<html><head><meta http-equiv="Content-Type" content="text/html charset=iso-8859-1"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi All:<div><br></div><div>Building on Desert Dave's note here, we've measured bale walls as having a 12-hour time lag of thermal transfer from the surfaces to the middle of the bale, thus creating a perfect foil to most diurnal temperature swings. Attached is page 4 from a report a researcher and I prepared on the Real Goods Showroom, with discussion of the bale walls and graph showing a beautiful purple line of the center of bale temperature directly opposing the other ones. We concluded that the straw bales are performing not only as insulation but also as an element having heat capacity, aka thermal mass. </div><div><br></div><div>On the days of this test, in autumn, the outdoor temperatures ranged from 36°C (97°F) during the day to 10°C (50°F) at night, while indoor temperatures at the surface of the bale walls ranged from a comfortable 26°C (79°F) during the day to 19°C (66°F) at night. Meanwhile, the center of the bale wall measured 21°C (70°F) during the day to 24°C (75°F) at night.</div><div><br></div><div>Worthy of note is that this building features a 50mm to 75mm (2" to 3") interior finish coating of PISE (a spray-applied form of stabilized earth) and up to 100mm (4") on the exterior, and both surfaces have relatively rough textures. The building also has high ceilings so the warmest air stratifies near the ceiling, and at night clerestory windows are opened to flush the space with cool air. You'll note in the graph that interior temperatures at a 3m (9') height, just above the bale walls, had wider temperature swings. </div><div><br></div><div>In any event, I think it just furthers the agreement that ample thermal mass within a good insulating envelope is a good thing, and straw bale walls with any kind of finish do this better than just about any other wall system. </div><div><br></div><div>Ride On!</div><div><br></div><div>David A.</div><div><br></div><div></div></body></html>