|Number of households by year of construction|
|1950 – 1969||1970 – 1979||1980 – 1989|
|Dwelling has an attic|
|Dwelling has an insulated attic|
|Yes - on the attic floor||1,185,114||A||1,025,160||A||867,367||A|
|Yes - on the attic walls||–||U||–||U||–||U|
|Yes - on both the attic floor and walls||132,151||A||143,830||M||123,009||A|
Note:Due to rounding, the numbers may not add up and may differ slightly among tables.
The letter beside each estimate classifies its quality as follows: A–Acceptable, M–Use with caution, U–Too unreliable to be published.
Source:2011 Survey of Household Energy Use