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The Sustainable House™

Illuminations and explanations of the major technologies in the house, from new-fangled to old-fashioned, using text, pictures, and illustrations. The thumbnail pictures in each article expand when you move your mouse over them.


One of the easiest ways to improve a home’s energy efficiency is to use EnergyStar-rated appliances. EnergyStar is a system of guidelines developed by the EPA and the Department of Energy to demonstrate the energy efficiency of appliances and other products. Using an EnergyStar-rated model instead of an unrated model requires consumption of less energy and saves money over the long run. The Sustainable House is outfitted with EnergyStar products wherever possible, including the refrigerator, clothes washer and dishwasher, three of the home’s most wasteful appliances. For appliances with no EnergyStar guidelines, such as the stove/oven, Live Green, Live Smart is choosing the most efficient models available for the application.

Compact fluorescent light bulbs

The incandescent light bulb is one of the world’s most pervasive and inefficient appliances. Only 10 percent of the electricity burned per bulb is given off as light, the rest is wasted as heat. Fluorescents, although more costly at the check-out counter, will more than pay for this cost over their lifespan. They throw off less heat and more light per watt, making fluorescents remarkably efficient. Switching just one bulb in your house will save about 300 pounds of coal over the life of the bulb. New fluorescents suffer from the reputation of their prototypes, which cast a dull light; new fluorescent bulbs look more like and even have the same warm feeling as natural light, making them a big bargain.


Natural quartz countertops from Cambria are installed in The House. The quartz is locally quarried and twice as strong as granite. Cambria recycles 98% of the water used in the polishing process and is Greenguard certified under the standard for Low Emitting Products. The final surface, from Easy Clean Home and DFI, is stain resistant and requires no sealing or polishing. The product is certified by the National Sanitation Foundation: the non-porous surface ensures that harmful bacteria or other toxins cannot be absorbed into the countertops, making it a safe product.

Dual Flush Toilet

Each bathroom in The House is equipped with the Aquia™ Dual Flush Toilet made by Toto. These toilets conserve water with a 1.6GPF / 0.9 GPF system with a push button style flush option that allows the user to control the “amount” of flushing, and has a fully glazed trapway that is easy to clean, reducing bacterial buildup. The dual flush toilet is widely used in northern Europe and Australia in response to water shortages.

Fly Ash Cement

Our cement mixture contains 40% fly ash, which is a mineral residue from the combustion of coal in electricity generating plants. This ash would ordinarily be discarded into a landfill, so its reuse saves landfill space, reduces sand and gravel mining, and increases the strength of the cement – while reducing its cost.

Freewatt by Honda and ClimateEnergy

In a combustion reaction – like the burning of natural gas – both energy and heat are produced. A typical generator uses the energy and wastes the heat; a typical furnace uses the heat, but not the energy. The ClimateEnergy/Honda Freewatt combined heat and power (CHP) system takes full advantage of the combustion reaction and uses both the energy and the heat productively. Natural gas flows into the CHP unit, which produces 1.2kW of electricity and 12,000 BTUs of heat simultaneously. The electricity is used to power lights, low-voltage systems, appliances, etc. The heat is put into a high-efficiency, low- and constant-flow furnace. Unspent gas also goes into a catalytic converter, which produces more heat and also reduces emissions to zero.

FSC Certified Wood

With very few exceptions, the wood used in Live Green, Live Smart’s The Sustainable House™ is either recycled from teardown projects, or is FSC certified.

The FSC (Forest Stewardship Council) was established to enforce responsible management of forests cultivated for industrial purposes such as lumber or paper. The FSC standards require that trees are not cut faster than replacements grow, and that the ratio of new trees to cut trees is balanced in these forests.

A feature of FSC’s certification is that each piece of lumber can be traced back to its source. Live Green, Live Smart™ has used three different types of wood from FSC certified forests in The House:

  • Western red cedar from a forest near St. Maries, Idaho
  • Hemlock-fir dimensional lumber from the Warm Springs Indian reservation in northern Oregon
  • Plywood from a forest owned by Roseburg Forest Products, Inc., located near Dillard, Oregon


If you dig 130 feet into the Earth, the soil is a constant temperature year-round – about 55-60°F. A geothermal system takes advantage of this stable temperature to heat or cool a home sustainably with renewable energy. Underneath the House’s front walkway are four 130’ deep closed-loop wells, which circulate a non-toxic glycol fluid. Inside the house is a WaterFurnace that exchanges heat between the earth and the house.

When the house air is warm and the earth is cold, this system acts as an air conditioner. The fluid – which is warmed by compressed refrigerant and heat from the house ­– loops through the earth, becomes cold, and returns to the house. In this way the earth acts as a heat sink – heat from the house is deposited in the earth. A traditional air conditioner actually blows cold air through the house, while this system simply takes the heat out of the hot air.

When the house air is cold, the cycle is reversed. The solution running through the earth becomes hot, which heats the refrigerant in the WaterFurnace and turns it into a gas. This heated gas is compressed, making it even hotter, at which point the heat is transferred to the cold air of the house, making it warm. The glycol solution, now cooled, goes back into the earth and continues the cycle.

Greywater system

When you think about it, it doesn’t make much sense to use fresh, clean water to flush our toilets. It makes more sense to use recycled water, or “greywater.” In the House, the Brac greywater (it’s not actually grey) recycling system takes water already used in showers and sinks, filters it, and reuses it in the toilets. Greywater is water that isn’t potable without further treatment, but that is still safe for human contact.


One of the most important features relative to a home’s energy efficiency is insulation. Because the House was originally built in 1948, the insulation used was woefully out-of-date: six-inch-thick stacks of fiberglass batt and paper. An energy audit proved the obvious: the House’s insulation was useless; heating the house was throwing money directly into the furnace.

The House’s new insulation from Dow is both energy-efficient and a space-saver. The outside of the house is covered with 1” thick Dow “blue board” Styrofoam, and the foundation is wrapped in 2” Styrofoam. Inside the house, closed-cell foam insulation is sprayed in between the studs. Unlike fiberglass, this spray foam expands to create an air-tight and water-resistant seal (which also reduces concern about mold and mildew), and it won’t contract over the lifetime of the House.

This insulation combination creates a relatively thin barrier—about 3-4”—with a surprisingly high R-value of around 29. The insulation is also non-toxic and won’t gas-off into the home.

Passive Solar

Passive solar design is not new - ancient civilizations used passive solar.  Because The Sustainable House is not a south facing building (best for passive heat control in a cold climate) we incorporated as many techniques as we could to manage the summer and fall sun.  We utilized techniques that helped us manage: direct gain, indirect gain and isolated gain.  To take advantage of the sun for energy and heat gain we added a solar hot water heating system, increased the exterior thermal wall mass using stone and stucco, put a cement floor at the exterior entrance, and used dark shingles (in hot climates these should be as light as possible).  Our flooring in much of the first floor is hardwood or ceramic to collect and release the heat; the walls are a 3/4” drywall to hold the heat.  We have a high R-value closed-cell spray foam in all our exterior walls and lid. In the crawl space and attic there is an additional layer of recycled fiber insulation to maximize heat or cooling retention. Our windows and doors are the maximum U- and R-value. Low-E film on windows keeps the home comfortable and aids in control of the gain or loss coefficient.  High efficiency shades on most windows keep rooms further insulated. 

For the cooling months, our roof has an overhang that reduces the impact of the sun by shading the windows.  Blinds are used to screen the sun.  Light colored exterior walls reduce the collection of the sun’s heat.  Proper venting and insulation in the attic spaces and walls keep the house cool.  Windows are arranged to allow fresh airflow throughout the house and in the evening flush heat by natural ventilation.  The house is properly landscaped to take advantage of shading from trees.  Large windows and sky-lighting tubes space placed correctly around the house give us plenty of natural light from early morning to dusk reducing the heat gain from artificial lighting.

Photovoltaic panels

Solar energy is the planet’s first, most abundant, and most powerful energy source. One of the easiest ways to use solar energy is on an individual, per-house basis using photovoltaic (PV) panels. When sunlight hits a PV panel, it agitates electrons and knocks them loose from their atoms, creating electricity. This electricity is focused into special circuits, forming an electrical current. The current is run through an inverter, at which point it can be used in a number of ways: on-the-fly to power the home, going straight into outlets; stored in batteries for later use (at night or on cloudy days); or sold back to the utility at times when the PV generates more electricity than the house needs.

Radiant in-floor heating

People are most comfortable when their feet are warm. Warm air rises, so if forced air from a furnace heats a person’s whole body but leaves the floor and feel cold, the normal tendency is to turn up the furnace. Radiant in-floor heating helps save on energy costs by keeping feet warm, thus keeping thermostats turned down. STEP Warmfloor is a flexible, thin plastic mat that heats when electricity is passed through it. Because STEP Warmfloor uses low-voltage electricity (as opposed to traditional systems that use heated water), it is cheap to use, self-regulating, easy to maintain, and completely safe.

In the House, STEP Warmfloor will be used in the mudroom and the bathrooms under ceramic flooring, where our feet are most susceptible to cold and wetness. In-floor heating has the added value of inhibiting mold and mildew growth because it keeps the floor dry.

Richlite Table Tops and Work Surfaces

All the table tops and work surfaces, such as in the lower floor, are made from Richlite, a product made of compressed paper, pulp, and resin. Richlite has a non-porous, scratch, stain and heat resistant surface. This is the first-ever application of Richlite FSC, which combines 30% of the rapidly renewable Eucalyptus (hardwood) fibers from Brazil and 70% Pine (softwood) from Sweden. 

Solar Hot Water System

Solar heating systems employ three basic elements: thermal collectors, a circulation loop, and a water tank. A nontoxic heat transfer liquid is pumped through the circulation loop first to the roof, where it is run through the thermal collectors. These absorb and focus the sun’s heat on the transfer liquid. The heated liquid continues through the loop to a water heater. Here the fluid is dispersed into a fluid jacket that surrounds a tank of cold water. The water is heated as used throughout the house. The cold fluid is sent back up to the roof, and the cycle continues.

This system is used as a replacement for traditional a water heater. It is sufficient to provide the hot water needed on most days. On days when more hot water is needed, a small backup system kicks in and makes up the difference.


Solatubes provide natural sunlight all day long, reducing electrical needs and conserving energy during peak hours. A Solatube differs from conventional skylights: rather than a window opening directly onto the roof, a Solatube is made of a half-dome shaped sunlight collector that efficiently gathers sunlight all day long, no matter where the sun is in the sky – this portion of the fixture shows at the roofline; captured sunlight passes down a highly reflective tube into the home; where it is diffused into rooms through a “lens” that looks like a traditional light fixture. A Solatube can even bring natural light underground – the House features one in the basement bathroom.

Wind Generated Electricity from the Grid

Despite all the innovation in use to make the Sustainable House energy efficient, the home is not fully self-sustaining. Electricity from the grid will still be used.  The local electrical utility, Xcel Energy, has responded to consumer and state demand that a significant portion of its energy portfolio be renewable. Xcel offers customers an option to buy some or all of their energy from a renewable source – specifically, wind power “farmed” in the region. Any electricity the House uses from the grid will be 100% wind generated – not a kilowatt of coal energy will be used.


The average window is one of the weakest points in a house system. With an R-value of 1-0, standard windows do little to keep heat in or out. According to the Lawrence Berkeley National Laboratory, the energy lost through inefficient residential windows accounts for two percent of total U.S. energy consumption. Two percent of the country’s produced energy, literally out the window. The casement windows in the Sustainable House, from Marvin, are triple-glazed, utilize a “low-E” coating, and are filled with argon gas (which is inert). All this means that these windows have an R-value around 8 – an eightfold increase in insulation over standard windows. These windows are especially suited for very cold climates – perfect for the Minnesota winters.

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