kimchi & kraut

Passive House + Zero Net Energy + Permaculture Yard

Tag Archives: Net Zero

Solar on the Roof

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After deciding to pursue a combination of Passive House and The Pretty Good House concepts, which entail careful planning and attention to air sealing, along with a significant amount of insulation, we knew we could have a shot at Net Zero, or Zero Net Energy (ZNE) — meaning we could potentially produce as much energy as we use by utilizing solar panels on the roof.

To find an installer in our area, we utilized the website Energy Sage. In addition to useful articles and information about solar, they also work with installers who can provide consumers with competitive bids. It didn’t happen overnight, but in about a week or two, we ended up with 3-4 bids before deciding to go with Rethink Electric in Geneva, Illinois.

laying out the solar panels pre-install

The guys from Rethink staging the panels on the garage roof.

 

 

The System

Based on the suggestions from Energy Sage and Rethink, we ended up going with the following system:

  • 2.915 kW DC System
  • 4,059 kWh of system production
  • 11 Canadian Solar panels
  • 265W Module Enphase M250 (Microinverter)
  • Also includes web-based monitoring of the system’s production

In theory, this system could produce more energy than we use (it’s just my wife, my daughter, and myself who will be living in the house), particularly if we stick to all LED lighting, use Energy Star rated appliances, the heat pump water heater works as advertised, and we’re careful about avoiding using electricity when it’s unnecessary (e.g. turning off lights after leaving a room, or trying to address phantom loads).

Anthony putting self-adhering gasket over solar conduit penetration

Anthony, from Rethink, air sealing the penetration through the Intello, our ceiling air barrier,  with a Tescon Vana – Roflex gasket before sending his 3/4″ conduit into the attic.

Based on other projects I’ve read about, even homes initially built to the ZNE standard sometimes fail, in terms of overall performance, based on actual occupant behavior, so only time will really tell what impact our solar array will have on our utility bills. It looks like worst case scenario would be needing to add 4-6 more panels to get to ZNE or even carbon positive.

conduit for solar in the attic before gasket

Anthony’s conduit entering the attic, sealed with a gasket from below.

Installation by Rethink went really well, and they were happy to work with me on properly air sealing the conduit that runs from the basement at the main panel before going up into the attic, where it eventually terminates on the roof when connected to the panels.

conduit for solar in the attic after gasket

3/4″ conduit sealed for a second time on the attic side of the Intello.

 

solar mounting system being installed

The guys setting up the racking system for the panels.

 

Rethink guys on the roof

Anthony, Dan, and Cherif completing the install on the roof of the house.

 

close up of solar panels being installed

The low profile racking system has a very sleek look.

Marking another big leap in the progress of the build:

solar panels on roof

The view of our 11 solar panels from our neighbor’s driveway.

 

solar panels installed on the roof.jpg

Another view of the solar panels installed on the roof.

It was only after the installation that I realized what’s wrong with the following picture:

solar on:off against Zip sheathing #2

My screw up.

I was so worried about getting the air sealing details right on the interior, from the main floor to the attic, I completely forgot to let Anthony know about extending out his disconnect box 6″ to what will be our finished surface (once two layers of Roxul and two layers of 1×4 furring strips, along with cedar siding are installed). The day after they installed, I came walking around the corner of the house, saw this, and literally slapped my forehead (while spitting out a few choice expletives), as I realized my screw up.

Thankfully, Anthony was able to come back out and make the necessary adjustment:

corrected solar on:off

 

 

The Cost

Here’s the cost breakdown on our system (if trends continue, a similar system should be less expensive in the future):

$12,519.50  Initial Investment
$(-3,755.85)  Federal Tax Credit (ITC) 30%
$8,763.65  Net Cost of First Year
$(-3,816.00)  Solar Renewable Energy Credits (SREC’s)
$4,947.65  Net Cost After All Incentives

It will be interesting to follow the performance of the solar panels over the course of a calendar year or two, just to find out exactly how well they perform. I’ll come back here and post monthly utility statements, noting output of the panels and our use, to give people a better sense of actual performance — hopefully this will help others in the planning stages of their own project to decide if solar (and how much of it) is right for them.

“How did I get here?…”

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So Why Build an Eco-friendly “Green” Home Anyway?

In the summer my wife and I teach a class together, called Excel 2, which is one small component of a larger, overall Excel Program (my wife is a high school Social Studies teacher).

Typically, Excel students come from first-generation immigrant families. They are college-bound students who have exhibited great potential, but who are in need of some encouragement, particularly in regards to taking Advanced Placement (AP) courses (huffington post). For most of our students, they will be the first ones in their family to attend college, so it is understandably an intimidating prospect in any number of ways.

The course itself is three weeks in the summer session, its focus on developing reading and writing skills by utilizing non-fiction reading assignments. We emphasize the importance of correct spelling, proper grammar usage, and attention to detail by requiring multiple revisions to several thesis paragraphs, which are themselves based mostly on college-level reading assignments.

You can imagine how well this goes over with incoming high school sophomores and juniors — especially in summer. We’ve tried to overcome this dilemma (how to motivate young high school students to tackle a course based on rigor when many of their friends are out enjoying summer break) by delving into topics they are intimately familiar with, but hopefully in ways they have not yet confronted.

IMG_9702

Some of our Excel students with my wife, Anita: (front row) Aubrey and Imani, (back row) Eduardo, Anita, Cecelia, and Karen. 

As a whole, 50% of the students attending Palatine High School qualify for free and reduced lunch. Not surprisingly, then, the Excel students face some unique, if not daunting challenges, both in and out of the classroom. In addition to the normal stresses associated with being a teenager, many of them deal with balancing school work with long work hours at low-paying jobs (helping their families make ends meet), social pressures to stray down the wrong path (in any number of ways), and even (most heart-breaking of all) confronting what researchers term being food insecure — in plain English, not always knowing when or where they will get their next meal.

We present the class to the students as an opportunity to test themselves, to really see where they are, currently, in terms of a whole host of skills. The main goal of the Excel 2 program, therefore, is to really challenge their abilities, not just in terms of reading and writing skills, but also soft skills such as interpersonal communication, the importance of body language, time management, and self-discipline.

Essentially, we try to give them a college-level course experience, hoping it better prepares them for the eventual reality. In other words, we’d rather they struggle in high school with us than have it happen when away from home for the first time, off on their own, at college  (atlantic)  (newsweek)  (washington post).

Here’s an example of our ever-changing syllabus:  Excel 2 – 2015

As you can see from the reading assignments, we encourage our students to start asking questions about everyday things they may be taking for granted. We hope this sharpens their critical thinking skills, but we also hope it encourages them to be more active participants in their lives, rather than just sleepwalking through their days as passive consumers.

Consequently, when it came time for us to find a new place to live, we saw it as a good opportunity to practice what we preach:

  • What exactly do you want from a new house?
  • If you’re going to buy a house (and you’re lucky enough to even contemplate doing so), what should it look like? A condo? A townhouse? Or a single-family residence?
  • In which neighborhood are you going to buy?
  • How many square feet do you want (or need)? How many bedrooms? Do you want (or need) a formal living room or dining room? Do you want (or need) a basement?
  • What architectural style appeals to you?
  • How are you going to furnish the interior?
  • Should you care about indoor air quality (IAQ)? And if you do, how do you protect it or improve it?
  • What do you want in your walls and attic for insulation? How much do you need?
  • How much will utilities cost? Are there cost-effective ways to reduce those costs?
  • Are renewables — solar, wind, or geothermal — worth considering? How long is the payback period?
  • Do you want your house to be environmentally friendly — and what does that mean anyway?

Instead of moving into the typical, leaky, not very environmentally friendly suburban condo, townhome, or house (we were leaving behind the latter), we thought it would be more interesting to see just how “green” we could make our next house.

Because we wanted a yard to do plenty of landscaping and gardening, we narrowed the choices down to a single-family house. And, instead of tackling the challenges that come with a retrofit, we decided to try building new.

Much like hearing Jonathan Ive talk about an Apple keyboard, we appreciated the detail required to meet the certified Passive House standard. At the time (summer 2014), this seemed like the way to go.

After the experience we had with our original builder (2015), and then subsequently trying to learn as much as possible about the Passive House standard, in addition to discovering the Pretty Good House concept along the way, our house plans have evolved into a kind of 3-headed hybrid: Passive House science + Pretty Good House + Net Zero (Zero Net Energy: ZNE).

The goal of all three is to dramatically reduce the energy consumption of our house as much as possible (especially our dependence on the energy grid). We also want to do a significant amount of planting and growing in our yard, mostly xeric plants that require little additional watering, in order to combine house and yard into an eco-friendly system of sorts.

Our last home (approx. 2800 sq. ft.) was a fairly typical suburban tract house. It had builder-grade windows and doors (most of which had to be replaced after just a few years), very little insulation in the walls (the switch for the back porch light would actually ice up when temperatures fell below 20° F), and it had a great deal of under-utilized space (e.g. a two-story foyer, a formal living room and dining room, and a fourth bedroom, all of which saw little use).

With our new home (just over 1500 sq. ft. of living space), we’re trying to turn all of this on its head so we end up with something we really want and will enjoy. To paraphrase Kevin McCloud: ‘maybe it’s better to have a little bit of something special than a lot of something mediocre’.

An oft-quoted statistic (1)­ suggests a significant amount of our greenhouse gas emissions can be attributed to our structures (typically the figure is in the 40-50% range) — including residential, commercial, industrial, and governmental — so maybe change really does begin at home (SA) (greenbelt movement).

 

(1) According to a recent Fine Homebuilding article, “Better Than Average”, by Brian Pontolilo: “It’s not clear how much our homes contribute to greenhouse-gas emissions and to climate change. The most recent data available from the Department of Energy is from 2009-2010. Outdated as it is, this data indicates that residential buildings contribute around 20% of total U.S. greenhouse-gas emissions. This includes fossil fuels used on-site (e.g. natural gas for cooking and heating) as well as electricity.” (September, 2016 issue, p. 64)

 

And if you’re wondering about the quote in the title of this blog entry, it’s a line from this song: