Heating equipment breakdown. Statistics are shown for housing units occupied by the householder during the winter prior to the interview and refer only to the main heating equipment. The data are classified by whether the housing unit was uncomfortably cold for 24 hours or more, the number of times equipment breakdowns occurred lasting six hours or more, and causes for the breakdowns. The heating equipment is broken down if it is not providing heat at its normal heating capacity through some fault in the equipment.