R-value (insulation) typical straw bale houses have very thick walls and thus are well insulated. Snow is roughly R-1 per inch. Brick has a very poor insulating ability at a mere R-0.2 per inch; however it does have a relatively good thermal mass. Note that the above examples all use the U.S. (non-SI) definition for R-value. When determining the overall thermal resistance of a building assembly such as a wall or roof, the insulating effect of the surface air film is added to the thermal resistance of the other materials. In practice the above surface values are used for floors, ceilings, and
Air Quality Egg different versions; depending on what customers choose, the egg can measure Particulates (PM10, PM2.5 and PM1.0), CO2, NO2, SO2, ozone, carbon monoxide and/or Volatile Organic Compounds. The Particulate version detects particles as small as 0.3µm (microns), using two Plantower PMS5003 sensors. The PM2.5 measurements of the Air Quality Egg version 2 had an R² correlation factor of 0.79 to 0.85 with a professional reference sensor, in a field test run by the Sout Coast Air Quality Management District (an R² approaching the value of 1 reflects a near perfect correlation, whereas a value of 0 indicates a complete lack of