Literal question
13. Which fuel is used most for heating this house, apartment or mobile home?
[] Gas: from underground pipes serving the neighborhood
[] Gas: bottled, tank or LP
[] Electricity
[] Fuel oil, kerosene, etc.
[] Coal or coke
[] Wood
[] Solar energy
[] Other fuel
[] No fuel used
Interviewer instructions
13. Mark the category for the fuel used most to heat your house, apartment, or mobile home. In buildings containing more than one apartment, you may obtain this information from the owner, manager, or janitor.
Solar energy is provided by a system that collects, stores, and distributes heat from the sun. Other fuel includes any fuel not listed separately, such as purchased steam, fuel briquettes, and waste material.