The Table 1 column-2 estimate -0.224 (0.038), n=139,343, is the specification with year-built dummies that the authors headline in the results text (rounded to -0.22) and benchmark against Ito (2010); the alternative without year-built dummies (-0.194) is mentioned only as a robustness aside and was not coded. || "We estimate an elasticity of electricity prices at the time of construction of −0.22." (p. 90, printed page)
Costa, D. L., & Kahn, M. E. (2011): 'Electricity consumption and durable housing: understanding cohort effects.' American Economic Review P&P, 101(3), 88-92.