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Energy Upgrade Case Study in Portola Valley

 A successful home performance retrofit!

Energy Beyond Design: A Retrofitting Example in Portola Valley

Age of Home: 60 years
Issues: Moisture, room to room temperature variation, high electric & gas bills (even with solar PV), and draftiness.
Solutions: Whole-house air sealing, duct sealing, insulation, crawlspace vapor barrier
Results: A more comfortable home with better indoor air quality and lower utility bills. Air infiltration rates reduced by 50%, duct leakage reduced by 66%, humidity significantly decreased in crawlspace.

1

The Energy Beyond Design assessment and retrofitting team prepares to run a blower door test and review the initial test results. 2890CFM50 is the amount of air leakage in cubic feet per minute (CFM). We test every home before and after we perform work, this is known as “test-in” and “test-out” so that we can quantify the improvements we’ve made and ensure that we have the home performing at an optimal level.

Many of the places that air escapes/infiltrates a house are the last places one would expect; crawl spaces, attics, in walls around pipes or through electrical outlets. We use a blower door to pull air out of a house, allowing us to measure how many air exchanges the inside of the home with have with the exterior air. Why is this important? When you use energy to heat or cool a house, the last thing you want is to lose that costly conditioned air through these holes in the buildings envelope.

2

We ran our blower door in conjunction with an infrared (IR) camera to find the locations of air infiltration and poor insulation behind walls. The photos above show that huge amounts of hot air were seeping in from the wall cavity through the slits in the medicine cabinet (left) and around the window (right). To remedy this situation, we removed and sealed the medicine cabinet, sealed the wall behind and sealed around the window’s trim.

3

The IR photo above shows heated areas on the ceiling beams due to air leaks. Through a visual inspection of the home, we found a 1/2 inch hole behind the return air grill that was pulling air straight from the fiberglass insulation filled attic – and then distributed the air behind the filter into the furnace where it was blown throughout the entire house.

4

The attic is a huge air infiltration area and thus the enemy of your wallet and your respiratory system. Above you see that we peel back insulation fill all the holes (left), cracks, gaps and seems and then blow in more insulation (right) to get the attic to the ideal R-factor (insulation level) for this home which was R-38.

6

Above are a few of the several dozen areas we found around pipes, wires and ducts that allowed the damp contaminated air from the crawl space to enter the living space above.

8

In addition to the mushrooms and the dozen or so black widows that made the crawl space their home, we also found strange worms (lower left) crawling around. In the previous home we retrofitted, we had to evacuate a messy family of raccoons that had made the crawl space their home (and toilet).

10

Because this client had moisture issues in her house, we also put down a vapor barrier to prevent the majority of moisture from infiltrating into her home.

We were very proud that this particular retrofit reduced air infiltration by nearly half which means the client’s home is now much better at retaining conditioned air. We also reduced the air leaking through the ducts by 66% which means that a lot of money she was spending to deliver heat to the crawl space and attic is now going to its intended locations.

As a result of the retrofit, our client has cleaner air circulating through her home which should cut down on allergies and illness. Air infiltration sealing and improved insulation better contains heated or cooled air, improving comfort. And finally, with all of the upgrades working in unison, her retrofitted home requires less heating and cooling, saving money on utility bills and reducing her carbon footprint.