5 Green Building Ideas You Can Use (from the Net-Zero Energy House of the Future!)
Have you ever heard the term “Net-Zero Energy House”? If you have and you know what it means then I probably already have your interest. But if you don’t know that term, let me explain it in the way that matters most… no electric bill. Ever.
Since I pay a pretty hefty monthly bill for electricity here in Florida, the idea of a house that supports itself has had my interest for awhile. I gotta build me one of these. If I really do it right, I can actually get a check from the power company for excess electricity I sell back to the grid! How cool would that be?
This ongoing interest in ultra-green structures led me to Philadelphia last week where I attended the Greenbuild Expo and visited an awesome project house called the GridStar Center which is a collaborative effort involving the US Department of Energy, Penn State University, and a number of innovative building product manufacturers including the folks at CertainTeed, who invited me over to visit the project.
The collective goal was to design a house that included the full gamut of modern technology and had about the same relationship with electricity as a cactus does with water. (It creates and stores more than it actually uses!)
A full run-down on every component in the house would probably be of equal length to the entirety of this blog, so I’ll just point out a few of the features that held the most interest to me and that I think will have the most impact overall in the future.
Integrated Solar Panel Roofing System
About fifteen years ago (I was but a wee young contractor then), I asked a good friend about the future of solar energy. A renewable energy expert and inventor who held more patents than you could count on your fingers and toes, I figured if anyone could see the future it was him.
So I asked him, “What do you think about solar? Is it worth getting involved in?” “Not really”, he replied, “It’s far too costly to make the photovoltaic panels. They cost more than the value of what they can produce.” So I stopped paying attention to solar for awhile.
Oops. He was wrong. It happens.
Solar panels are getting less expensive by the day and have clearly reached a point where good quality PV panels are justifiable both economically and environmentally.
However, one major drawback has remained… solar panels are usually dog ugly.
Massive traditional panels have to be arranged in arrays either on stands out in your yard (unless you’re lucky enough to have a “North 40”) or on your roof. The on-roof arrangement is constantly running afoul of HOA bylaws, building codes, and the general sensibilities of those of us who like houses to look pretty.
CertainTeed, who manufactures roofing materials and fiberglass insulation among many other building products, might have solved this major problem of aesthetics by developing a solar panel system that integrates directly into the shingle roofing system. While not yet the futuristic idea of “solar shingles”, this is getting pretty close.
The Apollo PV System from CertainTeed shown in the photos here, provides the GridStar House with 4kw of electricity, about what you would get from the typical 4000 watt generator. For a house with very high-efficiency systems and a reliable way to store energy for times of no sunlight and/or peak usage, 4000 watts could be enough to get the job done.
The best thing about this PV system is that it looks great, especially with black shingles.
R-68 Attic Insulation System
No matter where you live, attic insulation is one of the most important factors in home energy efficiency. Where I live in Florida, it’s arguably the single most important factor. In cold climates, heat loss through the attic and various holes in the building envelope are the main culprit. In hot sunny climates, the radiant heat coming from the sun baking on your roof is the biggest deal.
Both of these are helped tremendously by a well insulated attic. Luckily for you and me, this is also one of the easiest and least expensive ways to beef up the efficiency of your home.
The GridStar house uses a nifty truss design feature called a “raised heel” to gain more space along the edges of the attic. This, along with 2×10 bottom chords (ceiling joists on a truss), let the GridStar builders install two layers of CertainTeed Batt insulation, R-38 between the trusses and another layer of R-30 run perpendicular on top, for an R-value of 68! (more than double the current standard in most warm climates).
This kind of insulation thickness greatly reduces the load on the HVAC equipment, thus lowering energy needs of the house.
R-30+ Wall Insulation System
Essentially the same concept as the R-60 attic, the thicker wall structure allowed for more insulation in the walls, which in rebellion to the current trend in ultra-efficient homes, is not sprayed foam.
The GridStar home uses CertainTeed’s Optima blown fiberglass insulation system which is blown behind a retaining fabric stapled to the framing and results in highly efficient insulation with an R-value on this 2×8 wall structure of up to a whopping R-40! (total yield including framing) To put that in persepctive, it’s more than three times the old-fashioned R-11 batts in a 2×4 wall and even beats the performance of seemingly impervious construction methods such as Insulated Concrete Forms (ICFs).
Assuming you don’t leave the windows and doors open when you go to bed, that is. For wall insulation to have the greatest effect, the overall lack of “air leaks” is very important.
A/C or D/C Mini-Split Air Conditioning
One of the challenges of creating your own electricity is that you can’t always create it when you actually need it. The sun doesn’t shine every day and, unless you live in the polar regions, it never shines at night, making solar energy a “sometimes available” proposition. Wind energy is equally sporadic.
So for sustainable, small scale, power generation to work, you need a way to store the energy you do generate. This is usually accomplished through the use of batteries.
Without getting too technical, I’ll just clarify that most (probably all) solar panels produce DC (Direct Current) electricity, which is the same as what batteries store and provide. The power grid, on the other hand, uses AC (Alternating Current) electricity which is much more efficient for long distance transmission.
Since our world pretty much relies on the power grid, most of our appliances are powered by AC electricity, including systems critical to building comfort and living such as Air Conditioners, Refrigerators, and Flat Screen TVs.
Therefore, energy that is created by solar roofing during the middle of a hot day but not used is stored in large rechargeable batteries (think golf cart battery on steroids). In order to use that energy later to power the fridge, it must be converted to AC power using a component called, as you might expect, a converter. This process involves some loss of energy. That’s why appliances that can run on both AC and DC are helpful and more efficient.
I say all that to say this: The GridStar house sports an Air Conditioner that can run on batteries! While maybe not the most thrilling thing you’ve ever heard, this is kind of a big deal and I, personally, am pretty stoked about it.
Electric Vehicle Charging Station
While I still happen to drive a gas powered (awesome Jeep) vehicle, I think we all see the writing on the wall regarding the future of electric vehicles. They will soon be the norm rather than the exception which is why the forward thinking GridStar project includes a self-contained electric vehicle charging station.
High-tech it may sound, but in reality we’re talking about a carport with solar panels on the roof wired to a plug for the car. (It’s slightly more complex than that, of course.) These particular solar panels were provided by another partner and, as you can see in the photo below, are much more obtrusive than the integrated solar roofing.
I just thought it was a pretty cool thing to think that one of these days I could buy an electric car and never pay another cent to power it because every day while I’m out driving it, my carport back on the farm is collecting solar energy and storing it. Then when I get home I plug the car in and essentially “download” all that energy captured during the day, never spending a penny for gas or for electricity from the power grid. That’s a pretty cool thought.
If you want to learn more about the high-tech GridStar Center, including learning about the many systems and features I didn’t mention, check out a few of these links:
I spent quite a bit of time at the GridStar Center and learned much more than I’m sharing in this (not so short) post, so if you have any questions about this house, please feel free to ask in the comments.