Two Vermont Schools gear up for Solar Decathlon 2013

As a dedicated reader of the TruexCullins Blog, you must know we are big fans of the Solar Decathlon, the biennial competition sponsored by the U.S. Department of Energy that pits 20 collegiate teams against each other to design and build a fully self-sufficient solar powered home.  After all, we wrote about the event here, here, here, here, and, oh... here.

Last year was the fifth Solar Decathlon competition since its inaugural run in 2002.  And last year a Vermont school was admitted for the first time: Middlebury College, a small liberal arts school that has no professional architecture program to speak of.  In fact, since the Solar Decathlon began 10 years ago, Middlebury was the first liberal arts college to ever enter alone, without teaming up with a larger architecture or engineering University program.  Despite this underdog status, Middlebury managed to come in an impressive fourth place overall. And of the 10 competitions, they scored first in 3 of them: Market Appeal; Communications; and Home Entertainment (which was partially based on a dinner party featuring a home-cooked Vermont meal).

The plans are being drawn up now for the next Solar Decathlon, being held October 3-13, 2013.  For the first time, the event is moving away from the National Mall and heading west, where it will make a new home in California, at the Orange County Great Park in Irvine, just south of Los Angeles.

The 20 student teams chosen to participate have just been announced, and we are happy to see that two Vermont schools will be competing this time.  Middlebury College will be returning to build on their successes from last year, and they will be joined by Norwich University. Norwich has a bachelor’s and Master’s program in Architecture, and we know they have been planning for the Solar Decathlon for a while now.

It will be exciting to see Vermont so well represented in the field of renewables on this national stage, and we wish the best of luck to both schools!

Fighting Climate Change in Vermont, One Net-Zero House at a Time

We are in the middle of one of the warmest winters in memory, with a noticeable lack of snow. Many are still cleaning up from Tropical Storm Irene, which hit a state not used to dealing with hurricanes and flash floods. As these examples of extreme weather events grow more common, fewer people are doubting that climate change is affecting Vermont in very real, measurable ways.

A new exhibit is now open at the ECHO Lake Aquarium and Science Center that explores the impact of climate change in New England. Seasons of Change: Global Warming in Your Backyard is an interactive travelling exhibit that will be at ECHO until March 25, 2012.

You may think you know what to expect with global warming, but this exhibit will open your eyes to much more. Developed by members of the New England Science Center Collaborative and Brown University, Seasons of Change looks at how climate change is affecting things in Vermont like invasive species, foliage, maple products, fishing and more.

This is a daunting challenge, but we are rising up to meet it.

This week we will be attending the Better Buildings by Design conference, an annual event hosted by Efficiency Vermont that brings together architects, engineers and builders for 2 full days of interactive learning about building efficiency. Global warming is often thought of as the result of pollution from cars and power plants, but buildings are actually an equal culprit. Nationwide, buildings are responsible for one third of all greenhouse gas emissions, equal to that of transportation and industry.

At Truexcullins, we are working for a better climate future by designing net-zero energy buildings. These buildings produce as much energy as they use. By intelligently managing the energy demands and eliminating the need for fossil fuels, we can reduce greenhouse gas emissions and slow the spread of global warming.

One of our recent green homes will be recognized with an award from Efficiency Vermont at this week's conference. This net-zero energy home in Calais, Vermont will be receiving the award for Best of the Best in Energy-Efficient Residential New Construction. TruexCullins Principal Lee Grutchfield was the architect on the project, with general contractor Hobie Guion and energy consultant Andy Shapiro of Energy Balance, Inc.

 

Congratulations to the entire project team!  We have more of these projects in the works, and we look forward to working with all of our colleagues and consultants to develop net-zero energy buildings that help to solve our climate challenges. 

Solar Decathlon Review, day 3: Our Favorites

This Sunday, October 2nd is the final day for public viewing of the 19 student-built solar-powered homes of the Solar Decathlon on the National Mall.  The excitement is building as the points are adding up and a winner is coming into focus.  Tomorrow, Saturday Oct 1st, the winner will be announced, the team that has accrued the most points across the 10 categories in fields such as architecture, engineering, energy and affordability.

Many of the houses incorporate some of the technologies and green design strategies that I described in yesterday’s post, but the best houses are the ones that bring it all together beautifully.  Here are 3 of our favorites:

LIVING LIGHT by the University of Tennessee

This house is based on the cantilever barns of Southern Appalachia, with an open plan anchored by a dense core at each end.  But the real intelligence is in the envelope.

The all-glass north and south elevations consist of a 16” thick double-façade system, with a fixed plane of glass on the exterior, alternating fixed glass and full-height casement windows on the interior, and internal blinds.  In the winter, the air space within the south-facing façade collects heat that is directed to an ERV, supplying the home with preheated air.  In the summer months, the system works in reverse, drawing fresh air from the north façade by the ERV and pre-cooling it before it hits the ductless mini-split units.  Exhaust air is directed through the south façade to cool the cavity and reduce heat gain.

Energy is generated from a 10.9 kW rooftop array of cylindrical PV panels.  Look closely: those are cylindrical tubes that make up the canopy over the south façade.  Thin-film PVs are wrapped around these tubes, collecting sunlight from any angle.  There is no need to worry about the correct angle of the panels here, since the cylinders absorb sunlight from all directions.

You can get more info on the University of Tennessee solar house from the project website, livinglightutk.com, including some great detailed descriptions and explanations of the smart façade, roof top array, and more, at: livinglightutk.com/smartsystems/

WATERSHED by the University of Maryland

This house is all about the conservation and management of our water resources.  Coming from the Chesapeake Bay area, the students of the University of Maryland drew inspiration from the 64,000 square mile Chesapeake Bay watershed and have designed a house that addresses the storm water issues that threaten this fragile ecosystem.

The form of the house is defined by two rectangular modules with a split-butterfly roof.  A 9.2 kW solar PV array covers one side, and a green roof tops the other.  Rainwater is captured from the roof and directed to a series of captured wetlands, where the water is naturally filtered by plants until it can be pumped out for reuse as irrigation water.  Greywater from the shower is also directed to the constructed wetlands for reuse.

 

 

Finishes include thermo-treated exterior wood siding of poplar and ash, and recycled concrete countertops.

This is the 4th time the University of Maryland has competed in the Solar Decathlon, and their experience is paying off: as of this writing, they are currently in 1st place.

More information on WaterShed can be found at the University of Maryland project website, 2011.solarteam.org.










 

SELF RELIANCE by Middlebury College

This is the first year that a Vermont school is competing in the Solar Decathlon, and as a Vermont architect, I’m happy to say that Middlebury College has put up an impressive first showing.

The Middlebury house, dubbed Self Reliance, is a modern take on the traditional Vermont farmhouse.  It hits so many of the themes we all associate with the Vermont lifestyle: natural materials, sustainable food production, and family-friendly spaces.

Wood floors were harvested from Sugar Maple trees on the Middlebury campus.   The kitchen floor and island countertop is made of local Vermont slate.  And the children’s bedroom furniture is made by our friend Lincoln Brown of Modern Vermont.

While most of the other houses on the Mall covered every possible surface with spray foam insulation, Middlebury came out firmly against the stuff and instead went with a completely cellulose-insulated envelope. They explained their approach this way:  “Conventional insulations such as fiberglass or spray-in foam contain particles hazardous to all forms of life. They are also non-biodegradable and require tremendous amounts of oil and energy to process.  On the other hand … Cellulose insulation is safe, low-energy, cheap, and – most importantly – natural.”

Self Reliance is focused on personal, sustainable food production.  A greenhouse wall in the kitchen is not much more than a system of shelves for growing potted vegetables and herbs, but it is centrally located and promotes home-grown healthy eating. By making this such a prominent feature of the house, the students are trying to highlight the connection between local food production and energy use.

This is a very family-friendly house, designed for a family of four, with a division of public and private spaces.  Most of the other schools seem to struggle with the space constraints of the competition, designing homes under 1,000 square feet with murphy beds, movable walls, and multi-purpose spaces.  Many don’t even have real bedrooms.  The Middlebury house actually has TWO bedrooms, and a play loft accessible by a metal ladder.

Middlebury is doing very well for this being their first time in the Solar Decathlon.  They scored 4th in the prominent Architecture category, and came in 1st place for “Home Entertainment”.  This is one of those categories that aims to show that these are real, livable homes, so the students had to throw a movie night and 2 dinner parties.  They probably won due to the delicious localvore meal they prepared, which their guests praised as being very “Vermonty”.

On Wednesday, Metropolis Magazine called Self-Reliance one of “the two most striking projects at the Decathlon”.  They described it as “a warm and straightforward modern version of a traditional New England home that beautifully uses native Vermont materials.”

You can read more about Self Reliance on the Middlebury College project website, solardecathlon.middlebury.edu

Congratulations to the Middlebury team and to all the teams at the Solar Decathlon, and good luck tomorrow as the grand prize winner is announced!

Solar Decathlon Review, day 2: Products and Process

There are a wide range of projects at the Solar Decathlon, where schools from 13 U.S. States and 5 countries are each building their own version of the ideal net-zero energy solar powered home.

The houses are built for different climates, cultures, and user groups, depending on the location and type of school competing.  But one thing is common for all the teams:  they have spent a lot of their own energy researching the best products and developing new design strategies for solar powered buildings.  I go to the Solar Decathlon to discover what the future holds, and I found plenty of new green products and design features.  Here are my Top Ten:

1.   Bi-facial solar panels:   These solar panels collect energy from both sides, collecting direct sunlight from above as well as reflected light from below.  It is one of the newest types of solar panels to hit the market, generating up to 30% more power.

The Solar Homestead by Appalachian State University made the most of this technology, with a huge outdoor space covered with a canopy of bi-facial solar panels set within a beautiful wood structure.  Every team distributed “take-aways” or brochures to those people waiting in line to tour the houses, and Appalachian State had a real clever way of tying their marketing materials into the design of the solar array.  Their brochure folded up into an origami hat, with a reflective silver exterior.  As crowds of people walked beneath the bi-facial solar canopy, light was reflected off their silver heads back up to the panels above, generating more energy, potentially pushing Appalachian State over the finish line.

 

2.   Smart home controls:  It became apparent pretty quickly what really set this competition apart from previous years: the iPad.  Home automation systems were all the rage this year, with iPads, smart phones, HDTVs, and even a hacked Xbox Kinect providing a greater level of control of all the home’s systems.  Many of the teams wrote their own apps, controlling everything from the lights to the heating and cooling systems.  The SciArc/CalTech team developed a system that provided real-time energy use and controlled the shades.  The University of Illinois had a very impressive high-density display that even told you which windows were open.

3.   ERVs:  When you live in a very tight super-insulated home, mechanical ventilation becomes necessary to provide enough fresh air to all the habitable spaces.  Energy Recovery Ventilators take the heat energy from the exhaust air (in the winter) and transfers it to the incoming fresh air. (or the reverse in summer)  Most homes in the Solar Decathlon utilized an ERV, instead of the alternative: an HRV, or Heat Recovery Ventilator.  An HRV also exchanges heat energy between incoming and outgoing air streams, but an ERV has the added benefit of transferring moisture in the air.  By reducing the humidity level of the incoming air on this hot and humid September week in Washington, less demand was placed on the air conditioning systems, saving more energy. 

4.    Liquid dessicant dehumidification:  A couple of the houses sported decorative indoor water fountains that were more than just pretty pieces of art.  The University of Maryland developed an innovative Liquid Dessicant Waterfall system (patent pending) that uses a high-saline solution to absorb humidity from the air, reducing the load on the mini-split air conditioners.  The transfer of moisture happens vertically within this glass box and is displayed prominently as a design feature in the room.

5.   Home-grown food:  Many of the schools explored the true meaning of sustainability by providing a way for their occupants to grow and harvest their own food.  Normally this wouldn’t play into the energy-focused categories of the Solar Decathlon, but this year’s competition included a Home Entertainment category, in which each team had to throw 2 dinner parties for their neighbors.  This was a chance for the teams to show off their home-grown foods.

The New York team oriented its kitchen directly opposite large glass doors that open onto the outdoor roof garden, for easy picking at mealtime. The garden produces about 190 pounds of vegetables, about half of the resident’s annual consumption.

The Middlebury College house features a green wall in the kitchen and outdoor planters for growing vegetables and herbs.  In lieu of a brochure, visitors to the house received a packet of seeds.

The University of Maryland used composted waste as nutrients for food production in their vegetable and vertical gardens.

6.  Phase change materials:  In order to minimize unwanted solar gain, phase change materials [PCMs] are used to store heat energy and slowly release it at night. At the Solar Homestead by Appalachian State University, a modern Trombe wall consists of a plant oil mixture contained in a series of vertical fins.  In the evening, energy stored in these PCMs is released as the wax resolidifies and transfers its heat to the house.

In the mechanical room, phase change materials are also used to capture and store energy from a solar thermal skylight.  The hot water-glycol mix from the solar thermal system runs through tanks of paraffin wax, which stores about 50,000 BTUs of energy.  This setup replaces a traditional water heater.

7.   Adaptable furniture:  By the nature of the competition, smaller houses have an advantage because they contain less cubic space to heat and cool.  But each house has to include the required spaces and amenities.  As a result, the students tend to come up with some clever space-saving solutions. We saw sliding walls, pivoting panels, and adaptable furniture.

SciArc and CalTech designed a family of upholstered lounge seating that nests like a puzzle into the wall when not in use.  The University of Tennessee house featured a retractable bed that disappeared up into the living room wall cabinet.  And the University of Maryland house had a dining table that folded open into a bed.

8.   Micro-inverters:  With a solar PV array, an inverter is needed to convert the DC-current that is produced by the solar panels into the standard AC-current that is used in the home. Typically, a single inverter is used with a whole array of panels, but if one of the panels is shaded or dirty, its limited output will be reflected in the whole system.  Micro inverters are used so that each panel can operate at its maximum capacity.  Many of the schools used micro inverters, with one connected to every individual panel.  In this setup, each panel operates at its own peak level.

9.  Water Reuse:  The collection, treatment, and reuse of rainwater and greywater is an important aspect of many of the houses.

The outdoor planters of the SciArc / CalTech house are connected to the greywater system and are automatically watered based on weather forecast data.  WaterShed by the University of Maryland is designed with two sloping roofs that direct rainwater to a constructed wetland, where it is stored and filtered for reuse for irrigation.

10. PV solar shading:  Rather than being content to apply their solar panels to their roof, some of the teams elected to hold them off the house, creating secondary structures.  The University of Tennessee and Team Massachusetts  both created solar canopies in front of their buildings, which provided a shaded area outside, and cut down on direct solar gain hitting the windows of the front façade.  By removing the PV panels from direct contact with the roof, this also allows for ventilation on all sides.  This keeps the panels cooler and lets them operate more efficiently.

The best houses in the Solar Decathlon incorporated many of these products and features, and did so with consistency, harmony, and beauty.

There are only 2 days left until the final winner is announced.  To learn more about all the teams and follow the current rankings, go to solardecathlon.gov.

Tomorrow I’ll wrap up my review of the Solar Decathlon with a shorter list of my overall favorites.

Solar Decathlon Review, day 1: Market Appeal

 

I just returned from the Solar Decathlon in Washington DC, where 19 teams of college and university students are competing to design and build the best energy-efficient house powered by the sun.  Each school has constructed their home on the mall, a net-zero building between 600 and 1,000 square feet.

This is the fifth US Department of Energy Solar Decathlon, and there are a few noticeable differences since it first started in 2002.  The biggest change is the location.  Previously located on the main stretch of the National Mall, under the shadow of the Washington Monument, the event this year was relocated to a slightly more remote location, on the edge of the Tidal Basin near the FDR Memorial.  (The Park Service claimed the construction vehicles were destroying the grass. Jeesh!)  But being off the beaten path didn’t seem to do anything to keep the crowds away, as long lines began forming by early afternoon on this overcast Saturday.

The other major changes to this year’s Solar Decathlon have to do with the structure of the competition itself.  Each house is measured or judged in the following 10 categories:

• Architecture
• Market Appeal
• Engineering
• Communications
• Affordability
• Comfort Zone
• Hot Water
• Appliances
• Home Entertainment
• Energy Balance 

It seems the Department of Energy has an agenda this year to spread the message that going ‘green’ is affordable and within reach, so they’ve tweaked the rules a bit to appeal to the skeptical American homeowner.  

One of the students on site explained to me that at the 2009 Solar Decathlon, the winning German team spent $1.2 million on their house, covering every possible surface with PVs to maximize their energy production.   Up until now, students were rewarded for producing surplus energy beyond net-zero.  Each team was given an electric car to drive around town on the surplus energy they produced, racking up miles and points.

In response to the excessive spending, a few changes were made that alter the focus of the event.  First off, a new category was added this year: Affordability.

Each house is assessed by a construction estimator, and if the total cost comes in below $250,000, the team is awarded the full 100 points in that category.  As the cost goes up, the number of points are reduced, down to zero points awarded for a cost of over $600,000.

In addition, there are no longer any rewards for producing surplus energy beyond that which the houses consume.  At previous Decathlons, the houses were off-the-grid, so each home relied on a large bank of batteries to store extra energy.  This year, there were no batteries in sight.  A miniature utility grid was constructed on site, and no additional points were awarded for energy produced beyond net-zero.

Closely related to affordability is “Market Appeal”.  In this category, each team determines who their target market is, and their house is judged on its livability, constructability, and “curb appeal”. 

One of the most often asked questions is where the house will be when the competition ends.  One of the teams chose to leverage the affordability aspect and design their house for a family in need through Habitat for Humanity.  The Empowerhouse is a joint venture of Parsons the New School for Design and Stevens Institute of Technology.

Another school, the University of Illinois at Urbana-Champaign, has designed their house as a rapid-response emergency solution for areas affected by natural disasters.  The Re-home can be deployed quickly as an affordable, self-powered source of shelter for those left homeless.

The most unique approach I found to market appeal was from the City College of New York.  Their Solar Roofpod is designed to be placed atop an existing mid-rise urban building, taking advantage of underutilized roof space and feeding energy to its host building below.  

But enough about affordability and market appeal.  Let’s talk about what we really look for in the Solar Decathlon:  technological innovation, creative solutions, and new products that have been exhaustively researched and fully vetted by passionate students out to change the world.  Big solutions to the big problem of global climate change.

Tomorrow I will share some of these new products and creative strategies that I found at the Solar Decathlon for making a better net-zero solar powered home.

Lead-up to the Solar Decathlon, Part 2

At the Solar Decathlon, which opens this Friday on the national mall, 19 teams of college and university students will be competing in 10 categories to see who can design, build and operate the most energy-efficient and beautifully designed solar-powered home.

What makes the Solar Decathlon so successful is that it is a competition between teams of college and university students.  The fact that it is a competition is a great motivator to maintain the level of energy needed for a project that takes about 2 years to develop and hundreds of thousands of dollars in fundraising. Once on site, the competition aspect adds a level of excitement that unfolds a little bit each day as points are awarded and a winner emerges.

That these houses are designed and built by college students is key to the role of the Solar Decathlon as a forward-looking research project on emerging green design and construction methods.  (It's also a great way to engage the public to be able to connect with your alma mater, or to the school in your community.)

The Solar Decathlon is more than a showcase of current technologies... it is more than a home show.  After a long process of research, design, development, funding and construction, the competing teams often discover new solutions and develop new building methods for creating better, more comfortable and energy efficient homes.

Past Solar Decathlons have led to patents on new building products, and past Solar Decathlon teams have gone on to create architecture firms to continue their work that they started here.

This year, Middlebury College is competing as the first Vermont school to enter the Solar Decathlon and the first ever liberal arts college to enter the competition alone.  From the looks of things, they are going to face some stiff competition.

There are a few teams that I will be especially interested in when I’m on the Mall this weekend. One of these is the University of Tennessee, which has designed a house they call “Living Light”.  As you can see in their video walkthrough, the Living Light has a double-glazed façade with an inner air space that is used to help heat and cool the interior.  The house’s PV modules are cylindrical, something I haven’t seen before, designed to absorb more of the sun’s rays.

What makes the event so interesting is the range of very different approaches that each team takes.  Some schools opt to fit up a conventional home with solar panels to show that these technologies are within reach for the average homeowner.  Other teams choose to push the envelope and think totally out-of-the-box, disregarding cost or “market appeal”, in favor of innovation and invention.

One team in this latter category this year is the joint effort of SciArc and CalTech.  Their house – CHIP – is forward-leaning, futuristic and puffy. (yes, puffy.)   In this house, you use an iPad app to control the home’s systems and an Xbox Kinect to turn off the lights.  

Other schools competing this year include Purdue, the City College of New York, UMass Lowell, Ohio State, and Team Florida.  International teams are coming from New Zealand, Canada, Belgium, and China.

At past Solar Decathlons, students have built houses with soy-based SIPs, reclaimed shipping containers, and polycarbonate facades filled with translucent aerogel. Homes reduced their energy consumption with radiant cooling panels, phase-change materials, and ERVs with silica-gel rotary wheels. Landscapes were irrigated with greywater systems, facades were clad with copper sheets, and electric cars zipped around town on the surplus energy that was harvested from the sun.

In fact, the houses contained so many innovative features and materials that they were often criticized for being too expensive for the average homeowner. So this year, the list of 10 categories that comprise the Decathlon was modified slightly to include a new one: affordability.

In addition to displaying financial solvency, the students are judged on architectural design, engineering, and energy balance.  They have to boil water, run the dishwasher, and throw a movie night on the wide-screen TV.

It’s all an effort to show that these are real houses ready for widespread consumption.

Lead-up to the Solar Decathlon, Part 1

Posted by Matthew Bushey

This week marks the much-anticipated kickoff of the fifth U.S. Department of Energy Solar Decathlon competition, held on the National Mall in Washington D.C.  The event pits 20 teams of college students against each other to see who can design, build and operate the most energy-efficient, comfortable, healthy, affordable and beautiful solar-powered home.

From Sept 23^rd until Oct 2^nd, 19 homes will be built on the Mall and opened to the public for tours (the University of Hawaii dropped out). These are real homes, typically 800 to 1,000 square feet, that draw all of their energy from the sun.

I attended the first Solar Decathlon in 2002, and went again to the second one in 2005, to see firsthand the innovative designs and new technologies that these kids had come up with. This year, I will be returning to D.C. once again to see the Solar Decathlon, with a renewed sense of urgency, interest, and excitement.

Three weeks ago, Vermont was rocked by massive floods that caused widespread damage and attracted national attention.  It seemed we had just recovered from the spring floods and were taken by surprise by Tropical Storm Irene.  Elsewhere in the country, droughts are lasting for months on end and wildfires are burning at an unprecedented rate.  They say this is the ‘new normal’.  Warmer oceans are feeding stronger hurricanes, and the changing climate is leading to destructive weather patterns that threaten all of us.  With each passing year it becomes more evident that we need to speed up our efforts to power our buildings from renewable energy sources that decrease our greenhouse gas emissions.

The Solar Decathlon is showing the way.  For a quick description of the event, check out this Welcome and Overview video by the DOE:

This year, a Vermont school is participating in the Solar Decathlon for the first time. Middlebury College is on the Mall right now, assembling their first Solar Decathlon house, a 2-bedroom, 1,000 square foot home they call “Self-Reliance”. Unlike many of their competitors, Middlebury College does not have an accredited architecture program. In fact, Middlebury is the first ever liberal arts college to enter the Solar Decathlon alone. Its team consists of over 85 students from a variety of disciplines, working on the design, construction, and communication of Self Reliance.

I am really looking forward to seeing this house firsthand during the competition on the National Mall.  Check it out here: 

For more information on the Solar Decathlon, visit the official website at www.solardecathlon.gov. You can also follow the events on the solar decathlon facebook page, or on this here TruexCullins blog for more reports from a Vermonter’s perspective.

Passive House design comes to Vermont

Posted by Rolf Kielman, AIA, LEED AP

The Passive House: it sounds like some kind of strategic mind game for buildings. In actuality, this is a very positive development for designing better buildings.

In the quest for more knowledge about these passive houses, I spent last weekend with Marc Rosenbaum at the Yestermorrow Design-Build School. The course he was teaching dealt with the comprehensive process involved in the design of Passive House. The Passive House is a rigorous process for ensuring dramatically improved energy performance. This process has been stringently refined by (who else?) German design professionals. It is applicable to larger scale buildings as well, and many European structures are being built to these standards.

The continued increase in world-wide energy costs has led to higher performance expectations for the buildings we design. The Germans and the Japanese have established standards that mandate a low level of energy consumption per square meter of building area. These standards will soon be coming to North America. I would not be surprised to ultimately see performance criteria established for our buildings much as we already have mileage criteria for automobiles.

During the 1970s, I (and many others) designed low energy homes. These homes often had renewable energy collection systems and were either super insulated or double envelope houses. At the time, we did little to rectify air leakage or utilize much more than the crudest methods to measure building performance. Nevertheless, those buildings became the precedent structures that our design colleagues around the world are now emulating and improving on.

The principal behind the making of Passive House is simple: provide houses (or any building) with an exceptional thermal blanket. So exceptional, that all one might need to heat the house is a single candle or some form of minimally fueled heating device. The higher cost of fuel has spurred the European Communities to accelerate their quest for the more “perfect” building. Many of us in North America are again in quest of this perfection.

A Passive House is more than just an ultra thick blanket of insulation, however. The “blanket” must be designed to minimize air leakage, and as we all know, it can get stuffy under a blanket that doesn’t offer some modicum of ventilation. Enter an effective ventilation system that supplies fresh outdoor air. Ventilation is essential, but when we ventilate in our cold climate we dump lots of warm, stale air into the winter night. So, we ventilate with what is called an energy or heat recovery ventilator. In slightly more moderate climates (such as much of Germany), an ERV is about all that’s needed to heat a super-insulated and non-leaky home.

Here in northern Vermont we need a little extra heat, and this can be provided by an electric heating coil placed within the ductwork of the ERV. Or, if a little romantic bio-fuel is desired, one could install a pellet or wood stove, perhaps with a hot water coil on the back to provide supplemental hot water for showers and washing dishes. Increasing in popularity is a mini-split air-to-air heat pump. These devices extract heat from outside air and add it to your interior heating needs. The advantage to these little babies is that they can run in reverse in summer and help cool your house. This device runs on electricity as well. It should be stressed that the heat load, even in our climate, is minimal. For the electric heating coil or heat pump, a photovoltaic array on the roof would supply the electricity required for the coil/pump as well as supplying additional renewable power for your home’s lighting and electrical needs.

I believe the idea behind passive House is sound. Spend a little extra money on the building envelope and save money on the cost of a heating plant and distribution system. The Passive House has fewer moving mechanical parts and very high overall building performance. Save money on heating fuels (the cost is only going up), and dump less carbon into the air. All is good.

A couple of other points worthy of discussion: with a sound building envelope, fresh air supply and a modest heating source, we still need natural light to live and grow. While windows are vastly improved with regard to thermal effectiveness, they still fall far short of a well-insulated wall. So Passive House logically places windows on the south side with more modest amounts of glass on the east, west and north. A good window on the south side of our houses, even in the Vermont winter, is still a net heat gain, so this glazing contributes heat to the house’s needs.

Passive House is a great idea. The certification process looks complicated, but the design and calculation principals are sound. A good rule of thumb is keeping the shape of your home straightforward… even box-like. Think of our ancestors who populated much of the New England landscape. Their buildings were remarkably straightforward and often the more elegant for that simplicity. That simple beauty lies at the root of our building traditions and Passive House seems like an idea that New Englanders will embrace.