HVAC Duct Insulation Makes a Difference
by Suresh Patel, Senior Mechanical Designer
The majority of today’s commercial and residential heating, cooling and ventilation systems rely on centralized HVAC units and sheet metal ducts to effectively achieve thermal comfort. While this is the industry standard, it is important to note that heating, cooling and ventilation together account for approximately 60% of energy usage in commercial buildings. In residential buildings, about 45% of the energy goes to heating and 12% to cooling. While energy/electrical usage for heating and cooling varies among climate zones, they remain, by far, the largest categories on a building owner’s utilities invoice.
These statistics take on even greater weight when we consider the broader environmental issues of sustainability, lowering our dependency on fossil fuels, reduction of greenhouse gases, and development of alternative and renewable sources of energy. According to the U.S. Department of Energy, commercial and residential buildings use 38% of all energy in the U.S. and 76% of the electricity.
It stands to reason, then, that it is critically important to pay attention to the energy and utilities usage of commercial and residential buildings and to take steps, whenever possible, to increase efficiency. One key way to achieve this is to insulate HVAC ducts — in both commercial and residential buildings. Along with energy and environmental impacts, this practice produces other benefits.
Five Benefits of Duct Insulation
Decrease energy bills. Insulating your ductwork enables conditioned air — both warm and cool — to discharge into a room at the proper temperature, creating less work for your HVAC system and reducing your utility bills. Without duct insulation, the conditioned air inside your ducts will be affected by heat gains and losses from the indoor environmental conditioned air.
Increase comfort. Uninsulated ductwork wastes more than 20% of energy by the loss of heated or cooled air through conduction. Insulated air ducts are more efficient in retaining the temperature of the air they are transporting, reducing energy waste. The air that reaches you is closer to the temperature you desire, making your living space feel much more comfortable.
Help the environment. Insulated air ducts eliminate heat loss by conduction, enabling the HVAC system to maintain a comfortable temperature while reducing energy usage. This benefits the earth’s environment and greatly reduces your carbon footprint. It is also worthwhile to bear in mind that generating electricity is expensive. Many factors influence the cost, such as the price of fuels used to produce energy, power plant expenses, power transmission losses, weather conditions and regulations.
Prevent condensation and stop the formation of mold and fungus. Over time, air ducts can develop problems with condensation and water leaks, which may lead to the growth of fungi, mold, mildew and other microbes. Exposure to these microbes can cause health issues or complicate existing health conditions. Insulation minimizes condensation around air ducts, reducing the chances of mold, mildew or fungus growth in the periphery of the ductwork.
Reduce indoor noise. As air travels through ductwork, it can produce all sorts of odd noises, such as rattling, buzzing or whistling. In the winter, metal ducts can expand as heated air travels through them, and they may contract when the system is off. This expansion and contraction can cause popping and creaking noises. Duct insulation does not eliminate these sounds, but it acts as a damper that can greatly reduce the volume of air-generated noise.
Getting It Right
All HVAC units must comply with equipment efficiency requirements mandated by energy codes, while sheet metal duct construction and installation must comply with the guidelines of the Sheet Metal and Air Conditioning Contractor’s National Association (SMACNA) and the applicable energy code when it pertains to duct insulation. Specially trained engineers, such as the experts at CoolSys Energy Design, can help to ensure that your HVAC installation or retrofit project meets all of these specifications and standards.
About the Author
Suresh Patel, a Senior Mechanical Designer at CED, has nearly 25 years of experience under the leadership of Allan and Clive Samuels. With a diploma in engineering from Vapi, India, he has been designing systems for heating, ventilation and air conditioning for decades. Suresh leads the Princeton office’s department on mechanical design and enjoys mentoring up-and-coming engineering students on HVAC systems in supermarkets and retail centers. When he is not nurturing young minds, he enjoys gardening, travel and spending time with his family.