PATH - A Public Private Partnership for Advancing Housing Technology
PATH Case Study
Delivering Measurable Gains
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"We used a series of tests from the Building Performance Institute and found the problems. First, we checked gas lines for leakage, measured the carbon monoxide output of all the home's combustion appliances, and assessed the vent pressure. We also did a visual inspection and heat loss calculations of the siding, foundation, roof, ceilings, walls, windows, and doors to find out what areas needed the most attention. Then we did a blower door test and depressurized the house to negative 50 pascals. That created a negative pressure in the home that emphasized any points of air infiltration around windows and doors. We sectioned off individual rooms and crawl spaces, then used a second manometer to take pressure readings to determine specifically where the house was leaking the most air."
The cost of Lotesto's services depends on the upgrades that homeowners choose. Clients who hire Lotesto to perform diagnostic testing pay about $400; those who use him to perform the recommended upgrades receive the diagnostic testing for free.
The cost of the upgrades to Howard's home was about $2,500 dollars; Lotesto estimates that they will save the client $700 a year on his energy bill.
"We discovered that all the contractors who had worked on his home had missed the key areas of air infiltration. A house that is properly air sealed will replenish far less than half of its air in the space of an hour. Howard's was letting in outside air at over three times this rate. Although he used good products and experienced contractors, they didn't use the right diagnostics or building science to determine the true cause of the home's problems."
[IMAGE: Blower door testing and air infiltration testing.]
"Luckily, there were still ways that we could help him by improving the air sealing and insulation in many areas of the home. Our approach is to seal all the places that let air in, especially the crawl spaces, foundation, and the attic, which are more likely to let contaminants and dust into the home. If necessary, we will install a mechanical air supply such as a fan above ground to filter the optimum amount of fresh air into the home."
"The correct amount of air will vary according to the size of the home and the number of occupants (including pets). In addition to lowering utility bills, air sealing also makes the air in the home cleaner and healthier because air is the number one carrier of moisture and bacteria."
DIAGNOSE BEFORE PRESCRIBING
"Our method is similar to a medical approach," Lotesto says. "Much like a doctor, we start asking questions to determine symptoms. A house is a group of systems that are working side by side.
If you address one of those systems, it may affect another. If someone is trying to save on their energy bills, going in there and saying, 'I'm going to change all of your windows and it will automatically save you a bundle' is kind of ridiculous. You need the house to tell you what it needs first."
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Content updated on 9/1/2006
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Affordable Housing Providers