Propane provides energy for household appliances such as water heaters, ovens and furnaces and generates energy for refrigerators and air conditioners that does not rely on delivery from a remote location. It is the logical energy choice for rural areas and areas that experience frequent outages or high prices for other systems. The on-site propane tank also guarantees the availability of energy to run a generator to power a furnace during power electricity outages or interruptions in natural gas supplies.
Tank size is expressed in gallons, commonly ranging from 250 to 1,000. Smaller containers are called cylinders. The number of gallons needed by a household relates to the total number of British thermal units, a measure of energy output, used by all of the appliances in the building. Other considerations in tank size are the number of heating days per year, square footage of the house and contemplated future additions, such as a pool or hot tub. Local building codes contain requirements for placement and regulations for above and underground placement of specific sizes.
Weights and measurements of tanks vary by manufacturer, but manufacturers adhere to ASME standards for the industry that are determined by the American Society of Mechanical Engineers. Major manufacturer 250-gallon tanks weigh between 472 and 500 pounds and measure from 86 to 94 inches long. A 500-gallon tank weighs from 871 to 949 pounds and averages 119 inches in length. The largest residential tank, a 1,000-pound tank, weighs from 1,729 to 1,800 pounds and averages nearly 192 inches in length. Measured from the bottom to the top of the service fitting, propane tanks average between 38 and 50 inches. Diameters range between 30 and 41 inches.
A Connecticut supplier suggests a 500-gallon tank as a minimum size for an average four-bedroom home. Although this figure is computed to power a whole house, the furnace is the major consumer of fuel. The midsized tank might be more than adequate for a house where only the furnace depends on propane, and a once-a-year fill would allow the homeowner to time fills for advantageous rates. In colder climates or where high energy-use alliances such as a pool or hot tub might add to the load, a 1,000-pound tank or an additional smaller tank might make a prudent investment.