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Air Sealing

Chances are, you’re already familiar with your home’s air leakage, but you may not know the culprits.

All homes have spaces or holes in the attic and gaps in the rim joists that allow unconditioned air from the outside to enter the home. This is found even in new homes that are built to code and follow higher standards. These openings cause the discomfort of drafts and cold spots in your home and increase energy use as your conditioned air escapes. Leaky HVAC ductwork, for example, is a major cause of high energy bills, that most homeowners aren't even aware of. The holes and tears in the ductwork leak the conditioned air - that you are paying so much for - into your hot attic. Similarly, the recessed can lights found in many homes are almost never sealed properly, letting unconditioned air from the attic leak into your kitchens, livings rooms and bedrooms. Not to mention the air that SNEAKS inside your home, which contains pollutants and moisture, leading to poor air quality and mold issues. 

Stack Effect - and How it Affects You

During the cold winter months, 'Stack Effect' is the most noticeable. Indoor air that has been warmed by the heating system rises to the upper areas of the house, and doesn't stop when it gets to the top floor’s ceiling. In a typical house, hundreds of gaps and cracks provide passageways for warm air to escape into the attic. Common leak locations include those recessed lights, gaps around a drop-down attic stairway and wall cavities used as electrical or plumbing chases. We call the interior air that leaks out of the house "exfiltration.” When this happens, you are not only losing the air you’ve paid to heat, but the escaping air creates negative pressure, which acts as a vacuum that causes air infiltration. Through cracks and gaps in your living space, cold outside air is sucked in. During the winter, cold air infiltration usually occurs in lower parts of the house, the basement and/or crawl space, but it can also occur around window and door framing or around electrical outlets in exterior walls.

Infared Thermal Imaging - Detects air leakage and lack of insulation ​

​ You experience the issues of Stack Effect in your house as cold drafts felt near exterior walls and in the basement. Typically you also notice that the floor surface directly above a basement or crawl space is uncomfortably cold during winter months. In the attic, evidence of air leakage can often be found on the fiberglass insulation installed over the attic floor, insulation near an air leak will often discolor from dust deposited on the fibers by rising air. These comfort problems then lead to energy problems. As heated air is leaving the house and cold air entering, your heating system has to work longer and harder to maintain comfortable interior temperatures. This leads to even higher heating bills all winter. Fortunately, having your home air sealed by professionals will effectively prevent the Stack Effect by dramatically reducing air exfiltration and infiltration. It’s especially important to seal attic air leaks, since this is where most warm air escapes in the winter. In fact, according to research by the Dept. of Energy, attic air sealing, when combined with an attic insulation upgrade, can cut your heating and cooling costs nearly in half.

​ Blower Door Test - Measures air leakage

How can we help?

During your home energy audit, VFD Contracting will determine where air leaks are occurring based on blower door testing and thermal imaging results. The Blower Door test quantifies the amount of air infiltrating the home to measure a home's air leakage. Thermal imaging can show us where large temperature discrepancies are evident, pointing to areas to focus on. Our team is highly skilled and experienced in finding and targeting even the hidden air leaks in your home and sealing them off properly. VFD Contracting’s installers are also specialized in inspecting and sealing your HVAC ductwork, preventing conditioned air from being wasted as it travels through the ducts, and helping to greatly improve the efficiency of your cooling system. With proper sealing, we also help to decrease humidity and moisture entering the home and causing mold and mildew issues. Ultimately we help prevent Stack Effect by sealing off the top of your home (attic) and the bottom of your home basement or crawlspace) to stop conditioned air leaving and unconditioned air from being pulled in.

Benefits of Air Sealing your Home:

  • Improve comfort, stopping unwanted air movement and drafts

  • Reduce heating and cooling bills

  • Keep out pollutants and contaminants that affect indoor air quality

  • Prevent condensation and moisture, which contribute to mold growth

  • Reduce your energy use by up to 20%, decreasing your environmental impact 

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