Architecture professor Charles Culp, who studies residential and commercial buildings’ energy efficiency, literally takes his work home with him.
“My wife and I built an experimental house that we are living in,” said Culp, holder of the Mitchell Professorship in Residential Design. “I believe I need to live inside the research I do to truly understand and feel how things are working. Simulations are great, but the answers they give can have a pretty wide error range.”
As the innovator and designer for the home, Culp envisioned a structure that balanced energy efficiency with comfort and sustainability. As a continuous improvement project, the home’s evidence-based design incorporates common-sense strategies and proprietary technologies. Culp's wife, Bonita, recently earned a MS from the Department of Architecture studying healing gardens. She is a degreed horticulturist and has done all of the zero- water use landscaping on the surrounding lot. She also designed the interior and the atrium's interior.
“We built the house with high windows and a southern exposure to take advantage of sunlight,” said Culp. “Our home has more natural light, so we use less electricity. Energy efficiency is the lowest cost energy we can find, so we designed it with that in mind.” Careful selection of building materials, heating and air conditioning units and other appliances has delivered impressive early results.
“Energy efficiency can be measured in KBTUs, which is 1,000 British thermal units per square foot per year. Typical houses built today range from 35 to 70 KBTU per year. The American Institute of Architects say that we need to be around 14 by the year 2030,” Culp said. “Once we were in the house for several months and saw how everything was working, we made some adjustments. Now we are now running at 17 KBTU per year, so we are doing well.”
Energy efficiency is dependent on many variables, most of which can be thoughtfully influenced in new construction or improved in existing structures. Culp’s research focuses on the costliest variables — heating and air conditioning — to generate positive gains in household energy use. He credits the Mitchell Professorship in Residential Design for advancing his residential research. “About 10 years ago I began researching energy efficiency in residences,” Culp said. “The professorship provides resources that support students, innovate efficiencies and simulate the outcomes.”
Modern heating and air conditioning rely on raising or lowering the temperature of air, and mechanically moving it to where the comfort is needed. A typical home may have one or two thermostats which control the temperature of multiroom sections of the living area, resulting in heating or cooling rooms that may not be in use. To address this inefficiency, Culp is developing partial use, partial conditioned (PUPC) technology, which he hopes to implement in the house soon.
“The idea is that at any given point in the day, we may only occupy one or two rooms in our home, so why cool or heat the entire living space to the same temperature?” he said. PUPC technology facilitates the movement of cool or warm air around the living space, targeting specific rooms, based on occupancy. For example, at night bedroom temperatures can be set for comfort, while vacant room temperatures can fluctuate to increase efficiency. In the morning, bathrooms, kitchen and other day-use space temperatures can be adjusted for comfort as needed. The ability to move air from room-to-room provides other benefits as well.
Culp built an atrium in his concept house which will play an important role in both energy efficiency and in human health. In Culp’s PUPC house, air will cycle from the outside, be cooled or heated as needed and then moved into occupied space. Once the air warms above the desired temperature, it will be moved again into the atrium.
“I call it a jungle because we have so many plants,” said Culp. “The tropical plants in our atrium benefit from the slightly warmer air, which is pushed outside once it exceeds the desired range, and we benefit from living with plants.”
“Evidence-based research findings support the trend in healthcare to create medical campuses with healing and meditation gardens,” said Culp. One of the earliest studies, by Dr. Roger Ulrich, a former Texas A&M professor of architecture, looked at patients in a Pennsylvania hospital who were recovering from gallbladder surgery, which was at the time considered major surgery. The 1984 article, published in the journal Science, showed that patients whose windows overlooked trees healed, on average one day faster, needed less pain medication and had fewer post-surgery complications than those whose view consisted of a brick wall. “If plants have such a positive impact on patient recovery, why not apply their benefits to healthy people to keep them healthy?” said Culp.
In addition to the comfort and health of residents, PUPC can also aid in the health of the home itself.
In the summer, when a residential wall separates the hot and humid outside air from the cooler, dehumidified inside air, Culp says a perfect storm is brewing. “Most houses create a negative pressure in the home, which pulls outside air and humidity through the wall,” Culp said. “When the dew point and temperature inside the wall match, condensation forms, and often leads to mold growth.” Mold can cause serious structural damage to a building and jeopardize human health.
The use of PUPC positively pressurizes the house, creating slightly more pressure inside the house than out, pushing the dry air through the walls, which dehumidifies them. That helps mitigate mold growth behind sheetrock, keeping the residents and the house healthier.
“We need to change how we think about energy,” said Culp. “We must develop better strategies and technologies that can work in both residential and commercial spaces, to improve efficiencies and human health and well-being.”
Culp holds more than 40 patents, and serves as an associate director of Texas A&M University’s Energy Systems Laboratory.