulators and you can find a table of R-value for different materials in this Wikipedia article.

Rather than use a generic table of recommended R-values we had our Passive House consultant and designer, Graham Irwin, perform the analysis and calculation using the Passive House Planning Package (PHPP) from Passive House Institute.  When all the details of the house (climate data for our zip code, house orientation, materials used etc.) are entered into the PHPP software it will calculate the amount of energy needed to heat and cool the house.  We have specific energy target we want to achieve for heating the house to meet passive house standard: 15 kWh/square-meter/year or 4.75 kBTU/square-foot/year. The same target exists for cooling demand for the year but since we live in a temperate climate that doesn’t require air conditioning it’s not a big concern for us.

Using the insulation specifications below our heating demand for the year to keep the house at comfortable temperature of 68-degrees Fahrenheit (20-degrees Celsius) is 8.75 kWh/square-meter/year.

Attic – 12-inches of blown-in cellulose; foam was applied to the tight corners along the wall-roof line (~R35)

Floor – 5.5-inches of fiberglass batts in the floor joist cavities and 2-inches of expanded polystyrene (EPS) board under that. (~R26)

Walls – 3.5-inches of dense pack cellulose (wet spray) in stud bays and 3.25-inches of rigid mineral wool (Roxul TopRock DD) on the exterior wall (~R28)

We had many discussions with the insulation experts, contractors, energy efficiency specialists and architects before deciding on the materials we chose.  One key learning for us was when we heard Alex Wilson speak at PG&E’s Pacific Energy Center in San Francisco.  He shared a story of a well-intentioned homeowner wanting to save energy and reduce greenhouse gas emission was horrified to learn that the spray foam product he used to insulate his house would take 60-years to payback — this is not financial payback but the time it would take his energy savings to offset the amount of greenhouse gas released into the air from the blowing agent used for his spray foam product.  So we decided to stay away from spray foam products.  You can find one of Alex Wilson’s article on insulation at Green Building Advisor.  The chart below is from that article.

Attic

Here are some before and after picture of our attic.

Before:  Very little insulation in the attic

You can see from this “before photo” that we did have some attic insulation, if only to barely cover the ceiling joist.

After:  over 12 inches of blown in cellulose

In this “after photo” you can see the measuring tag sticking up from the sea of cellulose to indicate that between 12 and 14 inches of cellulose filled  the space.

The insulation sub-contractor, Ponzini Insulation, did the cellulose insulation in the attic and in the wall cavity.  Applying blown in cellulose in the attic.  They had a big truck with special attachments to pump the cellulose through the long hose to apply the insulation.

Insulation Truck

Installer applying blown in cellulose into the attic

Floor

Crew from Santa Cruz Green Builders did the insulation and air sealing below the floor in this cozy crawlspace.  Fiberglass batts filled the 5.5-inch deep cavity between the floor joists.  Then sheets of 2-inch thick EPS board was applied under that.  The seams of the EPS boards were meticulously taped using Siga tapes.  Because the EPS board serves dual purpose of insulation and air barrier the edges of the board coming in contact with other material (wood, concrete) were foamed to prevent air leakage.

Crawl space view of the floor after completion of insulation 

Walls

Our 90-year old house did not have any wall insulation!

Before:  No insulation between stud bays

As you can see from this deconstruction photo, the space between the exterior skip sheathing (horizontal board) and the interior wall made of lath (small strips of wood) and plaster was empty.

After:  wet spray cellulose filled the wall stud bays

Wet spray insulation was applied to the open stud bays in the interior wall cavity.  This took almost one week to dry fully but it allows for visual inspection of cellulose application.  Speaking of inspection, we had Quality Insulation Inspection (QII) performed by Bright Green Strategies for the California Advanced Homes rebate program.

Mineral wool material applied to exterior sheathing

Sheets of rigid mineral wool were applied to the exterior wall.

We used TopRock DD from Roxul

Mid-Construction Tour

Join us for a mid-construction tour of Midorihaus this Saturday!

Mid-Construction tour of Midorihaus presented by Santa Cruz Green Builders
Date: April 14, 2012 (Sat)
Time: 10:00AM 

See how an old California Craftsman can be turned into a showcase green home! As the first house in Santa Cruz County to be certified as a Passive House, Midorihaus will be one of the most energy efficient houses in California. It is under construction now, so the tour will highlight the features and systems that you don’t usually get to see in a finished home. 

What is a “Passive House”? A passive house is a building in which a comfortable interior climate can be maintained with a hair dryer. This is achieved by a very well-insulated, virtually air-tight building that is primarily heated by passive solar gain and by internal gains from people, electrical equipment, etc. Energy losses are minimized. Any remaining heat demand is provided by an extremely small source. Avoidance of heat gain through shading and window orientation also helps to limit any cooling load, which is similarly minimized. A Heat Recovery Ventilator (HRV) provides a constant, balanced fresh air supply. The result is an impressive system that not only saves up to 80% of space heating costs, but also provides excellent comfort and indoor air quality. 

This tour will allow you to see examples of air sealing the entire building envelope and individual components:

• Heat Recovery Ventilator (HRV) provides constant fresh air efficiently
• Triple glazed, super sealed windows
• Structured plumbing system
• Material reuse and recycling

For more on Passive House, visit passivehouse.us OR passivehousecal.org
For more on Santa Cruz Green Builders, visit santacruzgreenbuilders.com 

 passivehouse.us
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