Friday, March 19, 2010

Energy and Sustainability

Thermal insight

Early last Friday morning, Nick Marcyan of Interface Engineering , visited the Manley residence with a Fleer Thermal Imaging Camera to provide this architect with some additional insight and education on heat loss and the benefits of thermal insulation and infiltration control.

 
A rainy Friday morning, Nick unpacked the camera, and gave a brief, rain-free demonstration inside the house. Warm air curling out of a floor diffuser looks like flames in a fireplace. The insulating value of a standard poodles’ curly coat is impressive – our dog, Pepper, appeared royal blue as he walked through the cameras’ field of vision. The Fleer camera allowed Nick to pin-point surface temperatures within the image, and records the full range of temperatures in the image from low to high – lowest being dark blues and highest being bright reds.

Outside, under a light but steady rain, we began a walk-around. Outside air temperature was about 40 degrees. The thermal image results were telling. My prime concern was infiltration points from the basement and from aging double-hung windows at the older, un-remodeled areas of the house.


The first image that provided a surprise was of the building’s west wall at the kitchen/dining room area. During a remodel several years ago, a space that was originally a bedroom was remodeled into the kitchen. The existing lath and plaster in that room was stripped for access to studs for installation of new plumbing and electrical. The 4” nom studs at the kitchen exterior wall were insulated with R-19C batt. Adjacent spaces remained un-insulated. The Fleer image clearly shows the line between the insulated kitchen and the un-insulated dining room – a source of heat loss that won’t be corrected any time soon.

Nick, raising the camera to trace the line of the eaves and roof, surprised me with the assessment that my ceiling insulation, 12” of loose fill, was sound with no significant heat loss sources showing. Windows in the remodeled or added areas of the house are 14 year old Insulate Industries vinyl sash, insulated double hung, casement and awning windows (recently purchased by CertainTeed). This glass showed good retention of insulating qualities. Thermal images of these windows showed red at the window perimeter where window frame, glass and glass spacer all meet.

Andy Frichtl of Interface Engineering has explained that even new insulated glass units can be a trouble spot in heat loss. Through their commissioning work and efforts to achieve LEED ratings or net-zero energy/water/waste use in their projects, Interface has discovered that glass units in new job sites will often include units lacking argon gas. This creates a vacuum in the glass unit’s air space, causing the inner and outer panes of glass to touch or nearly touch at the center. In a thermal image, this phenomenon shows up as a corona like spot in the center of the pane known as a "thermal signature".


The 90 year old wood sash windows showed significant heat loss as expected. Interestingly, the tendency for heat - trapped between the storm window and the interior sash - to “rise” is readily apparent in the thermal image; shades of red gradating to a cooler yellow from the top of the upper pane to the lower.
Images of the foundation also proved out suspicions that the un-insulated concrete at the basement and crawl-spaces is a significant problem area.

For me, the lesson is that I need to complete work at my basement to insulate the concrete basement walls and isolate and insulate the crawlspace areas. Phase two: window replacement in older areas of the house. Not exactly zero energy use, but a step in the right direction.

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