When people learn that I design high performance homes I often get the question, “does that mean solar panels and stuff like that?” “Well,” I say, “maybe….eventually.”
What I also tell them is that I’m more concerned with getting the house to perform, on it’s own, very efficiently, be very comfortable, and last a very long time. Then, and only then, do I “consider” adding solar panels or some other alternative energy.
This approach will not only reduce the amount of solar arrays that the house needs, but in the event that the sun is temporarily unavailable for the panels to collect it’s energy, the homeowners will “pay for” a lot less energy.
To achieve this, a home must be designed and built as if it is a system of parts where every part is critical to the performance of the whole. This includes everything from the finish details to the mechanical systems. It should also be designed and built for it’s climate (e.g. a home built for Georgia winters will NOT be comfortable in North Dakota at Christmas time). Finally, a home must protect the homeowners from unwanted moisture, air and temperatures. Oh, and it really has to be appealing in character…
Case in point
The Proud Green Home we are designing in the Serenbe Community near Atlanta is a great example of this “performance-first” approach. Our goal is to achieve “net-zero”, and the only way to do that is to have some onsite power generating source. In our case, we’ve chosen solar panels.
Before we determine just how much solar power we need, though, we are concentrating on the building envelope (walls, floors, ceiling, windows, doors, etc.) to ensure comfort through proper insulation and keeping unwanted air and water where it belongs. This will also keep the amount of unwanted heat loss and and gain to a minimum which will reduce the need for mechanical heating and cooling.
The next areas we will focus on are: 1. Specifying and installing energy efficient heating and cooling (HVAC) Systems, appliances and light fixtures. 2. Keep the amount of windows to a minimum and 3. Provide adequate shading for the windows we do have.
In the end, we will be reducing the need for electricity, which will decrease the amount of solar power needed.
How Low Can We Go?
The goal is not to design a roof big enough to handle a large array of solar panels, but instead it’s to design the house to only need a tiny array.
Right now, as part of the overall design process, we’re running a series of energy modeling exercises to determine the best building envelope that will achieve the results we’re looking for. The results will have an effect on the amount of solar, the building envelope assembly and the HVAC System. This is why it’s called “integrated design” (a topic for another day)
Stay tuned for the results and more info on how we will achieve our goals of comfort, durability and efficiency…oh, and net-zero, too!
– written by Chris Laumer-Giddens, Architect, HVAC Designer, Building Science Professional, LEED AP