At the 2016 TXSES Annual Meeting earlier this year, we were reminded that today’s emphasis on solar PV may make us forget that the first approach to addressing our hot and humid Central Texas climate involves thoughtful passive solar design. We invited Peter Pfeiffer to expand on this important component of our built environment.
By Peter L. Pfeiffer, FAIA
As costs for solar photovoltaic systems continue their downward trajectory, energy from the sun becomes an increasingly compelling choice for homes and businesses. I served on the board of the Texas Solar Energy Society during its very early years and have been a member for three decades. As such, I see the current resurgence and am glad for it.
However, study after study shows the most cost effective energy strategy is simply using less. Although most conservation measures are not free, many are very inexpensive compared to the alternatives. These techniques often involve dealing with solar energy in a passive fashion, without resorting to mechanical or electrical devices.
Last time I checked, nobody was giving away prizes for the highest energy use in my neighborhood. But we are all eligible for monthly prizes for saving energy — the reward of a lower electric bill. These savings can quickly recoup your initial conservation investment and preserve your cash for more important things in life.
Less Is More
There are many ways to save on utility bills in your home or business without committing to solar, and without exposing yourself to any solar maintenance costs. What’s more, many strategies will even make the building more comfortable.
In what we call ”high performance” architecture, home and business owners can address energy-saving initiatives before investing in solar or other renewable energy production strategies.
These include making sure homes or buildings are not drafty or leaking air and humidity, and that duct systems are airtight. Leaky air-conditioning ducts are common and have a very negative effect on health and comfort, while wasting energy dollars.
Other factors to address upfront include excess solar radiation penetrating the windows and the roof, exterior colors that absorb heat, and excess electricity consumption associated with swimming pool equipment (if applicable). Planning the best use of electric lighting, interior colors, and water heating up front reduces electric bills over the life of the building, as does repairing poorly maintained or outdated air-conditioning and heating equipment.
In our climate, dealing with the infiltration of air and humidity, as well as shading windows and incorporating some sort of radiant barrier into the roof, offers a good payback in both cash and creature comforts.
Should Solar Come Next?
For most Texas properties, solar systems justify the initial investment cost, much more so than twenty, ten, or even five years ago.
Be careful to consider all the costs of installing and maintaining a solar system, not just the first cost of installation. Warranty periods are increasing, but be aware that a solar system is composed of several parts, each with their own warranty period. Still, all costs considered, including equipment, maintenance, and replacement costs, as well as the various financial and tax incentives, the payback period can be as low as ten years — sometimes even sooner.
These days, consumers have choices when financing their solar systems. Various programs can reduce or eliminate the upfront cost and maintenance, but these alternatives have trade-offs. Evaluate which financial arrangement works best for you.
Who Should Install Solar?
Almost anyone. I have them on my home, and have for over a decade; but then again, I suppose I could be considered one of those “building science” geeks.
Our company designed a home that was featured in the recent TXSES Cool House Tour in Austin that was completely gutted and remodeled. The energy conservation strategies incorporated into the renovation plans and specifications save the homeowners about $200 per month and have a payback time of two to three years.
The 9+ kW solar system installed on the roof saves another $100 or so each month, and has a payback of between 10 and 13 years. With the various strategies employed — energy conservation, passive solar design, and “active” solar panels on the roof — this home has an annual kilowatt consumption cost of less than $300 per year.
This remodel is a great example of how a 1970s “ranch” can become something much more comfortable, with better natural lighting and cross ventilation. It is easier to keep clean and free of dust, more architecturally dynamic, and far less costly to own compared to most homes in Austin.
Peter L. Pfeiffer, FAIA, is a founding principal of Barley|Pfeiffer Architecture and a nationally recognized proponent of passive solar design. In 2004 he was named a Fellow of the AIA for his life-long commitment to “mainstreaming green building in North America”.