It IS Easy Being Green
October 12, 2009
Today’s media is saturated with the emphasis on green, environmentally-friendly equipment and procedures, and carbon footprint has become a household term.
Green is not only gaining increased media attention, it is becoming a standard as corporations, contractors, retailers, health care institutions, and governments promote “green buildings” into the mainstream. Consumers have started to pay attention to efficiency and conservation as the prices of home heating fuel and electricity have increased dramatically. Consumers seek guidance from industry experts on how they can build smarter or retrofit their existing homes to save energy, while helping the environment at the same time.
DESIGN CONSIDERATIONSProperly designed and installed HVAC systems provide multiple benefits for occupants, building owners, contractors, and the environment. As the consumer’s advocate in the realm of HVAC, it is the contractor’s responsibility to provide the most efficient, comfortable system possible within the customer’s budget.
Payback periods for the additional upfront investment of higher-efficiency equipment are greatly reduced with exponentially increasing fuel and electrical costs. Even if the current owner does not intend on remaining in the home a long period of time, a home with lower energy costs will stand out in the real estate market.
Proper equipment sizing plays a large role in both efficiency and comfort. “Rules of thumb” are no longer acceptable, and contractors that do not perform a proper heat loss and gain calculation on a customer’s home during retrofit or new construction are missing an opportunity to provide the best possible comfort and efficient system operation.
Today’s consumer has a wealth of information at their fingertips (only a few mouse clicks away), and many are well informed enough to understand what a heat loss and gain calculation is and will ask for the results of the calculation performed by the contractor. The Air Conditioning Contractors of America’s (ACCA’s) Manual J has become the standard for residential load calculations, and there are PC-based applications that simplify the load calculation process.
Equally important is proper duct sizing and application. Duct selection with ACCA Manual D ensures that ductwork is selected appropriately for actual room-by-room requirements. Supply and return ductwork should be sealed with mastic. Sealing the supply duct prevents spillage of conditioned air into a nonconditioned space, and sealing the return duct prevents pulling unconditioned air (such as superheated attic air) into the system. Duct tape is not recommended, as it has a tendency to dry over time, losing the ability to provide a good seal. Insulation reduces energy loss through ductwork, particularly in unconditioned spaces such as attics and crawlspaces.
Air filters are critical for proper function of the indoor coil. Insufficient filtration results in reduced efficiency and reduced comfort. Filter efficiency is rated on the Minimum Efficiency Reporting Value (MERV), which is a scale from 0 to 20. Higher MERV-rated filters provide higher filtration capability, and with this comes higher resistance to airflow. Filters with MERV ratings higher than 12 should be used only when the air distribution system is designed to accommodate the increased restriction.
VENTILATION AIRTightly sealed homes in today’s new construction are an integral part of the overall system efficiency. The efficiency of older homes is improved through careful discovery and sealing of all openings that allow continuous air passage between the indoor (conditioned) air and outdoor air.
Heat recovery ventilation systems provide air exchange with the outdoors without exhausting the tempering from the exhausted indoor air. Heat recovery ventilators reduce the costs of heating ventilated air in the winter by transferring heat from the exhausted indoor (warmer) air being exhausted to the incoming (cooler) air from the outdoors. In the summer, the exhausted (cooler) indoor conditions the incoming (warmer) ventilation air to reduce ventilation cooling costs.
GREEN SERVICE CONTRACTINGAt the contracting service level, there are many green possibilities. Consider the following:
• Online technical training and documents reduce waste created by hardcopy manual printing and shipping, as well as providing the latest, up-to-date technical content with no fuel consumed in creation or delivery.
• GPS technology brings technician dispatching to an art form. Service vehicles are efficiently routed without excessive unnecessary mileage. This results in reduced fuel consumption and carbon emissions, while increasing the technician’s effectiveness and the level of customer service.
• Service vehicles must be maintained on the manufacturer’s recommended schedule to maximize efficiency and minimize emissions.
• Paperless recordkeeping eliminates paper waste and reduces record storage requirements, while making record access a snap.
• During air conditioning service, proper leak detection methods must be performed on every installation prior to opening the outdoor unit service valves. This has always been proper service practice, and is especially important in the green world, keeping refrigerants out of the atmosphere. There is no refrigerant made past, present, or future that can harm the environment if it is contained within the system.
• Recovered refrigerants, refrigerant oil, and vacuum pump oil must be responsibly disposed of.
• Installed systems, no matter their efficiency, cannot perform as designed without proper installation and setup. Technicians must ensure the systems are located, piped, evacuated, and charged exactly per the manufacturer’s recommendations.
• Proper furnace installation and setup will minimize fuel utilization and ensure that the fuel is burned as completely as possible. Complete combustion is almost impossible to achieve, but careful attention to quality and quantity of combustion air and gas (or oil) pressure will minimize harmful byproducts that are exhausted outdoors. In complete combustion, the fuel burns with oxygen from the combustion air, producing a limited number of byproducts. When a hydrocarbon burns in oxygen, the reaction will only yield carbon dioxide and water.
• Maintenance is the final piece of an efficient HVAC system. Biannual maintenance by a qualified technician is recommended to keep the system operating as intended. The customer must be educated as to filter location and replacement, as well as maintenance requirements to keep their comfort investment operating as designed. Proactive service companies offer prepaid service contracts, which reduce costs while ensuring the system receives the proper maintenance.
• Equipment boxes and pallets should be recycled rather than thrown in the trash.
GREEN AND LEANGoing green does not have to be extravagant or costly. From a service standpoint, green is simply reinforcement of accepted “best practices” for service and installation, while introducing new technologies into the mix.
The green approach to service contracting has many benefits, including reduced environmental impact, increased technician productivity, and customers that will provide positive referrals. Whoever said “It’s not easy being green”?
Publication date: 10/12/2009