When we at Great Oak rented an infrared camera to try to find sources of heat loss in winter in our Common House, we took the opportunity to also do a “study” of the exteriors of our other buildings to try to find any surprising sources of heat loss. A set of pictures of each unit were provided to the owners. Here are some interesting things that were noted:

• the temperature range of the picture is shown at the bottom with the corresponding colors — dark is coldest, yellow to white is hottest — so for outside pictures, you want to find the bright spots that show heat leaking from your home,
• as far as possible, I tried to take the pictures at night, without including the sky to reduce the range of temperatures and thereby constrain the color  variation to make local details more visible — if the sky is included it will show up as “-40″ at the low end…like this: 
  
• unfortunately, on bright days, concrete porches absorbed a lot of heat and radiated it back out during the night, overwhelming the image and reducing the detail, so I took some more pictures during the day hoping to do it before the sun hit the home or caused large reflections on the windows, but not always successfully - here are some taken at night (the timestamp on the second picture is wrong) after a bright (but not necessarily warm) day;
  
   
  
• likewise, bright portch lights also can overwhelm the image
  
  
  
• exposed cement foundation is a major source of heat loss — it conducts heat from your house all night long and in summer gets heatedup and conducts the heat into your house, so if the dirt is scraped away, put it back, and as you can cover it up
  
• you might see “sideways” plumes of heat, that is the exhaust from your water heater, or single large bright circles are typically the furnace vent;
  
  
  
• note the kitchen fan exhaust venting heat
   
  
• there might also be reflections of sunlight or my reflection in windows that minorly distort the true contrast               
  
  
• chimmneys seem pretty well insulated, though I couldn’t hover above the roofs to really see the heat loss from above
  
• double basement doors are terribly leaky in all cases
  
  
• in general, as can be expected, doors and windows were the major cause of heat loss; thick curtains/blinds really do work to insulate your home and probably are the best investment we can make (note the blind on one side of the upstairs window)
  
• the rear of the units were harder to photograph as they were on a slope, or had a fence or there wasn’t much room to get far enough back
• although building roofs routinely show a gap in the insulation between units during snow melt, the heat loss wasn’t significant enough to show using the IR camera
  
  
  
• and lest you think it wasn’t fun or funny