A Renewable Energy House
A Renewable Energy House, by Shawn Lawrence and Rebecca Otto
Breezy has many unseen, state-of-the-art features that make it extremely low-impact on our environment. This synopsis contains some brief highlights on many of the key energy saving elements.
Superinsulation. Most houses are insulated to R-11 in the walls and R-25 in the ceiling. Our 2×6 walls are insulated with high-performance R-21 fiberglass and sandwiched with two layers of 1/2″ aluminum-foil-faced foam sheathing, each sheet carrying R-5.5. On the main level, we glued 2″ thick R-10 foam to the block, then built stud walls inside that, filled with high-performance R-13 fiberglass. Overall, our walls are R-33. Our attic has a double layer of high-performance R-25 fiberglass, and 4-mil black poly vapor barrier. Overall, it’s rated at R-55. We laid 2″ thick R-10 foam down before we poured the main floor slab. At the rim joist, where the second floor sits on the first, we held the framing in 2″ from the outside and installed R-10 foam in this high-leak spot, then foil foam over that, and insulation stuffed inside. Overall, the extra cost to superinsulate was about $2,000, or about $.60 per square foot. Payback: 4 years.
Airtight construction techniques. The most common causes of modern home heating inefficiency are the many holes caused by installing wires and pipes in the walls and by poorly installed vapor barriers. In Breezy, all these holes have been sealed with caulk, and all seams in the vapor barrier have been sealed. There is a thick plastic film under the slab, wrapped up around the exterior walls, and across the ceiling, all sealed together without a break. You are standing inside an airtight plastic tent, which has been hidden by the sheetrock.
Air-to-air heat exchangers. With such airtight construction, it becomes important to protect our indoor air quality. We provide the interior with high-quality air with two Van-EE heat exchangers. They continuously change the air in the house for fresh air from outdoors, warming the cold outdoor air in the winter with the heat from the indoor air as it is exhausted, recapturing 40% of that heat. They also monitor the air quality and kick into high gear if they detect carbon monoxide, smoke, or other air pollutants. We have fresh air all winter long with minimal heat loss.
Passive solar design. All the southern glass picks up a ton of heat in the winter when the sun is low in the sky. The sunlight falls deep into the rooms and is absorbed downstairs by the tile-on-concrete floor and the fireplace, upstairs by the massive wood floor, and throughout by the massive 5/8″ thick sheetrock. All these things are inside our insulated envelope, so they act like big radiators, soaking up heat all day long and radiating it at night. In the summer, this doesn’t happen because the angle of the sun is higher in the sky and the eaves and deck on the south side project far enough to shade the windows from direct summer sun. In the summer, we use the stack effect to stay cool: the low south windows and high north skylights (in the library) cause a breeze to form in the house, sometimes blowing doors shut even on still days, as warm air is heated, rises and escapes, drawing in cooler air from below. We stay pretty cool all summer long, and most winter days we come home to 80 degrees, and the heat hasn’t been on all day.
Recycled wood floor. The second floor is eighty five years old. It is old growth Douglas fir from Washington State, which was the floor to the shell manufacturing plant at the arsenal in New Brighton. When the post and beam building was torn down, we bought a ton of this old 2×6 tongue & groove flooring. We like its old character and thought it was perfect for both the interior period style and the ethical motives of Breezy. Plus, the extra heft added needed thermal mass to absorb heat and reradiate it slowly at night. Unfortunately, we didn’t know it had been rained on and was swollen when we installed it, so it shrank and cupped after installation. We used the same stuff for our horse stalls and hayloft in the barn, which was framed with recycled joists from the same place.
Masonry wood heater. The big fireplace in the living room is actually adapted from a very sophisticated German design. We hand built it from parts cast in Vashon Island, WA, then put the stone around the outside. The fires burn very fast and very, very hot (over 2000 degrees F). The “glass” in the door is actually clear ceramic to withstand this heat. The smoke is routed through a labyrinth of chambers where it is reburned and a lot of heat drawn out of it into the mass of the masonry (the fireplace weighs about 6,000 pounds, or three tons). By the time the smoke leaves, it has cooled to about 300 degrees, the extra heat remaining in the house. The fireplace acts like a huge radiator, and stays about 100 degrees on the surface 24 hours a day. We burn only one fire a day. Also, on top of the fireplace we installed a hot water heat exchanger coil, which absorbs extra heat from the fireplace and puts it into the hot water heating.
Wirsbo in-floor heating system. Wirsbo is a Minnesota-based Swedish company that manufacturers a high-tech polyethylene tubing that is cast into the main floor slab. It is laid out in a serpentine pattern, and hot water from the boiler is pumped through it. This way when the heats goes on it warms the floor, which is a very pleasant experience. Unlike forced air systems, the heat doesn’t rise to the ceiling since the air is not being heated but stays evenly warm throughout and feels great underfoot! The second floor is heated by baseboard radiators. Often, the boiler does not have to fire because either the house is warm from a sunny day, or the water has been heated by the fireplace throw-off heat instead. This triple heat source—sun, fireplace and boiler—provides extreme flexibility for lifestyle variations and incredible winter comfort.
Earth bermed, airlocked design. Many people are confused when first entering our split-level house, because they don’t expect to go down to get to the main floor. This is because the entry is on the north, and the north is bermed. We designed the house as if it were a traditional style two-story country home built around 1918 or so, except that its sunk a bit into the hill. This reduces the northern profile substantially (the house looks remarkably smaller when viewed from the north versus the south—try it!), and thus, our exposure to cold north winter weather. Also, we put the garage on the north as well and minimized north-facing windows. You will also note that every door has an airlock-style entry: the front a small porch entry, the side, back and garage enter into the closable laundry/mud room, and the south sliding door enters into the sunroom. The only exceptions are the two other bedroom sliding doors, but you can’t have everything. This airlock system limits heat loss through doors in the winter.
Super-efficient appliances. The Asko washer and dryer are Swedish in design, and use about 1/6 the water and detergent, and yet get the clothes much cleaner using less energy. The first time you do a load, the manual says, don’t use any detergent. The residual detergent left in your clothes by your old washer will be more than enough to do the trick. This miracle is accomplished through the front load design, which is far more efficient. Laundromats have known this for years. The same story goes for the Bosch dishwasher. Turn it on – you can barely hear it. Its stainless steel liner and thick insulation make it quiet as well as efficient. By recirculating the water through a series of filters, it triple washes, then triple rinses, and uses 1/6 the water of most dishwashers, and actually less than if you wash and rinse by hand. The Amana fridge is also the most efficient mass-produced domestic model available today (1995). The freezer is on the bottom for a good reason—because heat rises, and cold sinks. Keeping it low makes it more efficient. When the fridge calls for cool air, a little is blown up from the freezer, using a fan. This eliminates the need for a second compressor and greatly increases efficiency. The Turbosoft water softener in the basement recharges based on water usage, not days of the week, and since our usage is so low, we save big time on that! All our toilets flush by only emptying half the tank, using only 1.5 gallons per flush. The tanks don’t sweat because the new cold water is tempered by the half a tank of warm water still left! Our shower heads are super-efficient also, using 2.25 gallons max per minute, compared with 4 in a normal shower. Check out the blaster in the master bath—it rivals anything you’ll find at 4 or even 6 gallons per minute. The boiler is a Utica and runs at about 80% efficiency. It has electronic ignition and an automatic vent damper that closes the vent when it’s not firing. All combined, we use about 1/4 the water and 1/2 the electricity of a typical house this size. This pays us back in lower electric costs, lower wear and tear on pipes, septic system and appliances, and a great feeling about doing our part to help slow the process that’s eating the world’s resources like a hog in slop.
Wind generator. Most of our electricity comes from the big Jacobs wind generator in the back yard. It generates a peak of about 15,000 watts (15 kilowatts) in a 25mph or faster wind. This is enough power to light 250 60-watt light bulbs or about 10 houses worth. The wind turns the 24′ diameter airfoils of the propeller, which turn a big alternator, which generates three-phase wild AC current. Wild means the voltage goes up and down with the wind speed—it’s not tamed to a constant 120 volts like normal house-pet type electricity. This wild power comes down the tower and to the house through some cables we buried underground, where it enters the garage and hits a big mess of electronics called an inverter (the big metal cabinet in the garage) that turns it into normal line-quality electricity. If we are generating more than we happen to be using at the moment, it gets sent back out our lines to Connexus Electric Cooperative, which buys it from us at the retail rate. If we are using more than we are generating at the moment, we draw part from the generator, part from Connexus. It’s a sweet system that supplies about 80% of our power. Connexus makes all their power by burning coal, which of course pollutes the air and puts mercury into our lakes, so we feel pretty good about this rig. All told, we figure we are generating enough power to prevent the burning of about 28,000 pounds—about 14 tons—of coal every year. Plus it’s a big charge, so to speak, watching it turn. We always know what’s up with the weather, which way the wind is blowing and how hard. It’s a more intimate connection with the sky. We like it.
Super-efficient lighting. Much of our lighting is either compact fluorescent or halogen or converted DC bulbs. When it’s not, we have special dimmers or automatic timed shut-off switches to conserve electricity, which is far more efficient than trying to generate it! Even the barn and riding arena are high-efficiency, with the lighting there being high-pressure sodium. Six seventy-watt fixtures light the 40 x 80 tool shed area up bright as day, using less than a seventh of what normal lights would require. We save about $400 a year on this, so the payback is less than a year, and the benefit to the environment is, again, substantial on a per capita basis.
Off-peak hot water. We have a separately metered hot water heater, which is turned on via radio control by Connexus Electric 6 hours at night and 2 during the day. We pay only 2.9 cents per kilowatt hour (compared with 7 cents for normal electricity). This gives Connexus some place to dump their extra power at night when demand is low, since they can’t really scale back production that fast. This is power that would otherwise be wasted by dumping it into a heat sink in the ground. The cost equals gas, and we NEVER run out, because the water is heated hotter than we need, and then mixed with cold through a mixing valve set for our volume of use.
Clean wiring techniques. Electricity doesn’t just travel in wires; it also travels in a field around the wires. Wires that are spread apart instead of bunched together increase the size and strength of this field. The field can easily be measured with a gaussmeter. Certain studies have indicated that these fields may be implicated in causing certain forms of cancer and other nasties by disrupting DNA replication. In Breezy, we figured it was easy to take some precautions, so we did. Our wires are bunched wherever possible to keep fields to a minimum. They are also routed away from sleeping areas and places where we hang out a lot. By careful layout, we spent maybe an extra $50 for wire and an extra 3 or 4 hours of time, but the house is much more electrically quiet than a normal house. Cheap insurance.
Sunroom. The sunroom is a nice place to hang in the winter, but it also is a heat gatherer. It is thermally isolated from the main house, so when we close it off in the winter it gets up to about 100 or 110 degrees on a really sunny day. At night, we open the doors, especially on the second floor into our bedroom, and let this nice warm air soak into the house all night long. This also acts as a huge buffer across much of the south side from the colder outdoor temperatures, greatly reducing heat loss. We do still have a Wirsbo zone out there, so it could be heated like a normal room. Last year we just set it at about 45 and let the sunroom do its thing. It was always comfortable.
Maximizing technology. Humans have never wanted to go backwards. Less comfort, security, pleasure, utility, convenience and strength are not options most people will consistently choose in their lives, even if it is for the betterment of their own bodies or the environment as a whole. We’re wired to eat fat and lay around. This is why selling people on consuming less, conserving more, paying more and getting less has always been a failing political position, even if it’s the smartest long-term approach and the least costly one. The answer to environmental problems, then, isn’t to get people to drive less. It’s to improve our technology with more efficient cars or alternative, lower polluting cars. Or heating systems. Or packaging. Or water use. There are billions of people in the second and third world that are just now beginning to adopt the inefficient technologies that have caused so much of our environmental damage. They won’t give them up because, after having them ourselves for decades, we now tell them it will be better for everybody if they forgo these conveniences. And neither will we. In the long run, the only solution to environmental degradation is improvement of efficiency and quality—and lowering of waste byproducts, which amounts to the same thing. The best thing anyone can do to help the environment is to hasten this development along by becoming a research scientist, or adopting new technologies in our lives, or by spreading the word and challenging people to not just think about these issues but act on them, or by encouraging legislation that supports science education, science and technology grants and legislation that encourages industry to continue to push the technology envelope, especially in regards to increased efficiency. Science and technological innovation—smarts—are our best hope.
WHY? We have asked ourselves that many times during this building process but always about the process, never about the efficiency decisions we’ve made. Since we built the house ourselves, we could indulge our design ideas, which we gleaned from years of research into renewable energy. It costs more to put quality in up front, but things last longer and work better, with much less carrying cost and carrying waste over time. Buying top quality is best for the environment. For us, it comes down to this:
Do something about what we believe in. If our environment goes to hell, not a lot else will matter any more. We want a quality world to be here for our son Jake when he is our age, and for his kids and grandkids and great-grandkids. Its up to us to tip the scales that can help make or break that picture. We wanted to show that it could be done in style, with smarts, not sacrifice. Breezy is not just a house; it’s an attitude.
Note from Mike: Since this original write-up, the Ottos have added a geothermal heating installation. Some may think that what they are building is overkill, but I say that it is a case of leadership. If new houses are each built with only one of these energy-saving features, we could go a long ways towards reducing the need for coal, natural gas and oil.
This entry was posted on Tuesday, March 17th, 2009 at 5:49 am and is filed under Features, Science, The Candidates. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.