Yes, a water heater can use either LP (liquid propane) or natural gas, depending on its design and the type of gas supply available in your area.
Gas water heaters are popular for their efficiency and cost-effectiveness. But homeowners often wonder whether they can use both LP (propane) and natural gas. The answer depends on the water heater model and its configuration.
Natural Gas vs. Propane Water Heaters
Most gas water heaters are designed to run on either natural gas or propane, but not both interchangeably. The key differences lie in their fuel delivery systems and combustion requirements.
Fuel Compatibility
Standard water heaters come preset for one fuel type:
- Natural gas models require 1,030 BTUs per cubic foot
- Propane models need 2,516 BTUs per cubic foot
This significant difference means the burner orifices and gas valves must be specifically sized for each fuel type. Using the wrong fuel can lead to dangerous conditions or poor performance.
Convertible Models
Some manufacturers offer convertible water heaters that can switch between fuels with a conversion kit. These units typically include:
- Dual-rated gas valves
- Interchangeable burner orifices
- Adjustable air shutters
For example, the 30 Gallon Tall Direct Vent Water Heater comes preset for natural gas but includes a propane conversion kit.
Cost Comparison
When choosing between fuels, consider both upfront and operating costs:
| Factor | Natural Gas | Propane |
|---|---|---|
| Cost per BTU | $2.59/GGE | $3.53/GGE |
| Installation | $2,000+ for new gas line | $300-$1,000 for tank |
| Efficiency | Lower BTU output | Higher BTU output |
While propane burns hotter, natural gas typically costs less overall. According to ENERGY STAR, propane water heaters may qualify for additional tax credits that can offset the higher fuel costs.
Installation Considerations
Natural Gas Requirements
- Requires connection to municipal gas lines
- Needs proper pressure regulation (typically 7″ water column)
- Ventilation must meet local codes
Propane Requirements
- Needs on-site storage tank (100-1,000 gallon capacity)
- Requires periodic fuel delivery
- Must have proper pressure regulation (11″ water column)
For homes without existing gas service, propane often proves more practical. As noted in our guide to home heating systems, propane tanks can be installed above or below ground.
Safety and Maintenance
Both fuel types require proper handling:
- Natural gas is lighter than air and dissipates quickly if leaked
- Propane is heavier than air and can pool in low areas
- Both need carbon monoxide detectors nearby
- Annual professional inspections recommended
According to the U.S. Department of Energy, properly maintained gas water heaters can last 10-15 years, regardless of fuel type.
Environmental Impact
Propane offers some ecological advantages:
- 95% of U.S. propane is domestically produced
- Burns cleaner than natural gas
- Doesn’t contaminate groundwater
However, natural gas infrastructure already exists in most urban areas, reducing the need for additional storage tanks.
Making the Right Choice
Consider these factors when selecting your water heater fuel:
- Existing home infrastructure
- Local fuel availability and pricing
- Upfront installation costs
- Long-term operating expenses
- Environmental preferences
For most homes connected to natural gas lines, sticking with natural gas makes financial sense. Rural properties often benefit from propane’s flexibility. Always consult with a licensed professional before making changes to your water heating system.
