Propane gets the job done. It heats homes, powers stoves, fires up water heaters, and keeps grills running throughout the year. But homeowners who switch from propane to natural gas almost never go back, and the reason is straightforward: natural gas arrives through a utility line without requiring a tank, a delivery schedule, or the sinking feeling of running out of fuel on a cold night. The long-term cost is lower, the supply is continuous, and the gas line conversion that makes it possible is a one-time project with benefits that compound over years of lower utility bills.
The part that gives homeowners pause is the conversion itself. Propane and natural gas are not interchangeable. They operate at different pressures, require different orifice sizes in appliance burners, and need different regulators to function correctly. An appliance set up for propane that is connected to a natural gas line without a proper gas line conversion will either produce an incorrect flame, fail to ignite, or in a worst case, create a hazardous condition from unburned gas. The conversion is not optional or cosmetic. It is a technical requirement, and it is one that must be performed by a licensed plumber or gas technician who can do it correctly and inspect the result before the appliance goes back into service.
A gas line conversion from propane to natural gas requires replacing or adjusting the burner orifices in every affected appliance, swapping the pressure regulator to match natural gas supply pressure, connecting the appliance to the natural gas supply line, and having a licensed professional inspect and test the entire system before use. The conversion is appliance-specific and cannot be completed safely without the correct conversion kit for each individual unit.
Propane vs. Natural Gas: What Actually Differs
Propane and natural gas are both fossil fuels that combust cleanly and efficiently, but their physical properties require different delivery systems and appliance configurations. Natural gas is lighter than air and is delivered at lower pressure through utility mains. Propane is denser than air, stores as a liquid under pressure in tanks, and is vaporized and delivered at higher pressure to appliances. The pressure difference between the two fuels is the core reason a gas line conversion requires hardware changes rather than just a supply line swap.
The burner orifice in a gas appliance is a precisely sized opening that meters the fuel entering the combustion chamber. A propane orifice is smaller than a natural gas orifice for the same appliance because propane has higher BTU content per cubic foot and is delivered at higher pressure. Connecting a propane-configured appliance to natural gas without changing the orifice produces a weak, inefficient flame because the natural gas supply pressure is insufficient to deliver the fuel volume the oversized orifice requires. The regulator mismatch compounds this: a propane regulator set for the higher propane supply pressure will either overpressure a natural gas line or fail to regulate correctly at natural gas supply pressure. Both conditions are addressed by the conversion process.
Propane vs. Natural Gas: Key Differences
| Factor | Propane | Natural Gas | Advantage |
| Energy content per cubic foot | 2,516 BTU | 1,030 BTU | Propane (denser fuel) |
| Cost per BTU (Michigan avg.) | Higher ongoing cost | Lower ongoing cost | Natural gas |
| Supply method | Delivered by truck; requires tank | Piped continuously from utility | Natural gas (no runout risk) |
| Appliance orifice size | Smaller (higher pressure) | Larger (lower pressure) | N/A — must match fuel type |
| Pressure regulator | Higher pressure regulator | Lower pressure regulator | N/A — must match fuel type |
| Gas line conversion required | No (existing system) | Yes — orifices and regulators | Natural gas (after conversion) |
| Environmental impact | Higher carbon per BTU | Lower carbon per BTU | Natural gas |
| Availability in Michigan | Rural areas; tank delivery | Urban and suburban areas | Depends on location |
The BTU content difference in that table is what drives the orifice size requirement in a gas line conversion. Propane delivers roughly 2.5 times the energy per cubic foot that natural gas does, so a propane orifice calibrated for that energy density is too small when natural gas is the fuel. Installing the correct natural gas orifice delivers the right fuel volume at natural gas supply pressure, producing the proper flame height, heat output, and combustion efficiency the appliance was designed to achieve.
Why a Gas Line Conversion Must Be Done by a Licensed Professional
The conversion itself is a series of precision mechanical tasks: removing and replacing orifices that are threaded into burner assemblies, swapping regulators, adjusting air-to-fuel mixture settings, and connecting to the natural gas supply line with fittings that meet local code. None of these steps is conceptually difficult. All of them require the correct parts, the correct tools, knowledge of the specific appliance’s conversion specifications, and the ability to test the result for gas leaks and correct combustion before the appliance is put back into service.
Michigan requires that gas line work, including gas line conversion from one fuel type to another, be performed by a licensed plumber or gas utility technician.
Beyond the legal requirement, the practical safety argument for professional gas line conversion is compelling: an incorrectly converted appliance can produce carbon monoxide from incomplete combustion, create a leak at an improperly seated orifice or regulator connection, or operate outside its designed parameters in ways that damage the unit or create a fire risk. A licensed plumber performs the conversion correctly, tests every connection with a leak detector, and verifies combustion before the appliance is returned to service.
What a Gas Line Conversion Involves for Each Appliance Type
The gas line conversion process is specific to each appliance type, and homes switching from propane to natural gas typically have multiple appliances that all need conversion at the same time. A furnace, a water heater, a gas range, a gas dryer, and an outdoor grill all have different conversion kits, different orifice configurations, and different regulator requirements. A plumber performing a whole-home conversion works through each appliance systematically, using the manufacturer’s conversion kit for that specific model rather than generic parts.
Furnaces and Boilers
A gas furnace or boiler conversion involves replacing the main burner orifice, the pilot orifice if the unit has a standing pilot, and the gas valve regulator. Many modern furnace gas valves have a built-in regulator that is adjusted rather than replaced, using a conversion adjustment described in the manufacturer’s documentation. After the conversion hardware is installed, the manifold pressure is tested with a manometer to confirm it matches the natural gas specification for that unit before the furnace is fired.
Water Heaters
Tank water heater conversion follows a similar process to a furnace conversion: the main burner orifice and pilot orifice are replaced, and the gas valve is converted or replaced according to the manufacturer’s specifications. Tankless water heater gas line conversion is more involved because the combustion system is more sophisticated, and not all tankless units are convertible between fuel types. Confirming that the specific tankless model has an available conversion kit before planning a gas line conversion is an important first step for homes with tankless units.
Gas Ranges and Ovens
A gas range conversion replaces the orifice at each burner, including the oven burner and the broiler burner, with natural gas orifices from the manufacturer’s conversion kit. The range pressure regulator is also replaced or adjusted. After conversion, each burner is tested for ignition, flame height, and flame color. A properly converted natural gas burner produces a steady blue flame with a small inner cone. A yellow or orange flame after gas line conversion indicates incomplete combustion and requires adjustment of the air shutter or a recheck of the orifice installation.
Gas Dryers
Gas dryer conversion is one of the simpler appliance conversions because most residential gas dryers have a single burner with a single orifice and a straightforward regulator configuration. The conversion kit for most major dryer brands includes the replacement orifice and any required regulator adjustment instructions. After conversion, the dryer is test-fired and the flame is observed through the access panel to confirm correct ignition and flame characteristics before the appliance is returned to normal operation.
Outdoor Gas Grills and Appliances
Outdoor gas grills require a gas line conversion that includes replacing the orifice at each burner, adjusting the regulator, and in many cases replacing the hose and regulator assembly entirely if the grill was previously connected to a portable propane tank rather than a permanent line. Grills that are being connected to a permanent natural gas line as part of the gas line conversion also need an outdoor shutoff valve installed at the connection point as a code requirement in most Michigan jurisdictions.
The Natural Gas Line Connection
The gas line conversion of the appliances themselves is only part of the project when a home is switching from propane to natural gas for the first time. A natural gas service line must be connected to the home from the utility main, and the interior gas piping must be sized and routed to serve all of the appliances being converted. This portion of the project involves coordination with the natural gas utility for service connection and meter installation, and licensed plumbing work for all interior gas piping.
Interior gas line sizing for a gas line conversion from propane to natural gas may require upsizing the existing gas piping. Because natural gas has lower energy density per cubic foot than propane, the volumetric flow rate required to deliver the same BTU output to the appliances is higher. Pipes that were correctly sized for propane may be undersized for natural gas delivery to the same appliances at the same rate. A licensed plumber performing the conversion assesses the existing piping and determines whether upsizing any runs is necessary to deliver adequate flow to each appliance.
How Long a Gas Line Conversion Takes
A whole-home gas line conversion involving a furnace, water heater, range, and dryer typically takes a full day for an experienced licensed plumber, not counting the utility connection and meter installation that the natural gas company handles on their own schedule. Homes that also need new interior gas piping runs or piping upsizing add time proportionally. The sequence is usually: coordinate the utility connection date, complete all interior piping work and appliance conversions, and then schedule the final inspection after the utility service is active and the system can be fully tested under live gas pressure.
Michigan requires a permit for gas line work, and it should be inspected by the local building department before the system is put into continuous service. A licensed plumber handles the permit application as part of the project, and the inspection confirms that all connections are correctly made, all appliances are properly converted, and the system meets current Michigan Mechanical Code requirements. Skipping the permit creates liability for the homeowner and can complicate insurance claims if a future incident involves the gas system.
Is a Gas Line Conversion Worth It for Your Michigan Home?
The financial case for a gas line conversion in Michigan depends on current propane and natural gas prices, the volume of fuel the home uses annually, and the one-time cost of the conversion project. Natural gas has historically been less expensive per BTU than propane in Michigan, and the margin is significant enough that most homeowners in areas with natural gas availability recover the conversion cost within a few years through lower fuel bills. The elimination of delivery scheduling, the removal of the propane tank, and the continuous supply reliability are additional benefits that do not have a precise dollar value but consistently matter to homeowners who have dealt with propane delivery logistics for years.
For homes in rural Michigan areas where natural gas service is not available, the gas line conversion option depends entirely on whether the utility has extended its mains to the area or plans to do so. A licensed plumber or the local utility can confirm whether natural gas service is available at a specific address and what the service connection cost would be as part of the overall gas line conversion project estimate.
Schedule Your Gas Line Conversion With Aspen Plumbing Services
Aspen Plumbing Services handles gas line conversion projects for Michigan homeowners, including appliance orifice and regulator conversion, interior gas piping work, permit coordination, and system testing. If you are ready to make the switch from propane to natural gas or want to understand the full scope and cost of a conversion for your home, we can walk you through every step.
Contact Aspen Plumbing Services today to schedule your gas line conversion consultation.
Frequently Asked Questions
Can I convert a propane appliance to natural gas myself?
No. A gas line conversion requires a licensed plumber or gas technician in Michigan, and attempting it without a license violates state code. Beyond the legal requirement, the technical risks of an incorrectly performed conversion include gas leaks at improperly seated orifices, carbon monoxide production from misconfigured combustion, and appliance damage from incorrect fuel pressure. The conversion kit and orifice hardware are available at plumbing supply stores, but the installation, testing, and inspection must be performed by a licensed professional.
Do all propane appliances have a natural gas conversion kit available?
Most major residential appliances have manufacturer-supplied gas line conversion kits available, but not all. Some older appliances and certain specialty units are designed for a single fuel type and do not have a conversion option. Confirming that a conversion kit is available for each specific appliance model before planning the conversion project prevents the situation of discovering mid-project that a particular unit needs replacement rather than conversion. A licensed plumber can help identify which appliances are convertible and which need to be replaced as part of the transition.
How much does a gas line conversion cost in Michigan?
The cost of a gas line conversion varies based on the number of appliances being converted, whether new interior gas piping is needed, and the cost of the natural gas utility connection. A conversion involving four to five standard residential appliances with no new piping runs typically ranges from $500 to $1,500 for the appliance conversion work alone. Adding new interior gas piping, upsizing existing runs, or connecting outdoor appliances adds cost proportionally. A licensed plumber can provide an accurate estimate after assessing the specific appliances and the existing gas piping configuration.
What happens if a propane appliance is connected to natural gas without conversion?
An unconverted propane appliance connected to natural gas will operate incorrectly because the propane orifice is too small and the pressure regulator is set for higher propane supply pressure. The result is typically a weak, yellow flame from insufficient fuel delivery, potential for incomplete combustion producing carbon monoxide, and in some cases no ignition at all. Running an appliance in this configuration damages the unit over time and creates a genuine safety hazard. The gas line conversion is not optional when switching fuel types.
How long does it take to get natural gas service connected in Michigan?
The timeline for natural gas utility connection varies by utility and by the extent of work required to bring service to the property. For homes where the utility main runs along the street in front of the property, connection can sometimes be completed within a few weeks of application. For properties that require the utility to extend its mains a significant distance, the project may take months and may involve a service extension fee. Contacting the local natural gas utility early in the planning process gives the most accurate timeline for the specific address.
Does a gas line conversion require a permit in Michigan?
Yes. Gas line work in Michigan requires a permit, and a conversion that involves appliance modifications and gas piping work is subject to inspection by the local building department. The permit ensures that the work is inspected by an authority who confirms it meets current Michigan Mechanical Code standards before the system is put into continuous service. A licensed plumber handles the permit application as part of the gas line conversion project. Unpermitted gas work creates liability for the homeowner and may affect coverage for insurance claims involving the gas system.
Aspen Plumbing Services proudly serves the greater Jackson, Michigan area and the surrounding areas, including Albion, Marshall, & Eaton Rapids. Questions about gas line conversion or any of our plumbing services? Contact our team today
