Category Archives for Uncategorized

Solar Access and Shading

December 14, 2010

Another good resource we learned about is the Tools Lending Library at Pacific Energy Center.  This is another free program provided by our local utility, PG&E.  Just as you would borrow books from the public library, we filled out the online request form to borrow tools from PG&E’s tools library.  Nice, isn’t?

Since we needed to get “shading analysis” for the 4 sides of the house to be used for the passive house calculation we looked for “Shading/Solar Access” types of tools in the lending library.  The search returned 7 results and we selected to borrow the SunEye by Solmetric. 

The SunEye comes with the hand-held electronic device, power cable, USB cable, PC (not Mac) software and a manual in the case. We also borrowed a Windows PC from Kurt’s brother because the companion software only runs on Windows machine and not on Macintosh — we only have Macs at home.  It took us a few tries to get the picture and the data in the form that was useful for our passive house consultant, Graham.  We found the user interface of the tool to be good once you get the hang of it by taking a few pictures.  I think the hardest part of the data transfer to the PC was getting the cable to plugged in correctly to the hand held device.  The hand-held side of the USB cable did not have an obvious “this way up” marker so you could easily plug it in the wrong way.  Once the data was transferred from the hand held to the PC a report can be generated and extracted for emailing.

Since the data from this tool is most often used for determining the optimal placement for solar panels the instructions in the manual directs the user to be facing south when taking pictures.  We actually had to stand with our backs to the wall to get the pictures we wanted.  Here’s what we did to take the pictures at each of the sides of the house:
1.  After powering on the device, press the sun icon on the lower left hand corner
2.  Press Session button and choose New in the selection window
3.  Enter data such as the session name, notes and location information
4.  Press sun icon
5.  Press Skyline then choose New in the selection window
6.  Enter panel tilt (we entered 25 degrees) and press OK
7.  Then, standing with our back to the wall, we looked in the camera image on the screen to make sure that the sun path clears the roof overhang and stood very still to make sure that the camera was level (using the built in level) and pressed snap to take the picture.

Starting at the south (back) side of the house we took the snaps.  Each time I ducked away from the fish-eye lense to make sure I was not in the picture.  We repeated steps 4 – 7 for each side of the house.  This is what the pictures looked like:

East side of the house shows lots of shading (in green) from trees.  Yellow color represents sun.

South side of the house receives lots of sun.

After Kurt took the pictures he stood still while I measured the distance from the wall to the fish-eye lens.  We took 2 pictures on the west and north sides of the house because they have protrusions. (e.g. the porch sticks out from the front of the house)  Here are the measurements:
South:  49 inches
West 1:  42 inches
West 2:  60 inches
North 1: 52 inches
North 2: 50 inches (from the bottom step of the porch)
East: 52 inches

We used the post-processing software to correct the tilt angle to 90 degrees to reflect the shading to the vertical walls.

Appliances and Kitchen Design

December 6, 2010

One of the things we learned on Friday was that appliances consume the largest portion of the electrical usage in large homes.  The pie chart based on “PG&E Survey 2009” showed that appliances consume 28%, pool 24%, HVAC (heating and cooling) 16%, lighting 15%, electronics 9% and miscellaneous 8%.  Well, we don’t have a large home, we don’t have a pool and our passive house design will greatly reduce heating needs.  Still, getting energy efficient appliances is a priority for us since we do need new appliances and the energy efficient ones have various rebates and tax credits. 

Another thing that I learned (that Kurt already knew) was that 2/3 of electricity generation in U.S. is wasted.  Of the 40.67 quadrillion BTU energy consumed to generate electricity only 13.21 quadrillion BTU, or 32%, is delivered for end use.  Again, this means 68% is wasted.  Isn’t it amazing?   This source is from U.S. Electricity Generation 2008 chart from Energy Information Administration’s Annual Energy Review 2008.  These charts were part of the workbook material used in the “Integrating Energy Efficiency and Renewables in Home Retrofits” class offered by PG&E.  Another free class offered to the public by PG&E.  To search through their class offering please visit here.

So combining these 2 pieces of information we conclude that paying attention to the energy performance of our home appliances will not only save us money on our utility bill it also can lower our carbon footprint by reducing the demand on energy generation.  Saving money and saving the planet is a win-win formula.   

OK, so we will be replacing old appliances with energy efficient ones.  But which brand and model?

We started our appliance research by visiting the Miele Gallery in San Francisco.  Why Miele?  Because that’s what Flora recommended.  Our friend, Flora, is an artist that happens to be a terrific cook and has a beautiful kitchen.  She shared with us her experience of various home remodels (about 6 previous residences) she had done and one of the things she mentioned was to go to the kitchen gallery at the design center in San Francisco and take their classes.   

On Saturday we went to the kitchen design class at the Miele Gallery.  A nice light breakfast was served before the class and Kurt got to ask questions to his heart’s content as 3 presenters covered different topics.  First, Ruth did a nice job of covering the highlights of kitchen design.  Then Rebecca covered the details of Miele appliances.  (She opened our eyes to the steam oven!)  We will be taking the master chef class at Miele in a week to learn more about this and other appliances.  Then Maureen showed examples of tiles and countertops and went into details of the different countertop materials.  Again, this class was free!  

Later we went to an appliance store in San Francisco and learned about a showroom in Brisbane that displays and hold classes for other brands such as Sub-Zero, Wolf, Thermador and Bosch.  The search for appliances will continue….

 

Combined Hydronic Space and Water Heating

December 3, 2010
Today we spent all day at the Santa Cruz Police Station.  Why?  The nice large community room at the police department was where Pacific Gas and Electric Company (PG&E) held a public class titled, “Combined Hydronic Space and Water Heating for Homes.”  Somehow we managed to register for this class that was targeted for experienced HVAC/mechanical contractors, and building performance consultants.  I liked how the instructor, Rick Chitwood of Chitwood Energy Management, Inc., taught the class with just enough explanation for us homeowners to digest the information while succinctly answering the questions from experienced people in the room.  Several people at class have taken other classes from Rick and reviewed him favorably and we definitely recommend his class.
This class offered by PG&E was open to the public and it’s *free*!  PG&E provided catered breakfast and lunch.  It was quite good too.  To see a listing of other classes offered by PG&E please visit their energy efficiency class registration site.
Towards the end of the class we did a design exercise which really drove the point of source of heat loss.  Each student did a simple heat loss calculation for an example house plan  with 1116 s.f. of conditioned floor area with windows and doors shown.  We did 6 simple heat loss calculation for ceiling, floor, walls, windows, door and air infiltration.  When we completed our calculation Kurt and I looked at each other and said, “This is why passive house makes sense — most of the heat loss is caused by air infiltration (lack of air tightness) and by windows!”
Other take away points for me were
  • Simpler is better because higher complexity triggers higher cost of installation and higher maintenance needs.
  • Tankless water heater is not what we want because it takes a long time (20 seconds) for the water to get warm, thus wasting water and they can’t take the pre-heated water from solar thermal system because the modulated power burner can’t modulate to accommodate a smaller temperature difference.
  • Huge opportunity for energy efficiency is on the table — Even in California (state with the strictest building code) one can achieve 50% reduction in energy consumption from a house that only adheres to title 24 by doing insulation effectively and further reduce the energy consumption by half by doing mechanical system effectively.
  • Generally, heating systems are over-sized for California’s mild climate.
Tomorrow we go to another PG&E class titled, “Integrating Energy Efficiency and Renewables in Home Retrofits,” in San Mateo.

Glass and Windows

December 2, 2010

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You know, sometimes you have a piece of fact stored in your head but it doesn’t mean anything until you ask why.  For example, I knew that “Glass used in windows contained lead a long time ago but today most don’t,” and “When you look at a sheet of glass from the side it looks green, like the ones at the display shelves at retail stores.”  Okay, this is basic stuff that you’ve known and observed, right?  Well, I got curious and started a dialog with my husband, Kurt, who is a photographer with physics background and has a gift of explaining science in a simple way.  Our conversation today as we were driving went something like this:

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Chie:  So, hon, I’m curious.
Kurt:  Curious about what?
Chie:  Well, I know that lead was taken out of glass because it’s dangerous.  But why did they have it in the first place?
Kurt:  You know that glass is made out of sand, right?
Chie:  Yeah…
Kurt:  Those tiny quartz pieces, sand, melt at a very high temperature.  By introducing another material into the sand it can melt at a lower temperature.
Chie:  Oh, OK, so they used lead in glass for manufacturing efficiency.
Kurt:  Right.  Not only was it efficient it was also good for light.  Lead will let light through the glass without affecting the colors.
Chie:  Really?
Kurt:  Yep.  When you look through the windows at our craftsman home you’ll see the colors in a natural state.  Lead is pretty nice for letting true colors through.
Chie:  Hmm… So what do they use in glass now?
Kurt:  Mostly soda-lime.  It has a greenish tint.  It looks green because the materials block red from coming through.  You may notice when you look through windows that people look a bit greener and less bright. 
Chie:  Why less bright?
Kurt:  Because with every air-to-glass contact you lose approximately 5% of light.
Chie:  Really?  How do you know that?
Kurt: I know it from studying physics.
Chie:  So, if there is 5% degradation of light for each air-to-glass contact then for double-paned windows it loses 20% of brightness and for triple-paned windows you lose 30%?
Kurt:  Yes, approximately.
Chie:  Wow.  You know what? I noticed those demo windows we saw had a gray tinge to them.  When we get triple paned windows with additional coating to them the house will look darker, right? I wonder if part of the “happy feeling” we get at the house is from the single pane, lead windows letting in bright natural light?
Kurt:  Hmmm…..
Later at home I brought up this topic of light going through glass losing brightness and Kurt decided to do a demonstration for me.  He grabbed one of his light meters he uses for photography and measured the brightness of the kitchen.  It was about 64.  Then he took 3 sheets of thin glass used for his 6×7 slide mounts and stacked them above the light meter so that there is air-glass-air-glass-air-glass-air, which would yield 30% less brightness.  The light reading dipped to about 45, which is 30% less than 64.  What a fun science experiment in the kitchen!
   

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Now, switching gears to windows.  As you know, we are striving for passive house certification and windows are very important for the energy performance of the house as well as the thermal comfort for occupants.  Have you noticed how much colder it feels to stand next to a window than standing next to an insulated wall on a cold night?  This is because there is a heat transfer from inside of the house where it’s warm to outside of the house where it’s cold.  With passive house windows there will be less heat escaping to the outside. The passive house windows specification is quite detailed and only few windows manufacturers in the US provide passive house windows.  In Europe today there are over 50 manufacturers, mostly small to medium businesses, offer passive house windows.  To find out more about passive house window requirements please visit the window requirement page on passipedia
From aesthetics standpoint we want our windows to have the arts and crafts look and feel with muntins.  So what are muntins?  They are those strips, wood or metal, that separates panes of glass.  With the windows requirements for passive house it’s not feasible to have windows with true muntins where there are separate glass pieces fitted into the muntins.  The look can be achieved by pasting a strip (wood or other material) on the outside pane and on the inside pane.  We wanted to see what that looks like so we visited the corporate office of Serious Materials in Sunnyvale to see a demo window unit with muntins.  When we looked closely it appears to have a “shadow” around the muntin but we were told that this is not noticeable if you simply look from a drive-by distance from the house.  (I forgot to take a picture of this today.) 
Here are some examples of craftsman style muntins –

 

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Since windows are the most expensive line item in the bill of material and have a significant impact on the performance of the house we are paying special attention.
Bottom line, we want windows that
1.     Are passive house compliant for energy efficiency
2.     Provides nice day lighting with maximum brightness and minimal color distortion
3.     Have the arts and crafts cottage look that is congruent with craftsman architecture
Oh, we want to do all of the above without breaking the bank!

Before Pictures (Nov 2010)

November 23, 2010
Here are some pictures of the house as it is today (November 2010) before renovation – 
Front of the house

This house was built in 1922 in the Craftsman style architecture.  The front door faces almost due north.  So the front of the house never is directly lit by sunlight.  This picture was taken in the afternoon with bright western light.  The large cement porch is in good shape.  The fake brick siding is curious.

Living Room
The front door opens directly into the living room.  I like how the glass on the door is highlighting the arts and craft style and giving the house more character. The natural wood used in the living room and the dining room is in arts and crafts style.
The living room has lots of space for entertaining.  The large window is facing the front towards the street and the small windows are facing east.
Dining Room
Lovely built-in “buffet” lines the western wall of the dining room.  This room has a really nice feel in the afternoon with light from the west floods the room.

Hallway
When you enter the living room you’ll see the hallway towards the south side of the house.  There are doors to 2 bedrooms on the left door to the kitchen on the right and another bedroom on the right.  Straight ahead is the bathroom.

Kitchen
Looking into the kitchen from the hallway —  The handles on the drawers are vintage 1920’s and so is the skirt under the sink.

Note the antique stove by O’Keefe & Merritt.  It still works!

The light above the stove top is charming.

Bedroom 1
This bedroom is along the east side of the house.  The morning light is pretty.

Bedroom 2
The southeast corner of the house is this bedroom 2.  Note that there is a window in the closet too.

Bedroom 3
Southwest corner of the house is bedroom 3.  An addition, bathroom and kitchenette, was built about 60 years ago.

Bathroom
There are 2 cute little windows facing the backyard from the bathroom.  Note the built-in cabinet on the right hand side behind the door.

Backyard
There are 2 productive apple trees in the large backyard.  This one has 3 or 4 different varieties of apples grafted on to this tree.

Exterior
The east, west and south sides of the house have stucco exterior.  Underneath the stucco is brown wood.

On Our Green Journey, We Discovered Passive House

November 13, 2010

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Last week, we had a chance to meet Dr. Wolfgang Feist in San Francisco, where he gave a free public lecture on Passive House at the California College of Arts.  Dr. Feist is the founder of Passivhaus Institut and is on the faculty of civil engineering at University of Innsbruck.  He was on his way to Portland, Oregon for the 5th North American Passive House Conference.  My post is a quick summary of the notes I took from that talk.  Just as a new student may not get all her facts correct, my notes below reflect my current state of enlightenment and ignorance.  OK?  Here it goes –
The Passive House is not an energy performance standard, but a concept to achieve highest thermal comfort conditions on low total costs.  The passive house buildings don’t have a particular look and or follow specific architecture.  The concept can be applied to different types and styles of buildings.  What we found impressive about passive house is the performance.  By following the passive house concept a building built in 1991 in Kranichstein, Darmstadt, Germany was able to reduce the energy consumption of the building by 80%.  The building performance was monitored from 1991 to 2010.  Amazing, isn’t?
There are 5 principles –
1.    Insulation.  Lots of insulation on the exterior walls, roof and the basement ceiling.  In the particular building shown in the case study there was 12-inches on the roof, 12-inches on the exterior walls and 10-inches on the basement ceiling.
2.    Free from thermal bridges.  Basically you want to eliminate the path that heat can flow.
3.    Air Tightness.  Warm air moving from inside to the outside of the building will deposit moisture into the building as it exits, causing problems for the building.  Air tightness of the building is achieved by applying special tapes and testing it using the blower door test.
4.    Energy gain window.  Triple pane windows allow more solar gain and less energy loss.  Note that the solar gain in the winter in central Europe is 1/5th of what’s in the Bay Area.
5.    Heat recovery ventilator. HRV is a quiet, hygienic and efficient device that provides conditioned fresh air to come into the building, providing comfort and reduced radon exposure.  The standard for HRV, by the way, is different between Europe and US.
Today all European countries have passive house demonstration projects.  Passive house demonstration projects are also found in other countries such as Russia, Japan, China, Korea, South Africa, Australia, Antarctica, Chile, Canada and United States.
To learn more about Passive House please visit Passive House Institute US and also the Passipedia site, where passive house information is available to the public and member postings are reviewed by scientists.  

Search For Land… Got A House

October 21, 2010

One of the criteria for our green, sustainable home was walkability.  This means being able to walk-to or at least bike-to grocery stores, farmers market, coffee shops, restaurants and entertainment.  Another criteria was good southern sun exposure for solar applications and growing a nice edible garden.  The desire for good air quality and low noise level meant staying away from major streets with high traffic.  There were few other items on our “selection filter” like buildable lot and reasonable cost.   Being the analytical couple that we are we had a spreadsheet with weighted scoring with all of our selection criteria with formulas that summarized numerical value for each of the place we considered.  At times sticking to our agreed upon filters was tough.  We felt impatient and just wanted to begin our journey of building our green home.  It took us over 2 years of serious searching to get a place for our green home project.

In 2008 we were looking for an urban infill lot within the city limits of Santa Cruz.  We were thinking of new construction with perhaps ultra modern design.  With the declining real estate market we thought we’d be able to get a plot of land at a good price.  Well, the people who owned such properties apparently were not in any rush and wanted much more money than we offered.  We looked at MLS listings every few days.  We rode our bikes around town to identify unbuilt lots and looked up the owners info at the county tax assessor’s office and sent them letters.  No sale.  The most exciting thing was going through 3 counter offers on 6098 sq.ft. lot that fizzled when we couldn’t agree on price.

In 2009 we expanded our search to include fixer-uppers and tear-down homes.  We were fortunate to be working with Gary, our real estate broker who also is an attorney and builder.  He gave us valuable remodeling insights as we looked at various properties.  In fact, he opened our eyes to the value of renovating an older building when we bid on the 109-years old Victorian house that was ready for gutting. We lost that bid but gained new perspective.

In 2010 we started the year by bidding on a foreclosure house that was in move-in condition.  The house passed our selection criteria and our idea was to “green it” with additional insulation, water efficiency and energy efficiency.  Though we put in a strong offer we didn’t get it.  We learned that even in this down economy when a good property shows up on the market the competition is fierce.  So we lost that bid and continued searching.  Few months later we again lost the bid on another house that was in ready to move in condition.  In retrospect we are so grateful that we did not get any of those because what we got is a gem.

In late July we saw a house come on the market that looked interesting — a 1922 Craftsman style home that had signs of deferred maintenance and good bones.  It wasn’t love at first sight but it fit our criteria and we didn’t find anything horribly wrong with it so we put in a strong bid, fully expecting a counter offer and bidding war.  Then we got the call from Gary that evening saying our offer was accepted.  We were stunned… and happy.  As we learned more about the house, neighborhood and architecture we felt happier and happier.  More on that later.

So we started our green home  journey with the idea of building something new that would be green but instead we will be doing a project that is much greener.  We are reusing the parts of the house that was built 88 years ago, such as framing, foundation, roof, nice woodwork and built-in features.  What could be greener than that?

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