The Campbells | Net-Positive Home
Jared and Mindy Campbell are scalers of rocky cliffs, runners of hundred-mile races, and admirable savers of the world. That is, they’re looking to try. First order of business: build a stylish, modern, passive-solar, net-positive home. Check. These folks aren’t architects…they’re just aware.
The amazing, efficient home we speak of is in Sugarhouse. ‘Net-positive’ is a term assigned to a structure that actually generates as much or more energy than it consumes. It’s not something that costs boatloads of money to create; it just requires a bit of research and the willingness to commit to the necessary design. The Campbell’s home is beautiful — the visual aesthetic they’ve created is as impressive as its sustainability — and they managed to complete it for less than it would likely cost to buy a typical home in the same ‘hood. The floor plan is open and spacious, the lines are clean and modern [mmm…concrete floors], and no detail’s been missed. The living room is home to a steel ‘solar wall’, on which bands of steel correlate with the sunlit spots during various months. Seriously…they power two electric vehicles from their home. Seriously.
The Campbells are kind of a big deal. They’ve set a new and perfectly-attainable standard for the rest of us in terms of reducing our carbon footprint [something that should be at the front every local’s mind…cough, cough]. Watch for more from these two — they’ll speak on how to recreate what they’ve done at some public seminars this April. Now read on for the gloriously-geeky details…
Having built this house, is there a message you’d like to pass on to others? The main message I’d like to get out is that energy independence is well within the reach of the average citizen. With a small amount of thought, planning, and creativity, one can harvest all the energy they need for their home and commuting needs. And best of all, the simplest path to this independence involves taking advantage of the free and inexhaustible solar energy we are blessed with living in Salt Lake City.
What was the inspiration for this project? The inspiration came from many sources, but the initial thought process started with simple geometry understood by astronomers in Ireland over 5,000 years ago, solar communities built in 5th-century Greece, and the Anasazi cliff-dwelling Indians of Mesa Verde. This, coupled with modern building materials and now-incredibly-affordable solar-electric panels can render brilliant simplicity and over 100% of energy needs being met.
Without making your fingers too tired, touch on some of the key factors in the efficiency of your home:
1. Orientation — The long axis of the house runs east-west, perfect for SLC where our grid system is setup around true north.
2. Geometry — The simple roof lines, eave design, and window placement let in solar heat during heating months (late October through mid April) and block it out the rest of the year. Simple roof geometry keeps building costs low and provides for far more solar panels to be easily installed.
3. Windows — Window type and performance characteristics are key, and have to be carefully selected. This is in stark contrast to a typical window “package”, which often involves a remarkably cheap product with no differentiation in specs based on where the window is being installed. Our south-facing windows are very different than east- and west-facing ones. All south-facing windows have a high SHGC (Solar Heat Gain Coefficient), allowing a great deal of warmth to enter the house from the sun while still being a highly-insulated (R-value) window (7.1). The east- and west-facing windows are effectively quadruple pane for an extremely high R value (9.1), while also blocking out solar radiation. There are no north-facing windows on the north side of the upper floor. Very few window manufacturers understand why someone might want a high SHGC window, and consequently, there are few manufacturers who make them. Window companies in western Europe and Canada understand this, so often folks have to custom-order such windows from overseas. There is at least one U.S.-based company that “gets it”.
4. Thermal Mass — The surfaces that the sun hits are super important. The entire upstairs has concrete floors to store heat and stabilize temperatures, and we built a unique thermal storage wall with 400 lbs of a specially “tuned” Phase Change Material (PCM) that also stores heat and stabilizes temperatures. Utilizing the “latent heat of fusion” nature of the PCM, the almost-daily freezing and melting (which occurs at 73° F) of the material results in an “effective” thermal mass equivalent to that of a 12″-thick concrete wall in our main room. The steel facing on this wall is where art met science. We mapped out solar arcs and created bands of rust to follow the light paths cast onto the wall by the sun through a specific point in our upper clerestory windows.
5. Insulation — The thermal “envelope” of the house is extremely important. We chose Icynene for a high R-value wall, but also for for the resulting air-tight seal it provides. Ventilation is accomplished with a Heat Recovery Ventilator (HRV) to efficiently ventilate while not throwing too much heat away.
6. Photovoltaic — Our 7.9kW PV array harvests energy for all our needs: home heat, hot water, lighting, appliances, and an electric car and motorcycle.
Tell us about the “earth tube” creation. The “earth tube” is a bit of a science experiment wherein we take the incoming ventilation air down ~10′ underground where it traverses 100′ before it enters the house. That far down, the ground temperature is extremely stable over a calendar year, somewhere in the low to mid 50s (F). We are hoping that this will provided some additional cooling in the summer and pre-heating of intake air in the winter. With a well-insulated house, a typical energy-intensive air-conditioning system is not necessarily needed.
Give us an idea of the expense of becoming net-positive. Is it realistic for the rest of us to achieve? Becoming net-positive is very realistic, especially with new construction. Our project cost very little more than a “typical” house its size. It’s a matter of priorities and opening your mind to a slightly different house design. We put more money into the thermal envelope and windows than a normal house in our neighborhood, but it was essential given what we were trying to accomplish. We saved money in other areas. Contrary to what most folks think, solar electricity is incredibly cheap now. It is truly a no-brainer, in our opinion, if you have a somewhat-south-facing roof, especially with the current incentives (power company, federal tax credit, state tax credit). Yes, there is a substantial up-front cost, but after the credits/rebates, and provided folks are willing to do some work themselves, a PV system can pay for itself in as little as 2 years. The solar system on our house (we have two, one on the house, one on the detached garage) cost us less than $2,000 out-of-pocket in the end. With existing houses, it is also possible to become net-positive with a handful of energy-efficiency upgrades and a geothermal heat-pump.
What are some ‘green’ financial incentives that you took advantage of when building your home that some of us may not know about? Rocky Mountain Power (RMP) has extended their solar incentive program through 2017 (HUGE thanks to Utah Clean Energy for laying the groundwork for this); this will cover up to $5,000 of a PV system. The interest from local citizens is extremely high and it is a lottery-based system, so there’s no guarantees on getting selected for it. There is also an un-capped 30% tax credit from the federal government and a 20% tax credit from the state up to $2,000.
What’s the coolest thing about your house? I love our “solar wall”. It was a fun project of form, function, art and science. It serves a distinct function with heating/cooling the house, it has visually and emotionally connected us with the seasonal variations in the sun’s position through it’s calendar/time-based design, and it’s also quite artistic. It’s an immediate eye-catcher the minute the front-door is opened.
You’ve already accomplished an amazing environmental feat [or many of them] by building and living in a net positive home [and driving electric vehicles]. What can we expect from you next? I’m working with Utah Clean Energy to share the basics of what we’ve done with the citizens of Salt Lake City. We face unique challenges living in the bottom of what was once Lake Bonneville, most notably our air quality during winter months with temperature inversions. I want others to see that they can do their part, and in the process, literally save thousands of dollars a year. It’s a win-win, in my opinion. I hope to someday be providing consulting services for solar-based architecture and design/engineering services for homes and commercial buildings. Look for several free and open-to-the-public seminars starting in April, 2013, they should be listed on Utah Clean Energy’s website.