The business of school air conditioning
When a classroom is sweltering, nobody is productive. More and more teaching days are being lost to hot, humid weather even though there is a way to mitigate the problem: air conditioning.
The challenge is justifying the cost of installation and maintenance at a time when competition for budget money is fierce. The place to begin is understanding the positive impact that AC has on all the critical elements of academic success.
Multiple studies show that cooler temperatures in a classroom improve focus and productivity. Removing the C02 by ventilating buildings with fresh, outside air aids concentration and retention. Students in air-conditioned schools also have scored higher on tests.
Enough schools have added air conditioning to existing buildings and included it in new construction that choosing the right cooling and ventilation system doesn’t have to be a guessing game.
AC system options
Budgets tend to be the dominant factor when choosing a system. But the prices of equipment and installation aren’t the only considerations, says Steve Yurek, president and CEO of Air-Conditioning, Heating, and Refrigeration Institute, a trade association.
Classrooms with south-facing windows that have sun streaming in all day have different needs than windowless gymnasiums or north-facing administration offices. To identify the unique needs of any building, Yurek suggests walking through the building with potential contractors and reviewing blueprints prior to construction.
Tips to cool down
Education and HVAC professionals offer the following ideas when considering an air conditioning installation:
Plan aheadÑdon’t wait for a disaster, such as a system failure, because that limits your options.
Find funding. Health and safety budgets are the best sources for funding an air conditioning installation.
Evaluate the entire building before doing anythingÑelectrical infrastructure, plumbing, mechanical systems.
Know the laws. Study your own state and local requirements to finance projects and hire contractors.
Be wary of contractors offering a single-system recommendation as “the only thing you need.” That usually means it’s the only system they wants to sell you, as opposed to what your building actually requires.
Review specifications with maintenance staff and note that systems available are highly technical. Most staff members who are not HVAC-trained will not be able to properly assess and adjust systems operations to maximum efficiency. If in-house staff members lack the expertise, add a service package.
Make an all-inclusive budget. Include building repairs, maintenance and staff training to ensure those using the system understand it and know how to use and maintain it properly.
A good contractor will ask administrators lots of questions about their cooling goalsÑthose who don’t should be eliminated from consideration. And beware of anyone who offers only a single solutionÑthere are many options. They generally fall into three main categories, says Francis J. Dietz, vice president of public affairs for the Air-Conditioning, Heating and Refrigeration Institute.
Individual units: These can be window air conditioners or free-standing floor units. These are the least energy-efficient of all AC options. Other issues include possible distractions when repairs are required during the school day, added noise in the classroom and no air filtration or ventilation.
Lack of fresh air can raise C02 levels and recirculate allergens, and no humidity is removed, making it difficult to achieve lower temperatures.
Centralized: Most component parts of the system are in a single location, such as outdoors, attached to the outside wall or on the roof. The indoor evaporator coil and air handler are usually in a basement mechanical room, distributing air throughout the facility via ductwork.
Individual room controls can be added to address different temperature needs. These systems include controls for fresh-air intake and filtration to remove C02, allergens and pollutants from the air. But centralized air conditioning uses a great deal of energy and can be too complex for in-house staff to maintain.
Combination: A number of mechanical systems can be integrated or operated independently to address specific environmental needs in a facility, creating multiple building “zones.” These individual systems are placed throughout a facility and have their own controls.
Special attention must be paid to each system zone to balance factors such as ventilation and filtration. These systems are more complex, requiring more labor-intensive operations and maintenance supportÑin-house staff must know how to operate and address the separate maintenance schedules of each system. This added cost is partially offset by enhanced comfort and the ability to separately control different areas of the building.
Where to begin
The first step in assessing the viability of air conditioning is creating an energy model for a building ready to be constructed or an existing building, says Anisa Baldwin Metzger, district sustainability manager with the Center for Green Schools at the U.S. Green Building Council.
Resources to learn more
These organizations will help you find the information and expertise when you consider the need for air conditioning in your facilities.
ACCA is a non-profit association whose membership includes professionals and businesses in the indoor environment and energy services industry.
Air-Conditioning, Heating, and Refrigeration Institute is a trade association representing manufacturers of HVAC and certifies equipment.
Green Schools Investment Guide
National Clearinghouse for Educational Facilities (NCEF) provides timely, comprehensive information on designing, building and maintaining safe, healthy, high-performing schools.
North American Technicians Excellence (NATE) tests and certifies technicians for service and installation of HVAC systems.
U.S. Green Building Council â Center for Green Schools drives the transformation of all schools into sustainable and healthy places to live, learn, work and play, and compiled reports providing the benefits of AC in schools.
An engineer or HVAC contractor can construct a building virtually using a computer-aided design (CAD) program. This way district leaders can analyze every element that will have an effect on the successful operation of the chosen system.
Details such as window type and fit, blinds, insulation and placement of exterior doors are just some of the factors you must consider.
When the virtual building is created, myriad factors are added to replicate the exterior and interior environment. For example, the position of the building on the site identifies where and when the sun will shine through classroom windows. Other details include trees casting shadows differently during warmer months than colder months.
The impact these variables have on changing the temperature in a classroom will predict how the environment will wear on the chosen HVAC system. Planners also can identify improved efficiencies that are gained from repairing leaky windows or adding more insulation.
“Then you can see what the expected energy bills might be,” Metzger says. “If you’re trying to decide what systems to buy, it’s a lot cheaper to have someone estimate it for you than to make the wrong decision.”
The building should be considered part of the HVAC system because it must support whatever mechanical components are added, Metzger says. Contractors refer to this as the “building envelope.”
The materials specifications for windows, doors, insulation and other elements will indicate their capacity for keeping cool air in and hot air out. Architectural drawings will show the details of how these fixtures will be installed to best serve cooling purposes.
It gets more complicated with existing buildings. Generally, those built before 1960 have space between classrooms for ductworkÑmaking installation easierÑbut outdated electrical wiring. Newer buildings have solid wall construction and better electrical infrastructure.
The only way to know for sure is to walk the school to understand how it was put together, Yurek says. Because existing buildings are modified over time, and the original building plans are rarely updated with these changes, it’s necessary to verify the physical structure to avoid costly mistakes.
Many schools are using building automation systems to improve energy efficiency and reduce costly human error. This technology automates many time-consuming activities, such as adjusting thermostat settings throughout the school day.
Adding air conditioning impacts the interconnected mechanical systems, so compatibility is a must to ensure the efficient operation of all environmental controls. Will adding AC impact the heating equipment? Will the automation system work with the AC controls?
A good contractor will identify a building’s systems to ensure the component parts will work together seamlessly. For existing construction, this includes testing system operations to make sure they’re working correctly or if repair or replacement is needed.
Planning the project
After suffering extremely high temperatures in the early part of the school yearÑ90 degrees and higherÑLuther L. Heller, superintendent of Montevideo Public Schools in Minnesota, says the district decided to implement what the state refers to as a “dehumidification” project, or AC. Phase one included three of the district’s four buildings (just under $6 million). The fourth building, which was $6 million, is on the drawing board with work due to begin this summer.
Heller says one of the most important things he learned from phase one was to talk to as many HVAC contractors as possible to tap their expertise. This also allowed him to compare bid data and recommendations.
Proper installation and system tests are essential; a botched installation can make a system up to 40 percent less efficient, costing a lot more in the long run. Maintenance, of course, also is critical, says Mike Dobbs, construction project manager for Saint Louis Public Schools, which started adding AC room units 10 years ago.
Of the 78 schools in his district, most are over 100 years old. Only three schools won’t get AC because they are too expensive to retrofitÑfans and ventilation keep the schools in the mid- to high 70s during hot days. In-house staff is responsible for maintenance, but they all “learn on the job” because the district can’t afford to hire additional staff or to contract out the work to properly maintain the systems, Dobbs says.
“You can’t put in multimillion dollar systems and walk away and expect them to operate,” he says. “Financially, we’re a crisis management district. We do maintenance but it’s on a very, very minute scale. We’re making an attempt to keep our systems clean. The life expectancy of the system? It will fail earlier. That’s just the bottom line.”
Margo Pierce is a freelance writer in Cincinnati, Ohio.