Blue bars show the range of outdoor (north side; Hobo 23) temperatures on each day; red bars show the corresponding range of indoor temperatures (mean of Hobos 2 and 6; range of data < 5% of total). Percentage numbers give the ratio of indoor range to outdoor range x 100%.
Strikingly, the range of indoor temperatures diminished from 57% of the outdoor temperature range (with an absolute indoor range of 5.25°F), in the absence of bricks, to only 37% on the day of brick addition (absolute indoor range = 4.25°F). Subsequent days saw reductions in the range of indoor temperatures to as little as 16% of the outdoor range, corresponding to an absolute range of only 2.25°F.