Improve Your Air Conditioner HVAC Performance
Donna Gilmore
NAHB CGP
NAHB Accreditted Verifier
Sigler Construction Inc.
Email: donnagilmoresc@yahoo.com
Phone: 843-681-7457
Leaking ducts can reduce your heating and cooling system's energy efficiency byby 10 to 30 percent. Imagine, one third of your heating-bill money may be going to waste.
In most homes built before 2008 on Hilton Head Island, SC the HVAC duct work is located in the unconditioned attic space. If the supply ducts are leaking, heated or cooled air is forced out unsealed joints and lost. In addition, unconditioned air can also be drawn into return ducts through unsealed joints. In the summer, hot attic air can be drawn in, increasing the load on the air conditioner. Ducts located in the unconditioned attic space presents a number of additional problems for homeowners; it tends to be difficult to inspect the HVAC duct work for leaks and tears, the extra cost that leaky ducts add, they also reduce the quality of your indoor air. The leaks pull dust, mold, carbon monoxide, methane and allergens into the hvac system.
What are the health consequences of poor indoor air quality? The most common symptoms are irritation of the eyes, nose, throat, headaches, fatigue and dizziness. Usually, these symptoms go away when the person is no longer exposed to the irritants.
But it is also possible to develop long-term chronic conditions and diseases like asthma, hypersensitivity pneumonitis and humidifier fever. Other health effects won't even be noticeable till years after the exposure: Respiratory disease, heart disease and cancer. It is extremely important to keep your indoor air quality healthy.
Solutions offered by Sigler Construction:
2. Developed by Sherwin-Williams, E-Barrier™ Reflective Coating helps reduce utility bills for homes and commercial buildings.
When applied to any attic roof decking or to previously painted commercial decking, the microscopic metal particles in E-Barrier Reflective Coating help maximize energy efficiency.
- In summer, E-Barrier™ reflects radiant energy from the sun
- In winter, E-Barrier™ prevents radiant energy from leaving the building
- Reduces heating an cooling costs by as much as 30% percent right away
- Low emissivity (virtually no odor)
- Breathable coating, won't trap moisture or destroy your roof decking
- Save Hundreds with E-Barrier™ instead of costly blown-in insulation that only deteriorates within a few years
E-Barrier Reflective Coating helps keep the interior of structures warmer in winter and cooler in summer by reducing the loss of radiant heat in the winter and reducing the penetration of heat into a building in the summer.
E-Barrier Reflective Coating contains specialized materials which reflects radiant heat back towards its source. in the winter, about 65% of a buildings heat that would normally escape through the roof surface is reflected back into the building, reducing the loss of heat. In summer, about 63% of radiant energy from the sun is reflected back reducing the pick up of heat (idle hot air) in the building.
*E-Barrier is certified by the EPA as a top leader in insulating products and as a Green Seal Certified Product.
3. Installing spray foam insulation in your attic rafters provides a cool, sealed attic space for your air conditioning system & air ducts to work much more efficiently. They run more efficiently & last longer with lower maintenance costs because they will now be operating in a semi-conditioned space instead of a blistering 140 degree environment. This also gives you a comfortable storage space instead of a suffocating nightmare.
Why Is Duct Leakage Important? Leaks in forced air duct systems are now recognized as a major source of energy waste in both new and existing houses. Studies indicate that duct leakage can account for as much as 25% of total house energy loss, and in many cases has a greater impact on energy use than air infiltration through the building shell. Just as important, duct leakage can prevent heating and cooling systems from doing their job properly, resulting in hot or cold rooms, and humidity problems. Worse yet, duct leaks can create air quality problems by pulling pollutants and irritants directly into the house.
Here are just a few of the problems resulting from duct leakage:
- Leaks in the supply ductwork cause expensive conditioned air to be dumped into the attic, crawlspace or garage instead of into the house.
- Return leaks pull outside air (hot in summer, cold in winter) into the duct system reducing both efficiency and capacity. In humid climates, moist air being drawn into return leaks can overwhelm the dehumidification capacity of air conditioning systems causing homes to feel clammy even when the air conditioner is running.
- Heat pumps are particularly susceptible to comfort complaints from duct leakage, especially during the heating season. Duct leaks can cause the air coming from heat pumps to feel luke-warm or even cold during the winter. In addition, leaky ductwork has been found to greatly increase the use of electric strip heaters in heat pumps during the heating season.
- Leaks in return ductwork draw air into the house from crawlspaces, garages and attics bringing with it dust, mold spores, insulation fibers and other contaminants.
- Household depressurization from duct leaks and imbalanced duct systems can cause spillage of combustion products (from furnaces, water heaters and fireplaces) into the house.
Measuring Duct Leakage
A duct leakage performance test involves pressurizing the duct system with a calibrated fan and simultaneously measuring the air flow through the fan and its effect on the pressure within the duct system. The tighter the duct system, the less air you need from the fan to create a change in duct system pressure. Testing procedures can be set up to measure only duct leaks which are connected to the outside, or to measure total duct leakage (i.e. leaks connected to the outside and inside of the house). Duct leakage measurements are used to diagnose and demonstrate leakage problems, estimate efficiency losses from duct leakage, and certify the quality of duct system installation.
Two different types of performance testing systems are used to measure duct leakage; a Duct Blaster® and a Blower Door.
Duct Blaster®
- A Duct Blaster is used to directly pressure test the duct system for air leaks, much the same way a plumber pressure tests water pipes for leaks.
- The Duct Blaster fan is first connected to the duct system at the air handler cabinet, or a return grille. After temporarily sealing all remaining registers and grills, the Duct Blaster fan is turned on to force air through all holes and cracks in the ductwork.
- The fan speed is increased until a standard test pressure is achieved in the duct system. A precise leakage measurement is then made using an airflow and pressure gauge connected to the Duct Blaster system.
- Estimates of efficiency losses from duct leakage can then be made from the leakage measurements.
- A theatrical fog machine can be used along with the Duct Blaster to inject a non-toxic fog into the duct system to visually demonstrate the location and extent of leakage in the ductwork.
Blower Door
- The Blower Door is a whole house testing system which indirectly measures duct leakage by pressurizing the entire house to a standard testing pressure.
- By comparing the whole house test before and after all registers are temporarily sealed, the Blower Door provides you with an estimate of duct leakage to the outside.
- With the Blower Door running, duct leaks can be pinpointed using a hand-held smoke puffer, or a leak detection tool called a pressure pan.
- In addition to diagnosing duct leakage problems, the Blower Door can identify building envelope improvements that will reduce energy use and increase comfort.
- Blower Door airtightness measurements can also be used in HVAC equipment design and sizing decisions, and to help estimate the need for mechanical ventilation.
Posted in: on Sunday, August 16, 2009 at at 12:56 PM
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