Promises of energy efficiencies in residential construction attract a great deal of attention. But, new construction, retrofitting, remodeling, and expanding public buildings continues apace on Martha’s Vineyard, despite national and global financial stress. The Martha’s Vineyard Times asked Marc Rosenbaum, a new addition to the South Mountain Company specializing in engineering energy efficient buildings, to discuss the energy-saving possibilities for new public building construction.
By Marc Rosenbaum
Drill, baby, drill may have been a popular rallying cry in some circles in the last election, but the Deepwater Horizon catastrophe focused our attention on the risks we routinely accept to satisfy our energy needs. As is true in much of rural New England, Martha’s Vineyard depends on oil for both transportation and for much of its building heating energy, so we are doubly vulnerable to both price instability and shortages. After 20 years of providing energy and systems-consulting to South Mountain Company, I’ve recently moved to the Island from rural New Hampshire and joined forces with South Mountain. My town, Plainfield, N.H., experienced the 2008 oil price shock especially hard as a shortfall in our K-8 school budget. In the fall of 2008, I worked with the volunteer facilities committee to develop an approach for the school that would demonstrate profound energy savings and remediation of serious deficiencies at the same time.
The Plainfield School was built in 1972 and added to in 1989 and 2000. In addition to high energy usage, it suffers from wide temperature variations, drafts, moisture, and air quality problems, and noisy mechanical systems (much like the Chilmark School, which was built in 1998). We proposed to the School Board to take one 900-square-foot corner classroom and disconnect it from the oil-fired heating system, remove the noisy ventilator, and replace these with an air source mini-split heat pump to provide heating (and cooling occasionally) and a residential scale energy recovery ventilator to supply fresh air. We proposed a radical insulation upgrade, adding 3 inches of foam insulation to the foundation, 6-1/2 inches of foam insulation to the walls, and replacing the windows with quad-glazed windows that have double the insulating value of typical new windows. The roof insulation had been previously addressed. In the process of this Deep Energy Retrofit, we would also make this room far more airtight, and install new, durable siding on the walls. With the Board’s blessing, we asked the School District voters to approve a warrant article to fund what we called the Prototype Classroom, as a model of what we might achieve across the entire school in years ahead, and as a path to improving the users’ experience while ultimately freeing the town’s largest asset from the unpredictability of oil prices. In March 2009 the voters approved the expenditure, and during the summer of 2009 the work was done and the Prototype was ready when school re-opened.
The classroom was equipped with energy meters to measure the energy used by the ventilation system and the heat pump and data loggers to track classroom temperature, relative humidity, and carbon dioxide levels as a surrogate for indoor air quality. We also kept close contact with the room’s users. The differences both measured and experienced were profound. The room was dramatically more comfortable, quiet, and well ventilated than its counterparts. Relative humidity was in the comfort zone of 30-35%, much higher than the rest of the school. After-hours teacher meetings tended to gravitate to the Prototype Classroom because it was quiet and comfortable.
The measured data showed that the heating cost per square foot for the prototype was about 90% less than the rest of the school! When the total annual energy usage for heating, cooling, ventilation, lighting, and plug loads was projected from this data, it appeared that the prototype could achieve Zero Net Energy — all energy used annually offset with on-site renewable energy — with a two-kilowatt solar electric system. If we imagine extending these savings to the rest of the Plainfield School, it’s possible this school could achieve Zero Annual Net Energy with a 75-100 kilowatt solar electric system, costing perhaps $450-600,000. This seems like a big number, yet compare this to an annual energy cost of about $80,000 for the school — a number that no one believes is likely to go down in the future.
The Facilities Committee and the School Board went back to the voters in March of this year for a bond to extend the Prototype Classroom approach to the balance of the 1989 building this summer. With 77 percent voting in favor, the bond passed, and this work is currently in progress.
The example of the Prototype Classroom is garnering attention due to its radical energy savings, but focusing only on energy loses sight of the integrated solution that addressed energy, noise, air quality, moisture, and comfort together. The approach used can be accomplished in phases, as the town can afford it. The educational value for the students is immense, and the performance has become a source of pride in the town.
A community has come together to upgrade its school and secure its benefit to the town for the future. There’s no reason this can’t happen here on Martha’s Vineyard, too, and especially no reason why new buildings built by the towns (and others) can’t be made with similar high performance standards.