Like natural gas water heating systems, propane water heaters are very efficient and reliable units and a great alternative when natural gas is not a viable option. They differ in properties that affect combustion and safety.
Propane gas, LP, or liquid petroleum is common in urban and suburban residential areas. LP is also known as rural fuel because it is not delivered to homes by gas pipelines like natural gas but by the truck that delivers and fills up the residential storage tanks, often adjacent to the house.
Since propane gas has a relatively high density, you must be very careful in handling the propane. Unlike natural gas that dissipates, propane gas tends to collect and settle at the lowest point of the room where LP water heaters are installed. Gas detectors are recommended.
When buying one of the propane water heaters brands, you will notice that they are the same as natural gas water heaters and that the conversion kit is usually included, which modifies the gas orifice and gas pressure regulator on the unit.
The gas burner is often the same, but propane hot water heaters need more air for LP combustion, so that is what one must be aware of.
Note: Operating gas pressure for propane water heaters is much higher than for natural gas due to the higher BTU and specific gravity.
When searching for propane water heaters, you can choose between the storage or tank type and on-demand or tankless models like natural gas units.
Note: All heaters are rated for combustion efficiency, or how many BTUs are used to heat water. If a standard heater has a combustion efficiency of 80 percent, 80 percent of the available BTUs are being used for heating. The other 20 percent is lost up the flue.
Propane hot water tanks are designed with capacities ranging from 40 gallons to more than 100 gallons. Tank-type propane water heaters work on the same principle as tanks on natural gas, and you can find more info here.
Note: The 50-gallon LP water heater can provide as much hot water as 66-88-gallon electric unit in 2.5 baths home.
When installing these conventional tank-type propane water heaters, you will see in the manual that they are subject to special requirements for venting.
Usually, there are two manuals, one is for installation, and the other describes venting requirements. This is one of the reasons why we recommend a licensed plumber/ professional. More about propane here.
Propane tankless water heaters are also popular as they offer modern and space-saving designs; they are much more efficient than tank-type, using less fuel and decreasing emission and greenhouse gases. The process of how they prepare hot water is similar to natural gas combustion. For more info about tankless heaters, read here.
Tip: LP water heaters should not be installed in a basement if such installation is prohibited by federal, state, local laws and codes.
If we compare prices between the tank-type and tankless water heaters using LP as a fuel, these instant units are costing up to twice that of standard models. However, the saving comes from the operating costs, and on-demand models can pay for themselves in a short time.