Whether or not propane water heaters are efficient is highly dependent upon how one defines efficiency. Efficiency can refer to convenience, ease of use, or the certainty that hot water will be available at all times. It can also refer to energy costs and environmental friendliness. Water heaters that run on propane are generally quite efficient under all these criteria, at least as compared to electric water heaters.
Approximately one-fifth of the average US household’s yearly energy costs are caused by its hot water heater. The price of showers, baths, hot tubs, and dishwashers do not come cheap. They do however, become somewhat less expensive with propane.
Water heaters basically come in two forms. Most heaters are of the storage tank variety. They hold 50 gallons (about 189 liters) or more of water, and keep it heated at all times. The second type of heater, which is usually more expensive at the onset but very cost-effective in the long term, is the tankless water heater. These devices may have a somewhat lower flow, but they heat and provide water only as needed.
Propane water heaters of the storage tank design will fill up and heat water in about half the time of an electric model. Moreover, they will do so at approximately one-third less cost. Savings increase even more with tankless water heaters that use propane. Power bills are sometimes as much as 60% lower than electric models.
Environmentally speaking, propane is also the more efficient choice. As less electricity is needed or used by the individual consumer, power plants that produce electricity are able to lower their capacity. In the case of coal-fired power plants, this translates to fewer carbon dioxide emissions released into the atmosphere.
With any type of hot water heater, efficiency can be enhanced with a few simple steps on the part of the consumer. Often, efficiency is based not so much on the heater itself, but on how a homeowner cares for and uses it. Heating the water for a 20-minute shower requires less power than heating water for a 30-minute shower. Also, insulation of both the water heater itself, and hot water pipes, will do much do reduce stand-by heat loss.
Another simple step is to lower the temperature on the water heater. As a rule, hot water heaters are set to 140°F (60°C). Reducing that temperature to 120°F (about 49°C) can produce a surprising amount of savings.