When it comes to buying a gas-powered water heater, you can either choose to settle for a unit that uses propane or natural gas. There’s very little difference though in how well propane and natural gas perform when powering appliances for heating water. If you want to know which of the two energy sources is superior, it’s important to compare their efficiency, cost and risk factors.

One way to measure energy efficiency of gas water heaters is by comparing thermal output of various fuels used. Heat is measured in Thermal British Units. This tells you the amount of thermal energy that is needed to raise the temperature of 0.5kg (1lb) of water to 1 degree F (0.56 degrees C).

One cubic foot of natural gas provides about 1,000 BTUs. The same amount of propane provides 2,500 BTUs. This means that propane contains about 1.5 times more usable energy content. When used for heating, most people can’t tell the difference between propane and natural gas. (But you’ll use less propane to produce the same amount of energy as natural gas.)

While propane may be more efficient as an energy source, it tends to cost more than natural gas. Both of these gases can ignite and cause an explosion if they collect to significant amounts when there is a leakage. Since propane is heavier than natural gas, this means that it falls to the ground and dissipates into the air at a slower rate, which increases its explosive risk.

If you live in areas outside of natural gas service lines, propane water heaters will be your primary choice. The following guide will focus on water heaters that use this type of fuel. Keep reading to learn more about the different propane water heaters that are available and what to expect from your purchase.

Types of Propane Water Heaters

Selecting the best propane water heater ultimately boils down to your household needs and budget. As far as options go, you can either go for a tankless or standard water heater. The latter option utilizes a tank to hold hot water prior to use.

In these types of hot water systems, a propane burner is located at the bottom of the tank. The burner heats water to a preset temperature determined by a thermostat setting. Water is heated constantly to maintain the set temperature regardless of use, and for this reason, standard propane water heaters have a high-energy use. However, these types of heaters are attractive to those on a restrictive budget because they tend to cost less than the more energy efficient tankless propane heaters.

Tankless propane water heaters cost more to install but the long term savings they provide make them a worthwhile investment. By sensing an open valve and igniting propane automatically to heat coils through which water flows, these units provide hot water on demand. Because tankless propane heaters operate only when a hot water fixture is opened, they save more energy. What’s more, these units save on space because there’s no need to accommodate a storage tank. Depending on the model and size, you can even mount them on a wall or under a sink.