Water Heating

Farm operations and related facilities need to be comfortable and clean, and this requires large amounts of hot water. Propane water heaters can meet the hot water needs of agricultural operations efficiently and economically.

Propane water heaters have many advantages over electric units:

• Lower cost: On average, the first cost of propane water heaters is 42 percent less than comparable electric heaters. In general, they also cost less to operate. Over an average unit's life span, a propane gas water heater can save farmers nearly $2,000 compared with an electric model.
• Better recovery rates (recovery rate is the number of gallons per hour that a water heater can produce): Propane gas water heaters heat more than twice as much water in an hour than comparable electric models. A smaller propane-fueled unit with a high recovery rate can outperform a larger electric model. For example, a small 30-gallon propane model can recover up to 55 gallons per hour, while a 52-gallon electric water heater is needed to produce the same amount of hot water.

Higher total energy efficiencies: All water heaters have efficiency ratings indicating how many Btu's are actually used to heat the water. However, the system efficiency of electricity (taking into account the energy used to produce the electricity in the first place) is only about 28.5 percent, compared with 93 percent for propane. A propane heater with 75 percent combustion efficiency is actually more efficient than an electric model rated at 100 percent efficiency. Higher efficiency means lower operating costs for farmers.

Propane and Electric Water Heaters Efficiency Comparisons

Unit	Rated Efficiency (A)	System Efficiency (B)	Total Energy Efficiency (A) X (B)
Electric	100% (equipment efficiency)	28.5%	28.5%
Propane	75% (combustion efficiency)	93.0%	69.8%

Many different models of propane gas water heaters are available for farm use, but there are just two basic designs:

• Storage: The predominant design of gas water heaters is the storage water heater with a bottom-burner configuration. Heated water is held in thermostatically controlled storage tanks. Propane storage heaters can produce up to four times as much hot water as electric models in the same amount of time. These heaters are generally sold as two separate components: the water heater and the storage tank. The water heaters can range from small (100,000 Btu/hr) to very large (2 million Btu/hr), and the tanks may have capacities ranging from 80 to 4000 gallons.
• Instantaneous: Tankless or instantaneous water heaters do not heat water continuously. A gas burner automatically ignites when the faucet is turned on and water is heated instantly. When the faucet is turned off, the unit shuts off. Initial costs are higher than for storage models, but over time they can be more economical. Smaller instantaneous heaters are widely used on farms.